Search

Abstract Xiaozhou mustard (Brassica napiformis) root tuber, a traditional fermented vegetable, has a long history in Rongan County, Guangxi Province. However, the frequent occurrence of root tuber sour rot by Geotrichum candidum (G. candidum) has seriously reduced Xiaozhou mustard production and quality in recent years. The objective of the present study is to investigate the antifungal efficacy of 2-chloro-5-trifluoromethoxybenzeneboronic acid (Cl-F-BBA) against G. candidum and its possible mechanisms. The results revealed that a concentration of 0.25 mg/mL Cl-F-BBA completely halted mycelial growth and spore germination. Furthermore, a slightly lower concentration of 0.20 mg/mL was sufficient to compromise the integrity of the plasma membrane in mycelia and mitochondria, leading to a reduction in respiratory rate, activities of malate dehydrogenase (MDH), and succinate dehydrogenase (SDH), ATP content, and energy charge. This concentration also significantly disordered antioxidant metabolism, resulting in the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA), and caused intracellular leakage in mycelia. In vivo experiments further demonstrated that Xiaozhou mustard root tubers treated with Cl-F-BBA exhibited markedly lower decay rates and lesion diameters compared to the control group. In summary, Cl-F-BBA presents a promising solution for controlling root tuber sour rot in Xiaozhou mustard caused by G. candidum.

The valorization of industrial waste in the production of new products is a growing trend, with food waste showing significant promise as a raw material for various industries. Thus, this research aimed to investigate the production of Geotrichum candidum lipase using industrial waste, such as mozzarella cheese whey (MCW) and corn steep liquor (CSL), and to analyze how effectively it catalyzes the esterification of oleic acid with methanol. Lipase production was carried out in medium containing MCW and CSL, with fermentation conditions optimized using a fractional factorial experimental design and central composite experimental design. The highest activities (16.71 U/mL in 24 h and 17.80 U/mL in 48 h) were found in conditions of 13.6% (%w/v) CSL and 37.1% (%w/v) MCW, with corn oil fixed at 1% (%w/v) and pH fixed at 6,00. Esterification conditions were evaluated at atmospheric pressure, both in a solvent-free environment and using hexane, as well as under high pressures with supercritical carbon dioxide (SC-CO2). The produced lipase demonstrated high catalytic activity for the esterification reaction of oleic acid with methanol under SC-CO2 with an increase of 39.41% in the yield. The yields found confirm the feasibility of producing lipase from industrial waste, thus presenting it as a sustainable and efficient alternative for industrial processes, and show that there is no need to use toxic organic solvents in esterification reactions. [ABSTRACT FROM AUTHOR]

Mustard essential oil (MEO) nanoemulsions fortified with citrus pectin and tween-80 (MEO-NE-PT) or tween-80 (MEO-NE-T) were prepared by high-pressure homogenization followed by ultrasonication, and comparative analysis was performed on the microstructure, storage stability, pH, ionic strength and thermal tolerance between MEO-NE-PT and MEO-NE-T. The application of MEO-NE-PT to the postharvest preservation of ‘Shatangju’ mandarin was evaluated. It was found that MEO-NE-PT exhibited superior stability with smaller fluctuations in particle size and polydispersity index (PDI). The minimum inhibitory concentration (MIC) of MEO-NE-PT was 64 μL/L, much lower than those of MEO (256 μL/L) and MEO-NE-T (128 μL/L). Furthermore, after MEO-NE-PT treatment at 64 μL/L for 6 h, the germination rate of Geotrichum candidum spores was only 6.67%, and the length of the germ tube was only 8.57 μm, both significantly lower than 100% and 165.02 μm for the control group (MEO), respectively. The results of scanning electron microscopy (SEM) revealed that treatment with MEO-NE-PT caused the mycelium of Geotrichum candidum to wrinkle and break apart. Compared with the control group, MEO-NE-PT treatment could significantly reduce the decay rate and quality loss of ‘Shatangju’ mandarin, while delaying the decline in hardness and total soluble solids. As a safe and effective antimicrobial agent, MEO-NE-PT could control the growth of Geotrichum candidum and maintain the post-harvest quality of ‘Shatangju’ mandarin.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, the chemical compositions of rosemary (Rosmarinus officinalis Spenn.) and sweet marjoram (Origanum majorana L.) essential oils, both individually and in various blend ratios, were investigated by using Gas Chromatography-Mass Spectrometry. Their antifungal activities were also determined against the potato rubbery rot disease agent, Geotrichum candidum, under in vitro and in vivo conditions. Camphor (20.69%) and terpinen-4-ol (35.13%) were determined as primary constituents in rosemary and sweet marjoram essential oils, respectively. Sweet marjoram and rosemary essential oils completely inhibited mycelial growth of G. candidum at 55.0 and 65.0 µL/Petri concentrations, respectively. Essential oils at these concentrations were found as fungicidal. Notably, a synergistic fungicidal antifungal effects were also observed in essential oil blends. Blend of sweet marjoram and rosemary essential oil in a 3:1 ratio (O75R25) significantly enhanced antifungal activity at the relatively lower concentration (45.0 µL/Petri). Microscopic observations revealed structural deformations in exposed hyphae, including cytoplasmic coagulation and vacuolization. Essential oil blend (O75R25), sweet marjoram and rosemary essential oils completely inhibited the disease lesion caused by G. candidum on potato tubers at concentrations of 100.0, 125.0, and 150.0 µL/L air, respectively. These findings emphasized that essential oil blends of rosemary and sweet marjoram have synergistic antifungal potential and can be used as effective biofungicides against plant fungal diseases. [ABSTRACT FROM AUTHOR]

Fungi inflict a great deal of damage to crops in fields and in storage facilities, causing issues such as leaf spot, wilt, rust, dieback and rot, as well as releasing mycotoxins that taint vegetation. In the current study, 25 de novo fungal isolates were taken from infected plant tissue (leaf, root and fruit), at pre- and post-harvest stages. Isolates were identified using molecular markers; 8 genera and 15 species were determined. The most common species was Penicillium spp. (40%), Aspergillus spp. (20%), Fusarium spp. (16%) and Alternaria alternata species (8%). The remaining 16% was comprised of various types of fungi, including Geotrichum candidum, Neofusicoccum parvum, Rhizopus stolonifera and Mucor fragilis. Many of these genera are known to cause significant crop damage and are notorious mycotoxin producers. An evaluation of the optimal growth temperature revealed the ideal temperatures were 30 °C for 56% of isolates, 25 °C for 28% of isolates and 20 °C for 16% of isolates. An assessment of water activity showed that 60% of isolates belonged to Penicillium and Aspergillus spp. and were mesophilic and xerophilic. Another 28% of isolates were Fusarium spp., Geotrichum candidum, Neofusicoccum parvum and Mucor fragilis, and hydrophilic. The remaining 12%, representing Alternaria alternata and Rhizopus stolonifera, were mesophilic. The current study provides accurate eco-physiological response data and molecular information for each isolate. The findings can assist the development of novel approaches to control the expansion of invasive fungal infections and minimise their deleterious consequences. [ABSTRACT FROM AUTHOR]

