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The present investigation reports, the bacterial cellulose (BC) a high-purity polymer produced from isolated strain ZKE7. BC production was optimized by Plackett–Burman and central composite designs yielding 18.5 g/l BC with a 4.5-fold enhancement. BC composites functionalized with antibiotics, BC-gelatin hydrogel, BC-Chitosan hydrogel and BC silver nanoparticle composites were developed and evaluated for water retention capability, moisture content and protein adsorption. The drug release behavior of the composites was consistent for controlled drug delivery. Composites were assessed for functional characteristic such as antimicrobial properties. BC composites functionalized with Neotericine exhibited antifungal activity against Candida albicans. Other composites showed pronounced antibacterial properties against Escherichia coli, Bacillus subtilis and Micrococcus luteus. Structural and thermal characterization of BC composites was carried out by FTIR, SEM with energy dispersive X-ray analysis, TGA and differential scanning calorimetry analysis. The results reveal high BC production with excellent properties that can be employed in biomedical field.

A potential biosurfactant producing isolate was identified as Bacillus aryabhattai strain ZDY2. Biosurfactant production was enhanced by 2.51-fold through the development of an optimized process using response surface methodology. The optimized culture medium contained crude oil 4.0%, yeast extract 0.7% and NaNO3 3.0% that yielded 8.86 g/l of biosurfactant. Biosurfactant was characterized for stability up to 100 °C, at pH 5–10 and in the presence of NaCl concentration up to 8%. Biosurfactant demonstrated antimicrobial activity against Salmonella typhimurium, Escherichia coli, Micrococcus luteus, Staphylococcus aureus and Candida tropicalis. The morphological characterization was carried out by scanning electron microscopy with energy-dispersive X-ray analysis. The Fourier-transform infrared spectroscopy analysis reveals the lipopeptide nature of the biosurfactant produced by B. aryabhattai strain ZDY2. The biosurfactant finds application in healthcare and pharmaceutical industries.

Pharmaceutical active drug(s) especially sulfamethazine (SMZ) is considered as one of the major emerging microcontaminants due its long-term existence in the environmental system and that can influence on the developmental of antibacterial resistance genes. Because of this region it has a great concern in the aquatic system. Moreover, the vast utilization of SMZ, excretion of undigested portion by animals and also through dumping or mishandling, SMZ is frequently detected in various samples (including water) of different places and its surroundings. Additionally, reports shown it has toxic effect against microalgae and mice. Thus, that can lead to several investigators, focusing on removal of SMZ alone or in combination of other drugs in wastewater treatment plants (WWTPs) either by abiotic and/or biotic treatment methods. The present review provides an overview of the toxic effect of SMZ and SMZ degradation/removal in abiotic and biotic processes. Finally, reveals the need of further implication of integrated treatments (including engineered biological mediators) to understand ideal biological approaches for the mineralization of SMZ.

In the present study, 13 endocrine disrupting compounds (EDCs) and their transformation products (TPs) were monitored in Jiulong River and its estuary, China in different seasons. The analytes included antimicrobials [triclosan (TCS) and triclocarbon (TCC)]; estrogens [estrone (E1), estradiol (E2), estriol (E3) and ethinylestradiol (EE2)]; alkylphenol ethoxylates [4-n-nonylphenol (NP) and 4-n-octylphenol (OP)] and the TPs [methyl triclosan (MeTCS), carbanilide (NCC), dichlorocarbanilide, 4-hydroxy estrone (4-OH E1) and 4-hydroxy estradiol (4-OH E2)]. A significant seasonal variation was observed for most EDCs. Approximately, 79% of the total E2 residues were detected in the normal season in comparison with the wet season to indicate recalcitrant behavior of E2 during the normal season. Risk assessment revealed that E2 was most potent among the EDCs to cause highest risk to both vertebrate and invertebrate aquatic species, whereas, E1, EE2, MeTCS and TCS also showed relatively high risk for some surface water aquatic species.

Triclosan (TCS) is a synthetic chlorinated aromatic compound and a typical antibacterial agent widely used in a diverse range of personal care products. Generally, after normal use, TCS is flushed ...

