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Microalgae biomass is considered an important feedstock for biofuels and other bioactive compounds due to its faster growth rate, high biomass production and high biomolecules accumulation over first and second-generation feedstock. This research aimed to maximize the specific growth rate of fresh water green microalgae Closteriopsis acicularis, a member of family Chlorellaceae under the effect of pH and phosphate concentration to attain enhanced biomass productivity. This study investigates the individual and cumulative effect of phosphate concentration and pH on specific growth characteristics of Closteriopsis acicularis in autotrophic mode of cultivation for bioethanol production. Central-Composite Design (CCD) strategy and Response Surface Methodology (RSM) was used for the optimization of microalga growth and ethanol production under laboratory conditions. The results showed that high specific growth rate and biomass productivity of 0.342 day−1 and 0.497 g L−1 day−1 respectively, were achieved at high concentration of phosphate (0.115 g L−1) and pH (9) at 21st day of cultivation. The elemental composition of optimized biomass has shown enhanced elemental accumulation of certain macro (C, O, P) and micronutrients (Na, Mg, Al, K, Ca and Fe) except for nitrogen and sulfur. The Fourier transform infrared spectroscopic analysis has revealed spectral peaks and high absorbance in spectral range of carbohydrates, lipids and proteins, in optimized biomass. The carbohydrates content of optimized biomass was observed as 58%, with 29.3 g L−1 of fermentable sugars after acid catalyzed saccharification. The bioethanol yield was estimated as 51 % g ethanol/g glucose with maximum of 14.9 g/L of bioethanol production. In conclusion, it can be inferred that high specific growth rate and biomass productivity can be achieved by varying levels of phosphate concentration and pH during cultivation of Closteriopsis acicularis for improved yield of microbial growth, biomass and bioethanol production.

Electronic waste is termed as e-waste and on recycling it produces environmental pollution. Among these e-waste pollutants, polychlorinated biphenyls (PCBs) are significantly important due to ubiquitous, organic in nature and serious health and environmental hazards. PCBs are used in different electrical equipment such as in transformers and capacitors for the purposes of exchange of heat and hydraulic fluids. Bioremediation is a reassuring technology for the elimination of the PCBs from the environment. In spite of their chemical stability, there are several microbes which can bio-transform or mineralize the PCBs aerobically or anaerobically. In this review paper, our objective was to summarize the information regarding PCB-degrading enzymes and microbes. The review suggested that the most proficient PCB degraders during anaerobic condition are Dehalobacter, Dehalococcoides, and Desulfitobacterium and in aerobic condition are Burkholderia, Achromobacter, Comamonas, Ralstonia, Pseudomonas, Bacillus, and Alcaligenes etc., showing the broadest substrate among bacterial strains. Enzymes found in soil such as dehydrogenases and fluorescein diacetate (FDA) esterases have the capability to breakdown PCBs. Biphenyl upper pathway involves four enzymes: dehydrogenase (bphB), multicomponent dioxygenase (bphA, E, F, and G), second dioxygenase (bphC), hydrolase, and (bphD). Biphenyl dioxygenase is considered as the foremost enzyme used for aerobic degradation of PCBs in metabolic pathway. It has been proved that several micro-organisms are responsible for the PCB metabolization. The review provides novel strategies for e-waste-contaminated soil management.

Anaerobic digestion is a sustainable approach to deal with wastes with beneficial production of sustainable energy. In the anaerobic digestion processes, an increase in ammonia concentration hinders the efficacy of biogas production. The current study focused on minimizing the ammonia effect by the addition of zeolite as an adsorbent in a fluidized bed anaerobic reactor using poultry slaughterhouse waste as the substrate. The effects of zeolite dosage were investigated at mesophilic and thermophilic temperatures. Biomethane potential, volatile solids reduction, chemical oxygen demand, total volatile fatty acids concentration, ammonia–nitrogen levels, and pH were monitored. The initial biomethane potential test revealed that poultry slaughterhouse waste produces methane for up to 610 ml/g volatile solids (intestinal residues) and 200 ml/g volatile solids (feathers) at mesophilic conditions, 675 ml/g volatile solids (intestinal residues) and 276 ml/g volatile solids (feathers) at thermophilic conditions. The amendment with zeolite had significantly reduced chemical oxygen demand for up to 57%. Volatile solids reduction increased from 13 to 19%. Ammonia–nitrogen concentrations also decreased (15.5 mg/l) due to the application of zeolite. Enhanced biogas production of 700 ml/g volatile solids was observed after 25 days. It can be concluded that the addition of zeolite can significantly enhance biogas production by reducing the ammonia concentration in anaerobic digesters.