When firm implantation has occurred, pregnancy losses during the late embryonic or early fetal period are less common and typically occur before 60 days of gestation. A rare case of early fetal death due to Geotrichum candidum infection in a pluriparous Jersey crossbred cow was sporadically recorded during routine screening at the university cattle farm. The early fetal death was diagnosed using sequential sonographic examinations, and the aetiology was confirmed through microbiological examination and histopathological evaluation of an endometrial biopsy sample. It is concluded that, although mycotic abortions and fetal deaths are uncommon and sporadic, routine screening of cows for late embryonic and early fetal death remains essential. [ABSTRACT FROM AUTHOR]

Palm kernel cake (PKC), a byproduct of palm oil extraction, serves an important role in Ecuador's animal feed industry. The emergence of yellow-orange fungal growth in PKC on some cattle farms in Ecuador sparked concerns within the cattle industry regarding a potential mycotoxin-producing fungus on this substrate. Due to the limited availability of analytical chemistry techniques in Ecuador for mycotoxin detection, we chose to isolate and identify the fungus to determine its association with mycotoxin-producing genera. Through molecular identification via ITS region sequencing, we identified the yellow-orange fungus as the yeast Candida ethanolica. Furthermore, we isolated two other fungi—the yeast Pichia kudriavzevii, and the fungus Geotrichum candidum. Molecular identification confirmed that all three species are not classified as mycotoxin-producing fungi but in contrast, the literature indicates that all three have demonstrated antifungal activity against Aspergillus and Penicillium species, genera associated with mycotoxin production. This suggests their potential use in biocontrol to counter the colonization of harmful fungi. We discuss preventive measures against the fungal invasion of PKC and emphasize the importance of promptly identifying fungi on this substrate. Rapid recognition of mycotoxin-producing and pathogenic genera holds the promise of mitigating cattle intoxication and the dissemination of mycotoxins throughout the food chain. [ABSTRACT FROM AUTHOR]

Abstract Background Postharvest diseases cause a wide loss to tomato fruits during handling and storing from harvest to consumers. Fungicides are mainly used to control postharvest diseases. Biological control is the eco-friendly substitute strategy used for postharvest diseases management as which becoming promise worldwide. Six bacterial bioagent (i.e., Bacillus subtilis, B. amyloliquefaciens, Pseudomonas resinovorans, P. alcaligenes, P. putida and P. stutzeri) were tested to suppress both Geotrichum candidum and Alternaria alternata causal agents of tomato fruit rots during storage. Results In vitro, most of bioagents significantly reduced mycelial growth rate of G. candidum. Both of B. subtilis and P. stutzeri were the most superior bacterial bioagents with values 67.03 and 72.2%, respectively. In addition, B. subtilis and B. amyloliquefaciens resulted in the most superior over all antagonists against A. alternata. The lowest percent of disease incidence and severity of G. candidum were obtained by B. subtilis and P. stutzeri. The maximum reduction percent of it on tomato fruits was recorded by applying B. subtilis and P. stutzeri with values (90 and 87%) and (91, 89%) in both seasons, respectively. Also, the highest reduction of A. alternata was obtained by using B. subtilis, which resulted in 85 and 84% in both seasons, respectively. The application of bioagents against both pathogens was significantly improved fruit quality aspects (weight loss, vitamin C, TSS and acidity %) during storage period compared to infected control fruits. Conclusion The findings revealed that both of B. subtilis and P. stutzeri could be potential biological control agents against most postharvest pathogens of tomato fruits. This might be an alternative control strategy instead of fungicides which service the sustainable and organic farming.

Abstract Background Oral geotrichosis is an infection caused by Geotrichum species. It is an uncommon opportunistic oral fungal infection caused mainly by Geotrichum candidum and rarely found in immunocompetent hosts. This report attempted to highlight a case of unusual geotrichosis, which requires accurate observation, as well as indicate the appropriate diagnostic methods that may contribute to eliminating the misdiagnosis of this fungal infection. Case presentation We report of unusual isolation of Geotrichum silvicola and Geotrichum candidum from the oral cavity of a 15-year-old immunocompetent female with a sign of oral geotrichosis. The isolation of Geotrichum silvicola and Geotrichum candidum was performed using Mitis Salivarius Agar. After a month of prescribing appropriate medication and improving oral hygiene, the patient showed the absence of all the signs of geotrichosis without any complaints and an improvement in overall oral health. Conclusions The isolation of Geotrichum silvicola and Geotrichum candidum from the oral cavity of an immunocompetent patient is considered an unusual and rare case that documented for the first time.

Pectinases are applied in many commercial processes, particularly for fruit juice clarification. Cost effective production of pectinase necessitates utilization of agro-industrial wastes as fermentation raw materials. Biomass from halophytic plants provides a prospect for its sustainable utilization in industrial processes. Here, we report utilization of two halophytic biomasses, Suaeda fruticosa and Cressa cretica to grow a pectinolytic strain, Geotrichum candidum AA15 and its mutant strain AHC1. Amount of pectinase produced was compared by cultivating the strains in the medium containing apple peels and orange peels. The data showed that G. candidum AHC1 can produce pectinase titers of 15.43 and 28.15 IU mL−1 within 25 h when cultivated in the medium containing biomass from C. cretica and S. fruticosa, respectively. The results of FTIR and Scanning Electron microscopy affirmed the bacterial growth mediated changes in the structure of the substrate that was associated with the pectinase production. The crude pectinase preparation was applied to hydrolyze an agro-waste, sugarcane bagasse, that resulted in the release of 86 mg g−1 of reducing sugars. Thus, this study proposed the usage of halophytic plant biomass for cost effective pectinase production and its application for saccharification of agro-waste. [ABSTRACT FROM AUTHOR]

Geotrichum candidum is a dimorphic yeast used in cheese processing. To our knowledge, no major metabolites have been identified to date in G. candidum except for some amino acid and fatty acid metabolites. This has limited research on the commercial use of G. candidum. In this study, we aimed to analyze temporal changes in the intra- and extra-cellular metabolites of G. candidum and Saccharomyces cerevisiae cultured in YM medium as reference. As a result of metabolite analysis, it was observed that G. candidum tends to accumulate pentose phosphate pathway compounds, which are involved in nucleic acid synthesis, after 48 h of cultivation when compared to S. cerevisiae. In addition, G. candidum accumulated higher amounts of the antioxidant glutathione in the medium than did S. cerevisiae. In addition, G. candidum accumulated large amounts of B vitamins such as pantothenic acid and nicotinic acid in the medium. Finally, we examined the potential of G. candidum as a host for the production of useful compounds such as pantothenic acid. When cultured in medium supplemented with the pantothenic acid precursor β-alanine, G. candidum produced 12-fold higher amounts of pantothenic acid (30 μM) than that by S. cerevisiae. This study indicates that G. candidum accumulates various useful compounds that are dissimilar to those produced by S. cerevisiae. Furthermore, G. candidum has the potential to produce useful chemicals under appropriate culture conditions. [ABSTRACT FROM AUTHOR]