In this study, a green approach by utilizing Acacia nilotica leaves (ANL) extract to produce silver nanoparticles (AgNPs) has been made. The biosynthesized AgNPs displayed surface plasmon resonance (SPR) centered at 430 nm. Fourier transform infrared spectroscopy (FTIR) and energy-dispersive spectra (EDS) results showed the contribution of phyto-constituents of ANL in the reduction, capping and stabilizing matrix for AgNPs. The AgNPs were characterized by X-ray diffraction (XRD), and high resolution transmission electron microscopy (HR-TEM) revealed the synthesized ANL-AgNPs were crystalline and spherical forms having about ∼20 nm average particle size. ANL-AgNPs exhibited significant antineoplastic efficacy towards SKOV3 ovarian cancer cells (LD50; 66.5 µg/mL) thus could be useful to treat the cancer and to trounce limitations of conventional chemotherapy treatment. The synthesized AgNPs unveiled substantial antioxidant activity represented by common enzyme markers 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) (IC50; 48.4 µg/mL) and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) (IC50; 55.2 µg/mL) activity. The ANL-AgNPs displayed substantial anti-bacterial activity against human pathogenic bacterial strains and also studied their minimum inhibitory and minimum bactericidal concentration (MIC and MBC) for individual strain. Additionally, the synthesized ANL-AgNPs exhibited colorimetric detection of hydrogen peroxide (H2O2) with better selectivity which showed its viability in determining reactive oxygen species in biological and environmental samples. Overall, the ANL-AgNPs could be used in multitasking biomedical applications, including anticancer, antioxidant, and antibacterial potential and also in sensing application.

Vanadium (V) is an essential trace metal for living organisms with broad application, and extensive mining activities have caused heavy metal pollution in the mining area. Currently, there is little information available on the microbial ecology of V mining-impacted soil. Here we report the analysis of microbial community and diversity of V-resistant bacteria in the V-titanium (Ti) magnetite (Fe3O4) mining area in Panzhihua, southwestern China, which is one of the biggest V-Ti Fe3O4 production bases in the world. We found that V made the key contribution to the distribution pattern and microbial community of sampling sites. The sequencing analysis showed high diversity in both surface and subsurface soil samples; in total 129 V-resistant strains (84 strains with V5+-resistance and 45 strains V4+-resistance) were isolated from the metal contaminated soil samples. Actinobacteria, Proteobacteria, and Firmicutes were found to be the dominant phyla under both of the cultivation-dependent and cultivation-independent approaches. Arthrobacter, Streptomyces, Rhodococcus, Nocardioides, Paenibacillus, Bacillus, and Burkholderia were the dominant V-resistant genera, and their tolerance to V varied among different strains. Arthrobacter was found to be the most dominant genera among the isolated strains. Eight isolates with better resistance to V also showed resistance to more than nine heavy metals as well as several antibiotics. The phylogenetically diverse metal-resistant strains could be potential resources for bioremediation of metal-contaminated soils.

Sewage and fecal pollution cause antibiotic resistance genes (ARGs) pollution in urban lagoons. Seasonality also affects ARG dynamics. However, knowledge of factors controlling ARG community assembly across seasons is still limited. Here, we revealed the seasonal variation of ARGs and depict the underlying assembly processes and drivers via high-throughput quantitative PCR in an urban lagoon, China. A higher richness and abundance of ARGs were observed in summer and winter compared to spring and fall (Kruskal-Wallis test, P 0.05). Both ARG and prokaryotic communities were mainly governed by stochastic processes, however, these processes drove ARGs and prokaryotes differently across seasons. Stochastic processes played a more dominant role in shaping ARG communities in summer (average stochasticity: 83%) and winter (75%), resulting in a stable antibiotic resistome. However, no such seasonal pattern of stochastic processes was determined for prokaryotes, indicating a decoupling of the assembly process of ARGs and prokaryotes. Moreover, fecal microorganisms (e.g., Bacteroidetes and Faecalibacterium) mediated the stochastic processes of ARG profiles, via enhancement of prokaryotic biomass and mobile genetic element abundances. The tnpA-07 transposase was the key for the horizontal gene transfer. These findings will enhance our understanding of how fecal pollution shapes ARG community assembly in urban lagoons.