Benzoic acid (BA) is potentially toxic to humans and recalcitrant in the environment. Although it may be degraded by fungi, potential degradation pathways has received limited study. In the present...

Organophosphates (OPs) are neurotoxic agents also used as pesticides that can permanently block the active site of the acetylcholinesterase (AChE). A robust and sensitive detection system of OPs utilising the enzyme mimic potential of the cysteamine capped gold nanoparticles (C-AuNPs) was developed. The detection assay was performed by stepwise addition of AChE, parathion ethyl (PE)-a candidate OP, acetylcholine chloride (ACh), C-AuNPs, and 3, 3′, 5, 5′-tetramethylbenzidine (TMB) in the buffer solution. The whole sensing protocol completes in 30–40 min, including both incubations. The Transmission Electron Microscopy (TEM) results indicated that the NPs are spherical and have an average size of 13.24 nm. The monomers of C-AuNPs exhibited intense catalytic activity (nanozyme) for the oxidization of TMB, revealed by the production of instant blue colour and confirmed by a sharp peak at 652 nm. The proposed biosensor’s detection limit and linear ranges were 5.8 ng·mL−1 and 11.6–92.8 ng·mL−1, respectively, for PE. The results strongly advocate that the suggested facile colorimetric biosensor may provide an excellent platform for on-site monitoring of OPs.

Coal bio-transformation technologies can convert the neglected low rank coal reserves to alternative fuels and non-fuel organic chemicals. Fungal mediated coal degradation can serve as biological beneficiation for alternative substances. For enhanced biodegradation, fungi can be isolated from coal environments and optimized for coal degradation processes. In this study, an indigenous fungal isolate AD-1, identified as Rhizopus oryzae by fungal ITS sequences, was isolated from a low rank coal sample collected from Darra Adam Khel, Frontier Region Kohat, Pakistan. The AD-1 mediated coal degradation was optimized and showed a substantial release of organics at 1.5% glucose and 0.5% coal loading ratio within 11 days. The GC–MS analysis of the black liquid from coal solubilization showed a variety of organic compounds including aromatic acids, fatty acids, alkanes, amines, and amides. The depolymerized liquid extract was analyzed by High-Performance Size-Exclusion Chromatography (HPSEC) for determining the molecular mass distribution of the released organics. The release of the organic fragments had molecular mass distribution ranging between 1.5 kDa and 26.7 kDa. In addition, the released fraction and residual coal sample after solubilization were analyzed with Fourier transform infrared spectroscopy (FT-IR) to explore the structural changes aroused by the AD-1 fungal treatment. The AD-1 fungal strain has the abilities of decarboxylation and deamination, as well as breaking the side chains of the aromatic rings. This demonstrates that indigenous fungi from coal environments can enhance the biodegradation and shows a potential for producing chemical feedstock or alternative fuels from low rank coal.

A mixed culture of A. ferrooxidans and A. thiooxidans isolated from a coal gangue dump was used to bioleach coal gangue in a column reactor to investigate the leaching of elements. The changes of metal ions (Fe, Mn and Cr) and sulfate in the leaching solution, elemental composition, mineral components and sulfur speciation of the coal gangue before and after bioleaching were analyzed by atomic absorption, anion chromatography, XRF, XRD and XPS. The results show that the mixed culture could promote the release of metal ions in coal gangue, with a leaching concentration of Fe &gt, Mn &gt, Cr. EC and Eh have significantly increased with the increase of metal ion concentrations in the leaching solution. XRF analyses show that the contents of Fe, Mn and S decreased in coal gangue after bioleaching. XRD results suggest that the bioleaching has impacts on minerals in coal gangue, particularly the Fe-containing components. XPS analyses show that sulfur speciation in the raw gangue samples was associated with sulfate, dibenzothiophene and pyrite sulfur. After continuous leaching by the mixed culture, the total sulfur, pyrite sulfur and sulfate sulfur in coal gangue decreased from 2.06% to 1.18%, 0.66% to 0.14% and 1.02% to 0.52%. The desulfurization rates of the pyrite and sulfate were 78.79% and 49.02 %. It is concluded that the mixed culture of these two microorganisms could effectively leach metals from coal gangue coupling with the oxidation of sulfide to sulfate. This study has provided fundamental information as a potential application in the recovery of valuable metals from coal gangue or environmental remediation related to gangue in the future.