Enzymes are biocatalysts mainly used for their industrial potential in various applications. The present study aims to understand the enzyme production for biotechnological interest from a local yeast strain. From 100 isolates obtained from various biotopes, 78 strains were selected for their enzymatic heritage. Screening of a-amylase, lipase/esterase, and cellulase activities by rapid plate detection methods was carried out and the PO27 yeast was selected for its high capacity to produce a-amylase. In addition, this yeast strain exhibited good lipolytic and esterolytic activities, as well as low cellulase activity. A sequence analysis of the D1/D2 region of the 26S ribosomal RNA (26S rRNA) and a study of morphological characteristics identified the PO27 strain as Geotrichum candidum. The production of a-amylase has been studied in solid medium fermentation using various natural substrates without any supplementation such as olive pomace, potato peels, leftover bread, and mastic cake. G. candidum PO27 showed an improved production of a-amylase with olive pomace, thus reaching approximately 180.71 U/g. To evaluate the ability of this isolate to produce a-amylase in submerged fermentation, multiple concentrations of olive pomace substrate were tested. The best activity of submerged fermentation was statistically compared to the solid-state fermentation result in order to select the appropriate fermentation type. A high significant difference was found to rank the 6% olive pomace medium as the best substrate concentration with 34.395 U/mL of a-amylase activity. This work showed that the new isolate Geotrichum candidum PO27 has a better potential to produce a-amylase at a low cost in solid-state fermentation compared to submerged fermentation. Optimization conditions for PO27 a-amylase production through solid-state fermentation were achieved using a one factor at a time (OFAT) approach. The findings revealed that a high temperature (60 °), an acidic pH, malt extract, and soluble starch were the highly significant medium components for enhancing a-amylase production. The use of olive pomace waste by Geotrichum candidum PO27 is expected to be effective in producing an industrially useful a-amylase. [ABSTRACT FROM AUTHOR]

(1) Background: Agarwood is an aromatic resin produced by the host tree through an immunological response against biotic and abiotic stress. The aim was, first, to use the fungus Geotrichum candidum to stimulate compound changes in Aquilaria sinensis horizontally (color formation) and vertically (cutting layers) after injection with it. (2) Methods: Horizontal and vertical sections were collected and separated five months after injection with the fungal broth. Two grams of dry powder was mixed with 20 mL methanol for 3 h at room temperature, and the solution was vibrated in an ultrasonic cleaner bath at 40 °C for 1 h. After vacuum drying, a concentration of 10 mg/mL of the tested samples in methanol was prepared for reversed-phase high-performance liquid chromatography (RP-HPLC), gas chromatography/mass spectrometry (GC/MS), and thin-layer chromatography (TLC) analysis. (3) Results: The horizontal changes in the compounds and their concentrations were associated with color. Compared to the normal (N) group, G. candidum injection stimulated more compounds at RT 27–42 in the white (W) group, brown (BR) group, and black (B) group. Furthermore, a significant increase in fatty acids was observed in the W group, implying an early plant response after G. candidum injection. In the BR group, the compounds were more similar to commercial agarwood (Out group). In the B group, alkaloids were the main compounds. Vertical changes in the main compounds were not observed, although the compound level varied. A TLC analysis determined the main compounds in the BR group at 254 nm and in the B group at 365 nm. Higher fatty acid levels were found in L6 and L5 and were correlated with higher terpenoid and sesquiterpene levels, suggesting that these compounds were possibly the first stage of agarwood formation. A GC/MS analysis demonstrated that the main compound groups were almost identical to the BR parts. (4) Conclusions: The injection of G. candidum led A. sinensis to synthesize different phytochemicals horizontally, not vertically, in the BR group. [ABSTRACT FROM AUTHOR]

Background: Oral geotrichosis is an infection caused by Geotrichum species. It is an uncommon opportunistic oral fungal infection caused mainly by Geotrichum candidum and rarely found in immunocompetent hosts. This report attempted to highlight a case of unusual geotrichosis, which requires accurate observation, as well as indicate the appropriate diagnostic methods that may contribute to eliminating the misdiagnosis of this fungal infection. Case presentation: We report of unusual isolation of Geotrichum silvicola and Geotrichum candidum from the oral cavity of a 15-year-old immunocompetent female with a sign of oral geotrichosis. The isolation of Geotrichum silvicola and Geotrichum candidum was performed using Mitis Salivarius Agar. After a month of prescribing appropriate medication and improving oral hygiene, the patient showed the absence of all the signs of geotrichosis without any complaints and an improvement in overall oral health. Conclusions: The isolation of Geotrichum silvicola and Geotrichum candidum from the oral cavity of an immunocompetent patient is considered an unusual and rare case that documented for the first time. [ABSTRACT FROM AUTHOR]

Strains K2, Z7-1 and Z8-4, all of which could produce compounds that contribute to pleasant floral and fruity aromas, were isolated from kefir grains collected from Kumming, Yunnan. Based on genome resequencing, the genome similarity of the strains to Geotrichum candidum LMA-244 was analyzed, showing that the DNA-DNA hybridization values were 99.50%, 99.40% and 99.50%, and the average nucleotide identity was 98.66%, 98.65% and 98.68%, respectively. Based on morphological characteristics and 26S rDNA sequence homology analysis, all the strains were identified as G. candidum. Gene function annotation of G. candidum K2 was carried out using the Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and Cluster of Orthologous Group (COG) databases. The results showed that 40.74% of the annotated genes were associated with cellular components, 47.54% with biological processes and 11.73% with molecular functions. KEGG metabolic pathway analysis revealed the presence of genes and pathways related to terpenoid biosynthesis, indicating that G. candidum K2 has the genetic basis for the synthesis of volatile aroma components. By gas chromatography-mass spectrometry (GC-MS), a total of 50 volatile components were detected in the fermentation broth of G. candidum K2. Among them, 3-alkene, α-pinene and p-cymene contributed to the floral aroma, L-α-terpineol was responsible for the pine-like aroma, terpinen-4-ol and (-)-terpinen-4-ol was responsible for the clove-like aroma, and α-terpineol acetate contributed to the fresh and sweet aroma. Therefore, it was inferred that G. candidum greatly contributes to the formation of aroma substances in kefir grains. This study may provide a theoretical basis for the application of G. candidum K2 in fermented dairy products and other fermented foods.