Rivers are a significant reservoir of antibiotic resistance genes (ARGs), yet the biogeographic pattern of riverine ARGs and its underlying driving forces remain poorly understood. Here, we used metagenomic approach to investigate the spatio-temporal variation of ARGs in two adjacent sub-watersheds viz. North River (NR) and West River (WR), China. The results demonstrated that Bacitracin (22.8 % of the total ARGs), multidrug (20.7 %), sulfonamide (15.2 %) and tetracycline (10.9 %) were the dominant ARG types. SourceTracker analysis indicated that sewage treatment plants as the main source of ARGs, while animal feces mainly contributed in spreading the ARGs in the upstream of NR. Random forest and network analyses confirmed that NR was under the influence of fecal pollution. PCoA analysis demonstrated that the composition of ARGs changed along with the anthropogenic gradients, while the Raup-Crick null model showed that homogenizing selection mediated by class 1 integron intI1 resulted in stable ARG communities at whole watershed scale. Structural equation models revealed that microbial community, grassland and several non-antibiotic micropollutants may also play certain roles in influencing the distribution of ARGs. Overall, the observed deterministic formation of ARGs in riverine systems calls effective management strategies to mitigate the risks of antibiotic resistance on public health.

This study deals the biodegradation of crystal violet dye by a ligninolytic enzyme producing bacterium isolated from textile wastewater that was characterized and identified as Aeromonas hydrophila based on the 16 S rRNA gene sequence analysis. The degradation of crystal violet dye was studied under different environmental and nutritional conditions, and results showed that the isolated bacterium was effective to decolourize 99% crystal violet dye at pH 7 and temperature 35 °C in presence of sucrose and yeast extract as C and N source, respectively. This bacterium also produced lignin peroxidase and laccase enzyme, which were characterized by the SDS-PAGE analysis and found to have the molecular weight of ~ 40 and ~ 60 kDa, respectively. Further, the GC-MS analysis showed that CV dye was biotransformed into phenol, 2, 6-bis (1,1-dimethylethyl), 2′,6′-dihydroxyacetophenone and benzene by the isolated bacterium and the toxicity of CV dye was reduced upto a significant level as it showed 60%, 56.67% and 46.67% inhibition in seed germination. But, after the bacterial degradation/decolourization, it showed only 43.33%, 36.67% and 16.67% inhibition in seed germination after 24, 48 and 72 h, respectively. Thus, this study concluded that the isolated bacterium has high potential for the degradation/decolourization of CV dye as well to reduce its toxicity upto a significant level.

Sulfamethoxazole (SMX) is a common medicine prescribed to treat infections. Due to vast use, SMX has been detected in different parts of the world. Hence, it has become a high risk because of its long term persistence with high biological activity in the ecosystem. Therefore, it is necessary to understand the mechanism of SMX degradation in different genus of bacteria, which is presently unclear. In the present study, degradation of 5 mg L −1 SMX was studied in three isolated pure bacterial cultures, Ochrobactrum sp. SMX-PM1-SA1, Labrys sp. SMX-W1-SC11 and Gordonia sp. SMX-W2-SCD14 and results showed up to 45.2%, 62.2% and 51.4% degradation, respectively within 288 h. Additionally, strain SA1 and strain SCD14 showed up to 66.2% and 69.2% of 4-aminophenol degradation at an initial concentration of 5 mg L −1 within 216 h whereas Labrys sp. SMX-W1-SC11 completely degraded 4-aminophenol at the same concentration within 120 h. Moreover, all three pure bacteria also completely degraded 3-amino-5-methylisoxazole at initial concentration of 4 mg L −1 within 120 h. Furthermore, gas chromatography-mass spectrometry and quadrupole time-of-flight mass spectrometry analysis results revealed that 3-amino-5-methylisoxazole, 4-aminophenol and hydroquinone were the three main by-products of SMX catabolism. In addition, cell free extracts of both Labrys sp. SMX-W1-SC11 and Gordonia sp. SMX-W2-SCD14 showed hydroquinone dioxygenase activity. Besides, all three bacterial strains showed resistance to different heavy metals. Moreover, all three pure bacterial cultures also showed positive chemotactic response toward 3-amino-5-methylisoxazole and hydroquinone based on the drop plate assay. The results of this study recommend these microorganisms for bioremediation of SMX contaminated sites.