Biogenic coalbed methane (CBM) is generally believed to be formed by anaerobic bacteria and methanogens, while a few studies took fungi into account. Here, the microflora consisting of fungi and methanogens was enriched from the produced water associated with the Qinshui Basin using anthracite as the only carbon source. The maximum methane yield of 231 μmol/g coal was obtained after 22 days of cultivation under the optimum temperature of 35 °C, pH of 8, salinity of 0–2%, particle size of 0.075–0.150 mm, and the solid–liquid ratio of 1:30. It could remain active even after exposure to air for 24 h. Miseq results showed that the archaea were mainly composed of Methanocella, a hydrogenotrophic methanogen, followed by acetoclastic methanogen Methanosaeta and Methanosarcina, which could use various methanogenic substrates. The fungal communities mainly included Amorphotheca, Alternaria, Aspergillus, and Penicilium, which are all able to degrade complex organics such as aromatics and lignin. After cultivation, the crystal structure of anthracite became looser, as shown by XRD results, which might be due to the swelling effect caused by the destruction of the aromatic ring structure of coal under the function of fungi. The stretching vibration intensity of each functional group in coal decreased with cultivation, as revealed by FTIR. The GC-MS results showed that the concentration of alkanes and alcohols decreased significantly, which are the products of ring-opening of aromatics by fungi. These results suggested that fungi and methanogens in the coalbed also can syntrophically degrade coal effectively, especially for aromatics in coal.

Currently, conversion of coal into alternative fuel and non-fuel valuable products is in demand and growing interest. In the present study, humic acid was extracted from two different ranks of coal, i.e., low rank and high rank (lignite and bituminous), through chemical pretreatment by nitric acid. Samples of lignite and bituminous coal were subjected to nitric acid oxidation followed by extraction using KOH and NaOH gravimetric techniques. The chemical pretreatment of both types of coal led to enhanced yields of humic acid from 21.15% to 57.8% for lignite low-rank coal and 11.6% to 49.6% bituminous high rank coal. The derived humic acid from native coal and nitric acid treated coal was analyzed using elemental analysis, E4/E6 ratio of absorbance at 465 nm and 665 nm using UV-Visible spectrophotometry and Fourier transformed infrared spectroscopy FTIR. The chemical characteristics of coal treated with nitric acid have shown increased molecular weight and improved aromaticity with more oxygen and nitrogen and lower C, H, and sulphur content. The E4/E6 ratio of nitric acid-treated low and high ranks of coal was high. The FTIR spectroscopic data of nitric acid-treated lignite coal indicates an intensive peak of carboxyl group at 2981.84 cm−1, while bituminous coal was shown in cooperation with the N-H group at 2923.04 cm−1. SEM was performed to detect the morphological changes that happen after producing humic acid from HNO3 treatment and native coal. The humic acid produced from HNO3 treated coal had shown clear morphological changes and some deformations on the surface. SEM-EDS detected the major elements, such as nitrogen, in treated humic acid that were absent in raw coal humic acid. Hence, the produced humic acid through HNO3 oxidation showed a more significant number of humic materials with improved efficiency as compared to native coal. This obtained humic acid can be made bioactive for agriculture purposes, i.e., for soil enrichment and improvement in growth conditions of plants and development of green energy solutions.

This study investigates the potential of crude oil degrading capabilities of biosurfactant-producing strains of Pseudomonas aeruginosa MF069166 and Meyerozyma sp. MF138126. P. aeruginosa produced mono-/di-rhamnolipids congeners whereas, Meyerozyma sp. produced acidic and lactonic forms of sophorolipids with crude oil. The values of critical micelle concentrations of rhamnolipids and sophorolipids were 40 mg/L and 50 mg/L with reductions in surface tension of water to 29 mN/m and 33 mN/m. Dynamic light scattering revealed that the average diameter of micellar aggregates of rhamnolipids ranged between 300 and 350 nm and the average size of sophorolipids micelles was 309 nm and 380 nm. Biosurfactants from P. aeruginosa and Meyerozyma sp. exhibited emulsification activities of 87% and 84% in crude oil. Cell surface hydrophobicity of both strains was higher in the presence of hydrophobic contaminants. The biosurfactants showed stability under varying pH, NaCl concentrations and temperatures. Gravimetric and GC-MS analyses demonstrated that P. aeruginosa degraded 91% of the petroleum hydrocarbons while Meyerozyma sp. showed 87% biodegradation efficiency. P. aeruginosa and Meyerozyma sp. have also been found to degrade halogen-containing compounds and showed excellent crude oil degradation efficiency. It is concluded that both strains have high potential of applications in the bioremediation of hydrocarbons-contaminated sites.