The growth of two pairs of co-cultures (Escherichia coli/Geotrichum candidum and Staphylococcus aureus/Geotrichum candidum) with a starter culture of lactic acid bacteria was studied in milk at temperatures ranging from 15 °C to 21 °C, related to the ripening of artisanal cheese. For an inoculum of approximately 106 CFU/mL, LAB not only induced an early stationary phase of E. coli (two isolates BR and PS2) and S. aureus (isolates 2064 and 14733) but also affected their death phase. In co-cultures with LAB and G. candidum, the numbers of E. coli and S. aureus increased in 2 logs and 1 log, respectively, reaching maximum population densities (MPDs) of less than 5 and 4 logs, respectively. After that, the populations of both bacteria represented with two isolates decreased in more than 2 logs and 3 logs within 2 days compared to their MPDs, respectively. G. candidum was found to be the subject of interactions with LAB within a given temperature range only partially. To develop a tertiary model for the growth curves of the populations, a one-step approach was used, combining the Huang-Gimenez and Dalgaard primary model with secondary square-root models for growth rate and lag time. Furthermore, the reparametrized Gompertz-inspired function with the Bigelow secondary model was used to describe the death phase of the E. coli and S. aureus isolates. The prediction ability of the growth of the H-GD tertiary model for co-cultures was cross-validated within the isolates and datasets in milk and milk medium with 1% NaCl. The study can be used as knowledge support for the hygiene guidelines of short-ripened raw milk cheeses, as was our case in Slovakia. [ABSTRACT FROM AUTHOR]

Palm kernel cake (PKC), a byproduct of palm oil extraction, serves an important role in Ecuador’s animal feed industry. The emergence of yellow-orange fungal growth in PKC on some cattle farms in Ecuador sparked concerns within the cattle industry regarding a potential mycotoxin-producing fungus on this substrate. Due to the limited availability of analytical chemistry techniques in Ecuador for mycotoxin detection, we chose to isolate and identify the fungus to determine its association with mycotoxin-producing genera. Through molecular identification via ITS region sequencing, we identified the yellow-orange fungus as the yeast Candida ethanolica. Furthermore, we isolated two other fungi—the yeast Pichia kudriavzevii, and the fungus Geotrichum candidum. Molecular identification confirmed that all three species are not classified as mycotoxin-producing fungi but in contrast, the literature indicates that all three have demonstrated antifungal activity against Aspergillus and Penicillium species, genera associated with mycotoxin production. This suggests their potential use in biocontrol to counter the colonization of harmful fungi. We discuss preventive measures against the fungal invasion of PKC and emphasize the importance of promptly identifying fungi on this substrate. Rapid recognition of mycotoxin-producing and pathogenic genera holds the promise of mitigating cattle intoxication and the dissemination of mycotoxins throughout the food chain.

To better understand its mechanism of activity towards higher alcohols, we overexpressed and purified new Geotrichum candidum GDH (GcGDH). The purified GcGDH (50.27 kDa) was then crystallized, and the crystal diffracted to a resolution of 2.3 Å using X-ray diffraction. We found that the GcGDH crystal structure belonged to space group P212121 and was comprised of two hexamers organized into an asymmetric unit, with each subunit consisting of 452 amino acid residues. The binding sites between higher alcohols or L-glutamic acid and GcGDH were consistent. The optimal reaction conditions for GcGDH and hexanol were a pH of 4.0 and temperature of 30 °C, and those for GcGDH and monosodium glutamate (MSG) were a pH of 8.0 and temperature of 20 °C. The Km values for hexanol and MSG were found to be 74.78 mM and 0.018 mM, respectively. Mutating GcGDH Lys 113 to either Ala or Gly caused a dramatic reduction in its catalytic efficiency towards both MSG and hexanol, suggesting that Lys 113 is essential to the active site of GcGDH. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Mold‐ripened cheeses have low levels of unsaturated fatty acids (UFAs). Geotrichum candidum is an adjunct culture for the development of Geotrichum‐ripened cheese but has a low ability to produce high levels of UFAs. Δ12 fatty acid desaturase (FADS12) is a pivotal enzyme that converts oleic acid (OA) to linoleic acid (LA) and plays a vital role in UFA biosynthesis. By investigating FADS12 catalytic activity from various species with OA substrates, we found that FADS12 from Mucor circinelloides (McFADS12) had the highest catalytic activity for OA. RESULTS: In the current study, a plasmid harboring McFADS12 was constructed and overexpressed in G. candidum. Our results showed that LA production increased to 31.1 ± 1.4% in engineered G. candidum – three times higher than that in wild‐type G. candidum. To enhance LA production, an exogenous substrate (OA) was supplemented, and the yield of LA was increased to 154 ± 6 mg L−1 in engineered G. candidum. Engineered G. candidum was used as an adjunct culture for Geotrichum‐ripened cheese production. The LA level reached 74.3 ± 5.4 g kg−1 cheese, whereas the level of saturated fatty acids (SFAs) decreased by 9.9 ± 0.5%. In addition, the soybean byproduct (okara) was introduced into the engineered G. candidum growth and the level of LA increased to 126 ± 4 g kg−1 cheese and the percentage of UFAs:SFAs increased from 0.8:1 to 1.3:1. CONCLUSION: This study offers a suitable technology for converting SFAs to UFAs in Geotrichum‐ripened cheeses and provides a novel trend for converting soybean waste into a value‐added product. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Fungi make a fundamental contribution to several biotechnological processes, including brewing, winemaking, and the production of enzymes, organic acids, alcohols, antibiotics, and pharmaceuticals. The present review explores the biotechnological importance of the filamentous yeast-like fungus Geotrichum candidum, a ubiquitous species known for its use as a starter in the dairy industry. To uncover G. candidum's biotechnological role, we performed a search for related work through the scientific indexing internet services, Web of Science and Google Scholar. The following query was used: Geotrichum candidum, producing about 6500 scientific papers from 2017 to 2022. From these, approximately 150 that were associated with industrial applications of G. candidum were selected. Our analysis revealed that apart from its role as a starter in the dairy and brewing industries, this species has been administered as a probiotic nutritional supplement in fish, indicating improvements in developmental and immunological parameters. Strains of this species produce a plethora of biotechnologically important enzymes, including cellulases, β-glucanases, xylanases, lipases, proteases, and α-amylases. Moreover, strains that produce antimicrobial compounds and that are capable of bioremediation were identified. The findings of the present review demonstrate the importance of G. candidum for agrifood- and bio-industries and provide further insights into its potential future biotechnological roles. [ABSTRACT FROM AUTHOR]