Summary Although the health of rivers is threatened by multiple anthropogenic stressors with increasing frequency, it remains an open question how riverine microbial communities respond to emerging micropollutants. Here, by using 16S rDNA amplicon sequencing of 60 water samples collected during different hydrological seasons, we investigated the spatio-temporal variation and the co-occurrence patterns of microbial communities in the anthropogenically impacted Jiulong River in China. The results indicated that the riverine microbial co-occurrence network had a non-random, modular structure, which was mainly shaped by the taxonomic relatedness of co-occurring species. Fecal indicator bacteria may survive for prolonged periods of time in river water, but they formed an independent module which had fewer interactions with typical freshwater bacteria. Multivariate analysis demonstrated that nutrients and micropollutants (i.e. pharmaceuticals and personal care products, PPCPs) exerted combined effects in shaping α- and β-diversity of riverine microbial communities. Remarkably, we showed that a hitherto unrecognized disruptive effect of PPCPs on the abundance variations of central species and module communities was stronger than the influence of physico-chemical factors, suggesting the key role played by micropollutants for the microbial co-occurrence relationships in lotic ecosystems. Overall, our findings provide novel insights into community assembly in aquatic environments experiencing anthropogenic stresses. This article is protected by copyright. All rights reserved.

Purpose Current research focuses on the biological delignification of biomass by microbial laccase which is an environmentally friendly process. Methods Various statistical approaches were designed for optimization of laccase production like Plackett–Burman design as well as response surface methodology (RSM). A laccase mediator system was designed for the delignification of saw dust which was molecularly characterized by high-performance liquid chromatography (HPLC), Fourier transformation infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Results The present study reveals wheat bran is a potential substrate for the production of laccase (63 U/g and 9.6 mg/g protein) under solid-state fermentation by Trichoderma harzianum strain HZN10. Statistical optimization by RSM using central composite design (CCD) revealed that wheat bran contributed maximally to the overall laccase production followed by yeast extract. Laccase production under optimized conditions yielded 510 U/g with 8.09-fold increase. HPLC peaks representing 4-hydroxy-3-methoxybenzoic (vanillic) acid and 4-hydroxy-3,5-dimethoxybenzoic (syringic) acid showed drastic reduction in laccase-treated saw dust sample indicating the elimination of toxic inhibitors, thereby signifying the detoxification of sample. The laccase-treated saw dust showed 1.6-fold increase in reducing sugars after enzymatic (cellulase) hydrolysis. The FTIR analysis revealed the structural alterations occurring during the delignification process. SEM of biologically treated saw dust revealed the morphological alterations during the delignification process targeting the fiber cell walls rich in lignin. Conclusion The delignification of saw dust was effective by laccase mediator system and was evidenced by HPLC, FTIR and SEM analysis. Hence, laccase can be a powerful tool in biomass to biofuel conversions.

The current study determined, for the first time, the levels of titanium (Ti), strontium (Sr), barium (Ba), vanadium (V), gallium (Ga), tin (Sn), thallium (Tl), and antinomy (Sb), in deposited dust, and human hair collected from general population of different geographical areas of Pakistan. All the samples were prepared by microwave digestion and measured by ICP-MS. The results showed that on deposited dust samples, the detected elements followed the descending trend as: Ti > Sr > Ba > V > Ga > Sn > Tl > Sb similar to the upper continental crust. The deposited dust samples from low elevation areas exhibited highest levels of all studied elements (except antimony which was higher in soil samples from mountainous areas), followed by rive plains, mountainous areas, and highland valleys. In contrast, on human hair samples, the elements followed the descending trend as: Sr > Ba > Ti > Ga > V > Sn > Sb > Tl respectively. Ba, Ga, and V concentrations were higher in soil samples from lower elevation Indus plain, and Sr, Tl, Sb, and Ti were higher in samples from mountainous areas. The bioaccumulation trend of all studied elements was in descending order as follows: Sb, Ga, Sn, Ba, Sr, Ti, V, Tl, respectively. Principal component analysis (PCA) and correlation matrix evidenced both geological influences and anthropogenic activities as potential sources of these studied elements. On the other hand, the risk estimation (HI > 1) concluded that population were at higher health risk (non-carcinogenic) for Ga and Ti. All other studied rare elements were within safe limit for humans from all zones.