Co-degradation of coal and straw could produce significantly higher methane which was potential to increase biogenic CBM. In this study, the success of microflora and organic compounds during co-degradation was determined by MiSeq and GC-MS, and compared with cultivations with only coal (C) and with only straw (RS). The results showed that the methane production in co-degradation was 12 times higher than that in cultivation C. A shift of dominant methanogen was caused by the addition of straw from acetoclastic Methanosaeta in inoculum to methylotrophic Methanomethylovorans in 7 days, then hydrogenotrophic Methanobacterium. The bacteria and fungi with ability to degrade macromolecules in coal and metabolize VFAs were enriched which would facilitate methanogenesis. VFAs, especially butanoic acid, were dominant in intermediates of co-degradation which contributed to methane production as their content were negatively corelated with methane production. The different component of intermediates and microbial communities among co-degradation, cultivations C and RS suggested that the metabolic pathway in co-degradation was distinctive and the fracture of coal molecules was almost completed in the first 7 days of cultivation. Coal might also serve as the suitable microhabitat for microorganisms to avoid the threat from environment in addition to function as methanogenic substrates.

Skin darkening results as a consequence of the accumulation of skin pigment melanin. To combat this, the amplitude of skin lightening agents are commercially available, most of which inhibit melanin synthesis. Decolorization of melanin is an alternative method of skin lightening. In this study, we show that lignin peroxidase (LiP), an extracellular enzyme purified from Phanerochaete chrysosporium NK-1 isolated from a forest soil can effectively degrade and decolorize melanin in vitro. Decolorization conditions including pH, temperature, incubation time, enzyme concentration, and mediator addition were investigated to optimize the reaction conditions. The results indicate that pH 3, 40 °C, 15 IU/ml, and 10 h incubation were the optimal conditions for the decolorization of the melanin. The use of the mediator, veratryl alcohol was also found effective to enhance the efficacy of the melanin decolonization, with up to 92% decolorization. The scanning electron microscopy results showed void spaces on the treated melanin granules as compared to the untreated sample, indicating the degradation of melanin. Changes in the fingerprint region of the melanin were observed. Between wavenumbers 1500–500 cm−1, for example, the presence of new peaks in the treated melanin at 1513, 1464, and 1139 cm−1 CH2, CH3 bend and C–O–C stretch represented structural changes. A new peak at 2144 cm−1 (alkynyl C≡C stretch) was also detected in the decolorized melanin. The cytotoxicity study has shown that the treated melanin and LiP have low cytotoxic effects; however, the mediator of veratryl alcohol could result in high mortality which suggests that its use should be meticulously tested in formulating health and skincare products. The findings of the study suggest that LiP produced by Phanerochaete chrysosporium has the potential to be used in the medical and cosmetic industries, particularly for the development of biobased cosmetic whitening agents.

Coalbed methane (CBM) has great environmental and economic values in addition to its energy content. For years natural gas has been considered a transitional cleaner energy source as it emits less carbon dioxide and other pollutants than other fossil fuels. Due to thebiogenic origin of CBM in many reservoirs, microbial enhancement may also be used to stimulate gas production in coal seams; however, the CBM output is relatively low when compared to other sources of natural gas. Studies have shown that chemical pretreatment of coal prior to gas production can significantly increase the bioconversion rate of coal. This review summarizes and discusses the mechanisms of coal biotransformation and biodegradation in the context of CBM production using chemical pretreatment methods, as well as the latest development in the field, in order to promote the further development of CBM resources.

Argemone ochroleuca oil methyl esters (Biodiesel) optimization was carried out using statistical analysis by one-way ANOVA, determining the R2; finally, the results are evaluated by F-test. Reaction temperature and time were most influencing factors, and experimental model appears to be fit. One-step biodiesel synthesis was followed, using alkali (NaOH) catalyzed reaction. The maximum yield of biodiesel (91%) was obtained at 65°C, at reaction time 120 min, and 7:1 methanol to oil ratio.