During the postharvest period, citrus fruits are exposed to Penicillium italicum, Penicillium digitatum, and Geotrichum candidum. Pesticides such as imazalil (IMZ), thiabendazole (TBZ), orthophenylphenol (OPP), and guazatine (GUA) are commonly used as antifungals. Glyphosate (GP) is also used in citrus fields to eliminate weed growth. The sensitivity of fungal pathogens of citrus fruit to these pesticides and 1,8-cineole was evaluated, and the effect of GP on the development of cross-resistance to other chemicals was monitored over a period of 3 weeks. IMZ most effectively inhibited the mycelial growth and spore germination of P. digitatum and P. italicum, with minimum inhibitory concentrations (MICs) of 0.01 and 0.05 mg/mL, respectively, followed by 1,8-cineole, GP, and TBZ. 1,8-Cineole and GP more effectively inhibited the mycelial growth and spore germination of G. candidum, with minimum inhibitory concentrations (MICs) of 0.2 and 1.0 mg/mL, respectively, than OPP or GUA. For the spore germination assay, all substances tested showed a total inhibitory effect. Subculturing the fungal strains in culture media containing increasing concentrations of GP induced fungal tolerance to GP as well as to the fungicides. In soil, experiments confirmed that GP induced the tolerance of P. digitatum to TBZ and GP and the tolerance of P. italicum to IMZ, TBZ, and GP. However, no tolerance was recorded against 1,8-cineole. In conclusion, it can be said that 1,8-cineole may be recommended as an alternative to conventional fungicides. In addition, these results indicate that caution should be taken when using GP in citrus fields. [ABSTRACT FROM AUTHOR]

There is great potential to remediate heavy metal contaminated environments through bioaugmentation with filamentous fungi. However, these fungi have been poorly investigated in most developing countries, such as Zambia. Therefore, the present study aimed at isolating indigenous filamentous fungi from heavy metal contaminated soil and to explore their potential for use in bioaugmentation. The conventional streak plate method was used to isolate fungi from heavy metal-contaminated soil. Filamentous fungal isolates were identified using morphological and molecular techniques. The radial growth diameter technique was used to evaluate heavy metal tolerance of the fungi. The most abundant and highly tolerant fungi, identified as Aspergillus transmontanensis, Cladosporium cladosporioides, and Geotrichum candidum species, were used to bioremediate heavy metal contaminated soil samples with uncontaminated soil sample being employed as a control. A maximum tolerance index (TI) between 0.7 and 11.0 was observed for A. transmontanensis, and G. candidum while C. cladosporioides displayed the TI between 0.2 and 1.2 in the presence of 1,000 ppm of Cu, Co, Fe, Mn, and Zn. The interspecific interaction was analyzed to determine the compatibility among isolates. Our results showed mutual intermingling between the three evaluated fungal species, which confirms their common influence in biomineralization of heavy metals in contaminated soils. Maximum bio-removal capacities after 90 days were 72% for Cu, 99.8% for Co, 60.6% for Fe, 82.2% for Mn, and 100% for both Pb and Zn. This study has demonstrated the potential of highly resistant autochthonous fungal isolates to remediate the heavy metal contamination problem. [ABSTRACT FROM AUTHOR]

Geotrichum candidum Link is one of the prevailing microfungi in the dairy industry. Mentioned species are characterized with high energy of growth at wide range of pH and temperature. It possess proteolytic and lypolitic activity, thus causes the critical decrease of dairy products quality at very short time periods. On the other hand G. candidum is widely used in cheese making industry for processing of "Camembert" and "Brie". Due to high antagonistic activity it prevents the growth of opportunistic pathogenic and pathogenic bacteria in cheese in some measure. The main objective of the presented work was to investigate the prevalence of G. candidum in cottage cheese and possibilities of using its metabolites in dairy industry as a biopreservative. 10 samples of cottage cheese from different Armenian dairy industry companies have been analyzed. More than 27 strains of G. candidum have been isolated from cottage cheese using the glucose-yeast extractchloramphenicol agar and the macro and micro morphological criteria at different selective media were studied (by ISO 6611 and IDF 94). The dynamics of their growth has been studied in modified Chapek-Dox broth (HiMedia, M076) at different temperatures (25 °C, 30 °C, and 37 °C) and incubation times. Antibacterial activity was investigated against Staphylococcus aureus ATCC 6538, E. coli K12 DSM498 and Enterobacter aerogenes ATCC 13048 by well-diffusion method on Mueller-Hinton agar (MHA) in accordance with (CLSI, [42]). The maximal synthesis of metabolites which possessed high antibacterial activity occurred at 30 0° on 3rd day of incubation and pH values 3.35 - 3.45. The optimal conditions for producing of metabolites which possessed high antibacterial activity against Staphylococcus aureus ATCC 6538 have been developed. G. candidum can be a potential source of biopreservative used for prevention of growth and toxin formation of opportunistic bacteria, including staphylococci in cottage cheese and other dairy products. In this context, the application of metabolites G. candidum as natural biological antagonists may represent a promising alternative to the chemical preservation. [ABSTRACT FROM AUTHOR]

There is great potential to remediate heavy metal contaminated environments through bioaugmentation with filamentous fungi. However, these fungi have been poorly investigated in most developing countries, such as Zambia. Therefore, the present study aimed at isolating indigenous filamentous fungi from heavy metal contaminated soil and to explore their potential for use in bioaugmentation. The conventional streak plate method was used to isolate fungi from heavy metal-contaminated soil. Filamentous fungal isolates were identified using morphological and molecular techniques. The radial growth diameter technique was used to evaluate heavy metal tolerance of the fungi. The most abundant and highly tolerant fungi, identified as Aspergillus transmontanensis, Cladosporium cladosporioides, and Geotrichum candidum species, were used to bioremediate heavy metal contaminated soil samples with uncontaminated soil sample being employed as a control. A maximum tolerance index (TI) between 0.7 and 11.0 was observed for A. transmontanensis, and G. candidum while C. cladosporioides displayed the TI between 0.2 and 1.2 in the presence of 1,000 ppm of Cu, Co, Fe, Mn, and Zn. The interspecific interaction was analyzed to determine the compatibility among isolates. Our results showed mutual intermingling between the three evaluated fungal species, which confirms their common influence in biomineralization of heavy metals in contaminated soils. Maximum bio-removal capacities after 90 days were 72% for Cu, 99.8% for Co, 60.6% for Fe, 82.2% for Mn, and 100% for both Pb and Zn. This study has demonstrated the potential of highly resistant autochthonous fungal isolates to remediate the heavy metal contamination problem.

The growth of two pairs of co-cultures (Escherichia coli/Geotrichum candidum and Staphylococcus aureus/Geotrichum candidum) with a starter culture of lactic acid bacteria was studied in milk at temperatures ranging from 15 °C to 21 °C, related to the ripening of artisanal cheese. For an inoculum of approximately 106 CFU/mL, LAB not only induced an early stationary phase of E. coli (two isolates BR and PS2) and S. aureus (isolates 2064 and 14733) but also affected their death phase. In co-cultures with LAB and G. candidum, the numbers of E. coli and S. aureus increased in 2 logs and 1 log, respectively, reaching maximum population densities (MPDs) of less than 5 and 4 logs, respectively. After that, the populations of both bacteria represented with two isolates decreased in more than 2 logs and 3 logs within 2 days compared to their MPDs, respectively. G. candidum was found to be the subject of interactions with LAB within a given temperature range only partially. To develop a tertiary model for the growth curves of the populations, a one-step approach was used, combining the Huang-Gimenez and Dalgaard primary model with secondary square-root models for growth rate and lag time. Furthermore, the reparametrized Gompertz-inspired function with the Bigelow secondary model was used to describe the death phase of the E. coli and S. aureus isolates. The prediction ability of the growth of the H-GD tertiary model for co-cultures was cross-validated within the isolates and datasets in milk and milk medium with 1% NaCl. The study can be used as knowledge support for the hygiene guidelines of short-ripened raw milk cheeses, as was our case in Slovakia.

Citriculture is an important economic activity worldwide and for decades, this sector has been responsible for creating job opportunities. Currently, Brazil is the largest orange producer in the world, which contributes to the country's economy. However, citrus production has been facing several issues that compromise the quality of the fruits. For instance, several postharvest diseases occur during storage and transportation, directly harming product marketing. Green mold, blue mold, and sour rot are considered the most common postharvest citrus diseases. Citrus sour rot is less common; however, the disease can lead to a significant loss in high rainfall seasons. The fungus Geotrichum candidum is the causal agent of sour rot and its chemical and biochemical infection strategies are still little explored in citrus fruits. Several conventional control methods, including the application of fungicides, aim to contain the disease proliferation, but most of the commercially available fungicides are not efficient against sour rot. For this reason, other strategies have been studied for disease control, such as chemicals (e. g. essential oils or other natural products), biological agents used as biocontrol, and physical strategies. Despite its importance, few reviews have focused on sour rot disease. Here, we summarize the biochemical aspects of G. candidum, as well as the metabolites produced by this phytopathogen, the known virulence factors, and advances for disease management. • Postharvest diseases such as green mold, blue mold, and sour rot occur during storage and transportation, directly harming product marketing. • Citrus sour rot is responsible for a significant loss in high rainfall seasons. The sour rot causal agent, the fungus Geotrichum candidum , has been little explored in its biochemical perspectives. The chemical and biochemical aspects of the disease are reviewed. • Several approaches for disease control including chemical, biological agents, and physical strategies have been applied both in the fields and in research studies to improve sour rot management. [ABSTRACT FROM AUTHOR]

Aim: The aroma-producing strain of Geotrichum candidum GDMCC60675 was taken as the research object, the composition of aroma-producing substances of G. candidum was studied, and the target strains of G. candidum suitable for food additives were screened out by mutagenesis. Methods: Mutants were obtained by space breeding. The colony morphology and cell morphology of the mutant strain were identified, the phylogenetic tree of the two strains was constructed, and the whole-genome sequences of the wild strain and the mutant strain were compared. The aroma components and key odor compounds of the two strains were analyzed and compared by HS-SPME-GC-MS and E-nose detection, and the data were processed by using the relative odor activity value (ROAV) analysis method. Results: A mutant strain of G. candidum was found with different characteristics of aroma production compared with wild-type G. candidum. It was found that its colony morphology and cell morphology were similar. However, it was found that the aroma-producing substances produced by the two strains were different, and the key difference compound was phenyl ethyl alcohol, which also proved that the two strains were different, and the main aroma note was different. [ABSTRACT FROM AUTHOR]

To better understand its mechanism of activity towards higher alcohols, we overexpressed and purified new Geotrichum candidum GDH (GcGDH). The purified GcGDH (50.27 kDa) was then crystallized, and the crystal diffracted to a resolution of 2.3 Å using X-ray diffraction. We found that the GcGDH crystal structure belonged to space group P212121 and was comprised of two hexamers organized into an asymmetric unit, with each subunit consisting of 452 amino acid residues. The binding sites between higher alcohols or L-glutamic acid and GcGDH were consistent. The optimal reaction conditions for GcGDH and hexanol were a pH of 4.0 and temperature of 30 °C, and those for GcGDH and monosodium glutamate (MSG) were a pH of 8.0 and temperature of 20 °C. The Km values for hexanol and MSG were found to be 74.78 mM and 0.018 mM, respectively. Mutating GcGDH Lys 113 to either Ala or Gly caused a dramatic reduction in its catalytic efficiency towards both MSG and hexanol, suggesting that Lys 113 is essential to the active site of GcGDH.

Fungi make a fundamental contribution to several biotechnological processes, including brewing, winemaking, and the production of enzymes, organic acids, alcohols, antibiotics, and pharmaceuticals. The present review explores the biotechnological importance of the filamentous yeast-like fungus Geotrichum candidum, a ubiquitous species known for its use as a starter in the dairy industry. To uncover G. candidum’s biotechnological role, we performed a search for related work through the scientific indexing internet services, Web of Science and Google Scholar. The following query was used: Geotrichum candidum, producing about 6500 scientific papers from 2017 to 2022. From these, approximately 150 that were associated with industrial applications of G. candidum were selected. Our analysis revealed that apart from its role as a starter in the dairy and brewing industries, this species has been administered as a probiotic nutritional supplement in fish, indicating improvements in developmental and immunological parameters. Strains of this species produce a plethora of biotechnologically important enzymes, including cellulases, β-glucanases, xylanases, lipases, proteases, and α-amylases. Moreover, strains that produce antimicrobial compounds and that are capable of bioremediation were identified. The findings of the present review demonstrate the importance of G. candidum for agrifood- and bio-industries and provide further insights into its potential future biotechnological roles.

Fungi are one of the most important groups of marine microorganisms used to produce important enzymes and antimicrobials. Industrially, the cellulase produced from marine fungi plays an impotent role; however, using it medically is very limited. Hence, this study aimed to use purified and characterized cellulase enzymes produced from Geotrichum candidum strain Gad1 to determine their antimicrobial and antifouling activities. The maximum cellulase activity was achieved (55.54 U/ml) with maximum specific activities (325.8 U/mg). The highest antimicrobial activity of cellulase was 42 mm diameter of zone inhibition found against Vibrio damsel as antibacterial, and 19 mm diameter of zone inhibition observed against Aspergillus niger as an antifungal. By using 600 ul/l of cellulase, the high reduction of the bacterial load in the formed biofilm was shown. The data obtained during the present study confirmed the potential of fungal cellulase. The cellulase enzyme produced by G. candidum strain Gad1 demonstrated promising antibacterial, antifungal and antifouling properties. [ABSTRACT FROM AUTHOR]