International audience; Background: Alkaline proteases is the important group of enzymes having numerous industrial applications including dairy food formulations.Objectives: The current study deals with the purification and characterization of an alkaline serine protease produced by Geotrichum candidum QAUGC01, isolated from indigenous fermented milk product, Dahi.Material and Methods: In total twelve G. candidum strains were screened for their proteolytic activity by using standard protease assay. The protease production from G. candidum QAUGC01 was optimized by varying physio-chemical conditions. The protease was purified by using two-step method: ammonium sulfate precipitation and gel filtration chromatography. Protease was further characterized by studying various parameter like temperature, pH, modulators, metal ions and organic solvent. A thermodynamic study was also carried out to explore the half-life of protease.Results: The G. candidum grew profusely at 25 °C and at an initial pH of 4.0 for 72 h of incubation producing 26.21 U/mlmaximum extracellular protease. Protease revealed that Vmax and Km was 26.25 U.ml-1.min-1 and 0.05 mg.mL-1, respectively using casein as substrate. The enzyme was stable at a temperature range (25-45 ºC) and pH (8-9). Residual enzyme activity was strongly inhibited in the presence of PMSF (7.5%). The protease could hydrolyze proteinaceous substrates, casein (98%) and BSA (95%). The thermodynamic studies explored that the half-life of the enzyme that was 106.62 min, 38.72 min and 15.71 min at 50, 60 and 70 ºC, respectively.Conclusions: Purified protease from G. candidum GCQAU01 is an ideal candidate for industrial application.

Plastics are polymeric materials, and their disposal is a great problem in today’s society. Large quantities of single-use plastics are used every minute throughout the world. Peroxidase enzymes play a significant role in the biodegradation of polymeric materials due to oxidoreductase capability. The objective is to determine which set of conditions optimize the production of peroxidase enzymes by Phanerochaete chrysosporium so as to degrade polymeric materials. The sequential order of parameters in terms of their relevant performance in the bioprocess was determined as urea > polyvinyl chloride > incubation time > polyethylene > veratryl alcohol > sucrose > ammonium sulfate > glucose > ferrous sulfate and polystyrene. Statistical analysis was performed by using analysis of variance which indicated the significance of model Plackett–Burman and components on the basis of F value and P value of 0.012678

Biological routes of synthesising metal nanoparticles (NPs) using microbes have been gaining much attention due to their low toxicity and eco‐friendly nature. Pseudomonas aeruginosa JP2 isolated from metal contaminated soil was evaluated towards extracellular synthesis of silver NPs (AgNPs). Cell‐free extract (24 h) of the bacterial isolate was reacted with AgNO(3) for 24 h in order to fabricate AgNPs. Preliminary observations were recorded in terms of colour change of the reaction mixture from yellow to greyish black. UV‐visible spectroscopy of the reaction mixture has shown a progressive increase in optical densities that correspond to peaks near 430 nm, depicting reduction of ionic silver (Ag(+)) to atomic silver (Ag(0)) thereby synthesising NPs. X‐ray diffraction spectra exhibited the 2θ values to be 38.4577° confirming the crystalline and spherical nature of NPs [9.6 − 26.7 (Ave. = 17.2 nm)]. Transmission electron microscopy finally confirmed the size of the particles varying from 5 to 60 nm. Moreover, rhamnolipids and proteins were identified as stabilising molecules for the AgNPs through Fourier transform‐infrared spectroscopy. Characterisation of bacterial crude and purified protein fractions confirmed the involvement of nitrate reductase (molecular weight 66 kDa and specific activity = 3.8 U/mg) in the Synthesis of AgNPs.

Microbial solubilization of coal has been considered as a promising technology to convert raw coal into valuable products. In the present study, initially a total of 50 different aerobic bacterial and fungal isolates have been isolated from soil, coal and water samples of Dulmial Coal Mines, Chakwal, Pakistan, but on the basis of solubilization potential, only four isolates were selected for further study. The intensity of biosolubilization was measured by determining the weight loss of the coal pieces, which was observed to be about 25.93% by Pseudomonas sp. AY2, 36.36% by Bacillus sp. AY3 and 50% by Trichoderma sp. AY6, while Phanerochaete sp. AY5 showed maximum coal solubilization potential i.e. 66.67% in 30 days. UV/Vis spectrum revealed an increase in the pattern of absorbance of all treated samples compared to control referring to solubilization. Fourier transform infrared spectroscopy indicated alterations in the structure of treated coal in comparison to control coal suggesting breakdown i...