Copyright of Ziemniak Polski is the property of Instytutem Hodowli & Aklimatyzacji Roslin - Panstwowym Instytutem Badawczym and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background Antibiotic resistance and dearth of novel compounds from natural sources warrants the need to search other environments for potential antibiotic-producing microbial species. The study investigated isolation and identification of antibiotic-producing fungi from pharmaceutical waste sludge. Results Seven hundred and ninety-seven isolates obtained from sludge of seven pharmaceutical industries in Sango Ota, Ogun State using several growth media, with mould isolates highest (696). Isolated species were from genera Aspergillus (28.55%), Penicillium (18.35%), Trichoderma (13.44%), Rhizopus (10.21%) and Geotrichum (4.01%), and Stachybotrys (0.13%). The CFS of strains named Geotrichum candidum OMON-1, Talaromyces pinophilus OKHAIN-12, and Penicillium citrinum PETER-OOA1 had high reproducible bioactivity against Staphylococcus aureus (32 ± 0.12 mm) and Klebsiella pneumoniae (29 ± 0.12 mm) while P. citrinum MASTER-RAA2 had activity against K. pneumoniae only. Active metabolites were successfully extracted using Diaion HP-20 and methanol:iso-propanol:acetone (6:3:1 v/v). Antibacterial-active fractions of fungal extract successfully eluted with 40–60% NaCl on ion-exchange chromatography using a cation column. Conclusions The study successfully screened antibiotic-producing fungal species from pharmaceutical waste storage facilities. Study also showed that similar species from same toxic environment could potentially produce different metabolites.

Production of high-quality and microbiologically safe fermented dairy products requires controlled growth and microbial interactions between lactic acid bacteria and microscopic fungi. For this purpose, detailed knowledge of their growth characteristics is needed. Therefore, the objective of this study was to analyse the growth dynamics of lactic acid bacteria of commercial DVS® FRESCO® 1000NG culture and dairy isolate of microscopic fungus Geotrichum candidum during their co-cultivation in milk. The growth dynamics of microorganisms was studied in dependence on their initial counts at 12, 15, 18, 21 and 30 °C. Growth parameters were calculated by two primary predictive models, model of Baranyi and Roberts and Huang's model. Both models showed good ability to describe the growth dynamics of studied microorganisms, as it was confirmed by low values of RMSE index. Both microbial cultures, Fresco culture and Geotrichum candidum, showed good growth ability in milk since they reached the average maximum density of 9.50 ± 0.13 log CFU/mL and 5.85 ± 0.69 log CFU/mL (n = 45), in order. Maximum density of studied microorganisms was not affected by their initial counts or incubation temperature. On the other hand, effect of mutual ratio of microbial initial counts and increasing temperature had a significant impact on growth dynamics. [ABSTRACT FROM AUTHOR]

Cellulose fibers were extracted from sugarcane bagasse and then modified with ZnO nanoparticles (NPs) by a sol-gel process using an oxime modified Zn precursor [ZnCl2.2{HONC(CH3)2}] in different gram ratios to make them antimicrobial. ZnO modified cellulose fibers were further characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) studies. Obtained results confirmed well-dispersed hexagonal wurtzite ZnO NPs onto the surface of cellulose. Lower band gaps (2.87-2.48 eV) were observed in ZnO modified cellulose as compared to pure ZnO NPs (~ 3.3 eV). Antibacterial activities were examined against Staphylococcus aureus and Escherichia coli in different ratios (1:1, 1:2 and 1:3) and concentrations (1.5 to 200 mg·ml-1) of ZnO modified cellulose. The antifungal activity of ZnO modified cellulose (1:1) was evaluated against Aspergillus niger, Phanerochaete chrysosporium, and Geotrichum candidum. ZnO modified cellulose ratio of 1:1 at the tested concentration remarkably inhibited the mycelial growth of the fungus. The antifungal efficacy of ZnO modified cellulose depended on the concentration of the sample concerned, therefore maximal inhibition of mycelia growth occurred at the highest concentration (5 mg). [ABSTRACT FROM AUTHOR]

Globally, textile industries are one of the major sectors releasing dye pollutants. This is the first report on the positive correlation between toxicity and chemical oxygen demand (COD) of textile effluent along with the proposed pathway for enzymatic degradation of acid orange 10 using Geotrichum candidum within a very short stretch of time (18 h). Removal efficiency of this mycoremedial approach after 18 h in terms of chemical oxygen demand, biological oxygen demand, total suspended solids, salinity, color and dye concentration in the treated effluent reached to 98.5%, 56.3%,73.2%, 64%, 89% and 87% respectively. Also there was a decrease in pH of the treated effluent. FTIR analysis of the treated effluent confirmed biodegradation. The LCMS analysis showed the degradation of acid orange 10, which was confirmed by the formation of two biodegradation products, 7-oxo-8-iminonapthalene-1,3-disulfonate and nitrosobenzene, which subsequently undergoes stepwise hydrogenation and dehydration to form aniline via phenyl hydroxyl amine as intermediate. The X-ray diffraction studies showed that heavy metal content in the treated effluent has reduced along with decrease in % crystallinity, indicating biodegradation. The connection between toxicity and COD was also inveterated using Pearson's correlation coefficient. Further the toxicological studies indicated the toxicity of raw textile effluent and relatively lower toxic nature of metabolites generated after biodegradation by G. candidum. [ABSTRACT FROM AUTHOR]

The present study was held to optimize production, purify and identify biosurfactant from yeast strain Geotrichum candidum MK880487. Biosurfactant production was done on modified Hua medium and optimized in shake-flask method. Soybean oil (8%, v/v), KNO3 (0.75 g L−1) and yeast extract (0.3 g L−1) were the best carbon and nitrogen sources, respectively, with C:N ratio of 200:1, pH 8 at 30 °C for 168 h. Production scale-up was achieved on 2.5 L bioreactor as batch method. The resulting crude biosurfactant extract with yield of 1.75 g L−1 was purified by reversed phase column preparative HPLC. The resulting most active fraction F47 significantly reduced water surface tension by 51.92%. Chemical characterization using TLC, GC-MS, FTIR and LC-MS/MS methods revealed the biosurfactant to contain mainly glycolipid structure existing as mixture of Icariside F2, Cardenolide Di-Hexopyranoside and Di Galactosyl Di Acyl Glycerol glycolipid that collectively showed potential antifungal activity toward Macrophomina phaseolina. Process flow scheme of this study showing the BS production scale up, separation, purification, identification and application as antifungal agent. [ABSTRACT FROM AUTHOR]

The study of microbial growth in relation to food environments provides essential knowledge for food quality control. With respect to its significance in the dairy industry, the growth of Geotrichum candidum isolate J in milk without and with 1% NaCl was investigated under isothermal conditions ranging from 6 to 37 °C. The mechanistic model by Baranyi and Roberts was used to fit the fungal counts over time and to estimate the growth parameters of the isolate. The effect of temperature on the growth of G. candidum in milk was modelled with the cardinal models, and the cardinal temperatures were calculated as Tmin = −3.8–0.0 °C, Topt = 28.0–34.6 °C, and Tmax = 35.2–37.2 °C. The growth of G. candidum J was slightly faster in milk with 1% NaCl and in temperature regions under 21 °C. However, in a temperature range that was close to the optimum, its growth was slightly inhibited by the lowered water activity level. The present study provides useful cultivation data for understanding the behaviour of G. candidum in milk and can serve as an effective tool for assessing the risk of fungal spoilage, predicting the shelf life of dairy products, or assessing the optimal conditions for its growth in relation to the operational parameters in dairy practices. [ABSTRACT FROM AUTHOR]

Textile effluent is generally complicated to manage because of its extremely noxious and recalcitrant coloured compositions. Mycoremediation is an extensively used strategy for the competent degradation of hazardous pollutants present in textile effluent. Fungus could be immobilized in synthetic or natural matrices. The current study shows the decolourization of the textile effluent by 85·5 and 98·5% within 6 h using suspended and immobilized fungus, Geotrichum candidum with optimized parameters like inoculum size (5%), pH (4·5), and temperature (30°C). To maintain a high biomass of fungal population and enhance the retention of fungal strain in the contaminated sites, the fungi need to be immobilized. Hence, the fungus was immobilized naturally onto the selected inert support that is, coconut fibres by the means of adsorption, where they grew as active films on the fibres after being grown in the culture broth. The optimized process parameters of inoculum size, fibre quantity and agitation speed for immobilized G. candidum were 5%, 2·2 g l−1 of effluent and 100 rev min−1 respectively. High level of laccase (22 and 25 U l−1 in suspended and immobilized fungal cells treatment respectively) was observed during the process of decolourization and it was found that decolourization was directly proportional to the laccase activity. The UV–vis, FTIR, 1H NMR and GC‐MS analyses of treated textile industrial wastewater revealed the degradation of toxic pollutants in the textile effluent and formation of lower molecular weight intermediates. The study revealed a higher efficacy of immobilized G. candidum in comparison to suspended fungal culture, employing ligninolytic enzyme laccase, which catalyzes the degradation/transformation of aromatic dyes in the textile effluent thus decolourizing it. [ABSTRACT FROM AUTHOR]

The wide scale application of pectinase is generally hindered by high cost of the enzyme production. In this work, a two dimensional strategy was adopted to reduce cost of pectinase production by Geotrichum candidum AA15. The strain was immobilized in alginate beads. The optimum concentration for bead formation was found to be 3.5% of sodium alginate (NA) with 4% calcium chloride (CaCl2). Such immobilized cells retained the ability to produce 0.115 IU mL−1 of pectinase for up to 6th production cycle in citrus pectin containing medium while free cells produced only 0.046 IU mL−1 of pectinase. For the cultivation of immobilized cells on orange peels (OP), a combination of 4.5% NA and 4% CaCl2 was found effective to prepare beads. Geotrichum candidum AA15 produced 0.220 IU mL−1 pectinase by fermenting OP as a substrate for up to 3rd production cycle. The results revealed that the process of immobilization can be used as a promising strategy in combination with the use of naturally available waste biomass.

The yeast Geotrichum candidum (teleomorph Galactomyces candidus) is inoculated onto mold- and smear-ripened cheeses and plays several roles during cheese ripening. Its ability to metabolize proteins, lipids, and organic acids enables its growth on the cheese surface and promotes the development of organoleptic properties. Recent multilocus sequence typing (MLST) and phylogenetic analyses of G. candidum isolates revealed substantial genetic diversity, which may explain its strain-dependant technological capabilities. Here, we aimed to shed light on the phenotypic and genetic diversity among eight G. candidum and three Galactomyces spp. strains of environmental and dairy origin. Phenotypic tests such as carbon assimilation profiles, the ability to grow at 35°C and morphological traits on agar plates allowed us to discriminate G. candidum from Galactomyces spp. The genomes of these isolates were sequenced and assembled; whole genome comparison clustered the G. candidum strains into three subgroups and provided a reliable reference for MLST scheme optimization. Using the whole genome sequence as a reference, we optimized an MLST scheme using six loci that were proposed in two previous MLST schemes. This new MLST scheme allowed us to identify 15 sequence types (STs) out of 41 strains and revealed three major complexes named GeoA, GeoB, and GeoC. The population structure of these 41 strains was evaluated with STRUCTURE and a NeighborNet analysis of the combined six loci, which revealed recombination events between and within the complexes. These results hint that the allele variation conferring the different STs arose from recombination events. Recombination occurred for the six housekeeping genes studied, but most likely occurred throughout the genome. These recombination events may have induced an adaptive divergence between the wild strains and the cheesemaking strains, as observed for other cheese ripening fungi. Further comparative genomic studies are needed to confirm this phenomenon in G. candidum. In conclusion, the draft assembly of 11 G. candidum/Galactomyces spp. genomes allowed us to optimize a genotyping MLST scheme and, combined with the assessment of their ability to grow under different conditions, provides a reliable tool to cluster and eventually improves the selection of G. candidum strains.

Lipase is an enzyme commonly used in food, dairy, and other industries. Fungal lipases are more commonly used due to their secretion and easier production. Analyses of the amino acid composition of microbial lipases will hasten their potential usage in industrial applications. In this study, the major amino acid compositions of lipases secreted by oil pollutant isolates (Cunninghamella verticillata and Geotrichum candidum) enriched with fatty substances were analyzed by high performance liquid chromatography. Among eight major amino acids found in these lipases, histidine and ornithine were predominant. Lysine was absent from lipase generated by C. verticillata, while glutamine was absent from that produced by G. candidum. Conversely, glutamic acid, asparagine, histidine and arginine were present in slightly higher amounts in G. candidum. However, a slight decrease in aspartic acid and ornithine was observed in G. candidum. Analyses of the amino acids composition of lipase can potentially facilitate to predict the nature of this enzyme.

BACKGROUND Lignocellulosic wastes are pretreated prior to their utilization in fermentation processes. Such pretreatment also alters the topological features of the substrates, and therefore the suitability of pretreated waste as immobilization matrix for microbial cells needs investigation. RESULTS: In this study, the effect of chemical pretreatment of sugarcane bagasse (SB) for its subsequent utilization as a matrix to immobilize a pectinolytic yeast, Geotrichum candidum AA15, was evaluated using cell retention, concentration of immobilized cells, immobilization efficiency, scanning electron microscopy and Fourier transform infrared spectroscopy of the substrate and pectinase titers obtained after recycling. The results revealed that untreated SB is more efficient for immobilization with higher values of cell retention and pectinase productivity (99.78%) retained for up to six production cycles. It was deduced that removal of lignin by pretreatment negatively influenced the ability of SB to support cell adhesion, as lignin acts as a sealing agent that provides strength to the substrate. CONCLUSIONS: The strategy of utilizing SB as immobilization matrix was found effective at the laboratory scale as it improved pectinase production and may be investigated further for large‐scale and cost‐effective production. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agriculture & Nature / Kahramanmaraş Sütçü İmam Üniversitesi Tarım & Doğa Dergisi is the property of Kahramanmaras Sutcu Imam Universitesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)