The rapid depletion of fossil fuel resources and climatic changes has triggered the researchers' attention to find an alternative and renewable energy source. Thus, biodiesel has been recognized as a potential alternative to petrodiesel for its biodegradability, non-toxicity, and environment-friendly attributes. In this study, an efficient and recyclable Cu–Ni doped ZrO2 catalyst was synthesized and used to produce biodiesel from a novel non-edible caper (Capparis spinosa L.) seed oil. The synthesized catalyst was characterized by x-ray diffraction, fourier-transform infrared spectroscopy, scanning electron microscopy, and energy dispersive x-ray analysis. The catalyst was reused in four consecutive transesterification reactions without losing any significant catalytic efficiency. Transesterification reaction conditions were optimized via response surface methodology based on Box-Behnken design for predicting optimum biodiesel yields by drawing 3D surface plots. Maximum biodiesel yield of 90.2% was obtained under optimal operating conditions of 1:6 M ratio of oil to methanol, reaction temperature of 70 °C, reaction time of 1.5 h, and 2.5% catalyst loading. Fourier-transform infrared spectroscopy, gas chromatography–mass spectrometry, and nuclear magnetic resonance (1H and 13C) analysis confirmed the high quality of biodiesel produced from non-edible caper (Capparis spinosa L.) seed oil. The fuel properties of the produced biodiesel were also found, such as kinematic viscosity (4.17 cS T), density (0.8312 kg/L), flash point (72 °C), acid no (0.21 mgKOH/g) and sulphur content (0.00042 wt%). These properties were matched and are in close agreement with the International Biodiesel Standards of European Union (EU-14214), China GB/T 20,828 (2007), and American (ASTM6751). Thus, non-edible Capparis spinosa L. seed oil and Cu–Ni doped ZrO2 catalyst appeared to be highly active, stable, and cheap candidates to boost the future biodiesel industry.

Super-critical CO2 enhanced coalbed methane (Sc-CO2-ECBM) and microbially enhanced coalbed methane (MECBM) are environment-friendly technologies that can improve CBM recovery and generation. In this study, a new approach of MECBM based on Sc-CO2 extraction is presented. The Sc-CO2 pretreatment experiments of anthracite and bituminous coal were conducted to produce biomethane. The extracted organics and the changes of coal structure caused by Sc-CO2 were also analyzed to discuss the mechanism of methane stimulation. The results indicated that methane yields have been greatly improved after Sc-CO2 extraction by 734.85% and 148.15% for anthracite and bituminous coal, respectively. The extractions observed by GC-MS analysis is also favored to generate methane by microorganisms. The little increment of methane production from coal treated by subcritical CO2 indicated that the special characteristics of Sc-CO2 were critical for the stimulation of methane production. More functional groups and even new functional groups were formed to increase coal bioavailability after Sc-CO2 extraction. The specific surface area and total pore volume of bituminous coal increase after Sc-CO2 extraction that could provide more action sites for microorganisms and enzymes. These results strongly proved the feasibility of enhancing CBM by microbial degradation based on Sc-CO2 extraction.

The development of bio-processing low rank coal into fuels and non-fuel products has received growing interest in recent years, e.g., production of alternative chemical stock (i.e., humic acids) by the fungal transformation. Previous studies have demonstrated that fungal strains isolated from coal environments can play an important role in the coal-transformation processes with in vivo optimization and chemical pretreatments. In this study, the influence of chemical pretreatments (nitric acid and hydrogen peroxide) with a fungal isolate from coal on the depolymerization of Pakistani subbituminous coal was conducted. The chemical pretreatment exhibited enhanced production of humic acid from 13.5% to 54.2% for nitric acid and 45.7% for hydrogen peroxide. Nitric acid was more effective pretreatment in individual and combination with fungal-mediated depolymerization than hydrogen peroxide. The production of fungal-transformed liquid-derived humic acids were 36.4% and 31.1% for nitric acid and hydrogen peroxide pretreated coal. The results showed that the fungal-transformed humic acid has a high molecular weight, elevated aromatic condensation with mono and poly-substituted functional groups than the chemically treated and raw coal-derived humic acids. The fungal treatment also increased the nitrogen content in the resultant extract, which can be beneficial to the functionality of humic acids. By combining chemical and fungal treatment, it is possible to improve the quantity and quality of humic acids extracted from low rank coal. This is a promising approach in the development of more sustainable-cleaner products from Pakistan’s coal resources for the production of bio-active humic acid.

The present study investigated the possibility of microbial transformations of coal to gas (biogasification) as an alternative to conventional coal mining because this approach has the potential to be less expensive, cleaner, and provide greater access to deeper coal resources. Biogasification is often associated with low rank coal such as lignite and subbituminous coal that has produced enough coalbed methane to be commercially viable in the United States and Australia. However, little work has been done to analyze the potential of biogasification in higher rank coal. For this purpose, bioassay using a wetland-derived consortium and a coal-derived consortium were used to analyze coal samples from Pakistan belonging to different ranks (lignite to semi-anthracite). Among all samples a low volatile bituminous coal produced the maximum methane 34.95 μmol CH4/g coal with the wetland-derived microbial consortium, followed by subbituminous coal (30.18 μmol CH4/g coal). Lower methane levels were recorded with the coal-derived consortium, with subbituminous coal yielding the highest concentration (25.1 μmol CH4/g coal). Methane levels appeared to be increasing on the last measurement indicating the coal-derived consortium was slower than the wetland-derived consortium but could still catalyze biogasification in higher rank coals. Quantitative polymerase chain reaction analysis for mcrA functional genes indicated that the microbial community members that produce methane (methanogens) varied during the incubations. Energy conversion efficiency of different strategies (other biological and underground coal gasification processes) was also compared and discussed. This study was the first to compare bioassay using consortia of microbes non-indigenous and indigenous to coal and indicate the potential of biogasification from many different coalbeds across Pakistan.

Fungal metabolites are playing an immense role in developing various sustainable waste treatment processes. The present study aimed at production and characterization of fungal lignin peroxidase (EC 1.11.1.14) with a potential to degrade Polyvinyl Chloride. Optimization studies revealed that the maximum enzyme production occurred at a temperature 25°C, pH 5 in the 4th week of the incubation period with fungal strain. Enzyme assay was performed to find out the dominating enzyme in the culture broth. The molecular weight of the enzyme was found to be 46 kDa. Partially purified lignin peroxidase from Phanerocheate chrysosporium was used for the degradation of PVC films. A significant reduction in the weight of PVC film was observed (31%) in shake flask experiment. FTIR spectra of the enzyme-treated plastic film revealed structural changes in the chemical composition, indicating a specific peak at 2943 cm−1 that corresponded to alkenyl C–H stretch. Moreover, deterioration on the surface of PVC films w...

Biofilms contain a diverse range of microorganisms and their varying extracellular polysaccharides. The present study has revealed biofilm succession associated with degradative effects on plastic (polypropylene) and contaminants in sludge. The wet weight of biofilm significantly (p 80%) and in chemical parameters (decrease in COD, BOD5 of 73.32 and 69.94%) representing diminution of organic pollutants. Energy dispersive X-ray spectroscopy (EDS) of plastic revealed carbon and oxygen contents, further surface analysis of plastic by scanning electron microscopy (SEM) revealed emergence of profound bacterial growth on the surface. Fourier transform infrared (FTIR) spectroscopy conforms its biotransformation under aerobic conditions after 8 weeks. New peaks developed at the region 1050 and 969 cm(-1) indicating CO and CC bond formation. Thus plastic with 6 weeks old aerobic biofilm (free of pathogens, max. weight, and OD, efficient COD & BOD removal ability) is suggested to be maintained in fixed biofilm reactors for wastewater treatment.

The present study evaluated the effectiveness and durability of TDR for biofilm development and related long term usage in fixed biofilm reactors for wastewater treatment. TDR incubated (30±2oC) with activated sludge showed comparatively higher biofilm development (0.51g) under aerobic than under anaerobic (0. 42g) conditions after 7 weeks. During biofilm succession, a significant shift in bacterial community was observed from pathogenic to autotrophic after 4 weeks. The decreasing bacterial count (MPN index) ( 80%) (E .coli and feacal coliforms) and COD, and BOD (70% approx.) depicted diminishing organic load in sludge. While, changes in pH and nutrients like NO2-, NO3-, PO43-and SO32- indicated presence of other key-bacterial species with efficient nutrient consuming abilities in biofilm. Scanning Electron Microscopy showed few aberration and rich bacterial growth on treated TDR. Furthermore, detailed analysis through FTIR spectroscopy confirmed minor transformation in TDR under anaerobic conditions. TDR proved to be considerably durable and cost effective support material that can be used in aerobic fixed biofilm reactors for wastewater treatment. However, operational conditions of the reactor should be optimized to keep the biofilm structure intact and for achieving desired wastewater treatment efficiency.

The recalcitrant nature of polyvinyl chloride creates serious environmental concerns during manufacturing and waste disposal. The present study was aimed to isolate and screen different soil fungi having potential to biodegrade PVC films. After 10 months of soil burial experiment, it was observed that a number of fungal strains were flourishing on PVC films. On morphological as well as on 18rRNA gene sequence and phylogenetic basis they were identified as Phanerochaete chrysosporium PV1, Lentinus tigrinus PV2, Aspergillus niger PV3, and Aspergillus sydowii PV4. The biodegradation ability of these fungal isolates was further checked in shake flask experiments by taking thin films of PVC (C source) in mineral salt medium. A significant change in color and surface deterioration of PVC films was confirmed through visual observation and Scanning electron microscopy. During shake flask experiments, P. chrysosporium PV1 produced maximum biomass of about 2.57 mg ml(-1) followed by A. niger PV3. P. chrysosporium PV1 showed significant reduction (178,292 Da(-1)) in Molecular weight of the PVC film than control (200,000 Da(-1)) by gel permeation chromatography. Furthermore more Fourier transform infrared spectroscopy and nuclear magnetic resonance also revealed structural changes in the PVC. It was concluded that isolated fungal strains have significant potential for biodegradation of PVC plastics.

The detoxification of xenobiotic organic compounds by various microorganisms through oxidative coupling is facilitated with oxidoreductases. With the help of energy yielding biochemical reactions, these microbes extract energy for their metabolic pathway. They promote the transfer of electrons from a reduced organic substrate to another chemical compound. During such oxidation-reduction reactions, the toxic polymeric substance is finally oxidized into harmless compounds. Enzymatic bioremediation of toxic organic pollutant is a very effective strategy in complex environmental conditions. Oxidoreductases enzymes have a significant potential for the bioremediation of the xenobiotic compounds. Various electron donor complex polymeric substrates containing Phenol and aromatic amines are oxidized by peroxidase in the presence of H2O2 while O2 in the case of dioxygenase. This review attempts to present relevant information on the peroxidases and dioxygenase from various microbial isolates involved in the biodegradation of a wide range of pollutants.

Polystyrene is considered stable to biological degradation. Lantinus tigrinus isolated from wood sample produced esterase in growth medium under normal conditions. However, acidic medium, 37 degrees C temperature, presence of tween 80; and urea and yeast extract in mineral salt medium enhance the production of esterase and specific activity. Purified esterase was active at broad pH range and 45 degrees C. FTIR analysis confirmed that esterase produced by Lantinus tigrinus effectively degraded polystyrene film and broke macromolecules down to non-toxic molecules. This study concludes that the presence of Lantinus tigrinus at dumping sites can be exploited for waste management containing high molecular weight synthetic polymers.

Syed Zeeshan Haider Naqvi, Urooj Kiran, Muhammad Ishtiaq Ali, Asif Jamal, Abdul Hameed, Safia Ahmed, Naeem Ali Microbiology Research Laboratory, Department of Microbiology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan Abstract: Biological synthesis of nanoparticles is a growing innovative approach that is relatively cheaper and more environmentally friendly than current physicochemical processes. Among various microorganisms, fungi have been found to be comparatively more efficient in the synthesis of nanomaterials. In this research work, extracellular mycosynthesis of silver nanoparticles (AgNPs) was probed by reacting the precursor salt of silver nitrate (AgNO3) with culture filtrate of Aspergillus flavus. Initially, the mycosynthesis was regularly monitored by ultraviolet-visible spectroscopy, which showed AgNP peaks of around 400–470 nm. X-ray diffraction spectra revealed peaks of different intensities with respect to angle of diffractions (2θ) corresponding to varying configurations of AgNPs. Transmission electron micrographs further confirmed the formation of AgNPs in size ranging from 5–30 nm. Combined and individual antibacterial activities of the five conventional antibiotics and AgNPs were investigated against eight different multidrug-resistant bacterial species using the Kirby–Bauer disk-diffusion method. The decreasing order of antibacterial activity (zone of inhibition in mm) of antibiotics, AgNPs, and their conjugates against bacterial group (average) was; ciprofloxacin + AgNPs (23) > imipenem + AgNPs (21) > gentamycin + AgNPs (19) > vancomycin + AgNPs (16) > AgNPs (15) > imipenem (14) > trimethoprim + AgNPs (14) > ciprofloxacin (13) > gentamycin (11) > vancomycin (4) > trimethoprim (0). Overall, the synergistic effect of antibiotics and nanoparticles resulted in a 0.2–7.0 (average, 2.8) fold-area increase in antibacterial activity, which clearly revealed that nanoparticles can be effectively used in combination with antibiotics in order to improve their efficacy against various pathogenic microbes. Keywords: mycosynthesis, silver nanoparticles, antibacterial agents, Aspergillus flavus