The utilization of abundantly available lignocellulosic biomass requires an efficient cellulolytic enzyme system. Evaluation of an efficient microbial system is a crucial part for the development of useful enzyme production in an industrial process. The present study reports the production of cellulolytic enzymes from various lignocellulosic biomasses by Trichoderma harzianum strain HZN11 characterized by 18S rDNA sequencing. The organism revealed a well-balanced cellulolytic complex of enzyme production (endoglucanase 30.32 U g−1, exoglucanase 15.08 U g−1, FPase 5.56 U g−1, cellobiase 17.92 U g−1, β-glucosidase 11.21 U g−1, and xylanase 1740 U g−1) from sweet sorghum bagasse under solid-state fermentation. Statistical optimization by Plackett–Burman design constituting of 12 experimental runs at two levels of seven independent variables revealed the significant effect of four variables, namely, protease peptone, lactose, MgSO4·7H2O, and K2HPO4 on endoglucanase production at 95% confidence level with R 2=97.68%. Response surface methodology using central composite design was employed with 31 experimental runs at 5 levels with 4 significant independent variables. The responses in the form of contour and 3D plots showed significant interaction effects. Significant interactions existed between the variables at p

In this study we report the purification of laccase produced by Trichoderma harzianum strain HZN10 (using wheat bran under solid state fermentation) and its application in decolorization of synthetic dyes. Extracellular laccase was purified to homogeneity by DEAE-Sepharose and Sephadex G-100 chromatography with specific activity of 162.5 U/mg and 25-fold purification. Purified laccase was immobilized in various entrapments like calcium alginate, copper alginate, calcium alginate–chitosan beads and sol–gel matrix. Optimization results revealed that the laccase immobilized in sol–gel was optimally active in wide pH range (4.0–7.0) and thermo-stable (50–70 °C) than free enzyme which was optimum at 50 °C and pH 6.0. Kinetic analysis showed Km of 0.5 mM and 2.0 mM and Vmax of 285 U/mg and 500 U/mg by free laccase and sol–gel immobilized laccase respectively with 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) [ABTS] substrate. Free and immobilized laccase was employed for decolorization of three different synthetic dyes (malachite green, methylene blue and congo red). High performance liquid chromatography (HPLC) analysis results revealed that approximately 100% of malachite green, 90% of methylene blue and 60% of congo red dyes at initial concentration of 200 mg/L were decolorized within 16, 18 and 20 h, respectively by laccase immobilized in sol–gel matrix in the presence of 1-hydroxybenzotriazole (HBT) mediator. During the decolorization all three synthetic dyes showed various peaks on HPLC chromatogram indicating different by-products formation. Finally, phytotoxicity analysis results revealed that the by-products of synthetic dyes (formed during decolorization) showed less toxicity against Phaseolus mungo compared to untreated synthetic dyes.

The pharmaceutical industry of Pakistan is growing with an annual growth rate of 10%. Besides this growth, this industry is not complying with environmental standards, and discharging its effluent into domestic wastewater network. Only limited information is available about the occurrence of pharmaceutical compounds (PCs) in the environmental matrices of Pakistan that has motivated us to aim at the occurrence and ecological risk assessment of 11 PCs of different therapeutic classes in the wastewater of pharmaceutical industry and in its receiving environmental matrices such as sludge, solid waste and soil samples near the pharmaceutical formulation units along Shiekhupura road, Lahore, Pakistan. Target PCs (paracetamol, naproxen, diclofenac, ibuprofen, amlodipine, rosuvastatin, ofloxacin, ciprofloxacin, moxifloxacin, sparfloxacin and gemifloxacin) were quantified using in-house developed HPLC-UV. Ibuprofen (1673µg/L, 6046µg/kg, 1229µg/kg and 610µg/kg), diclofenac (836µg/L, 4968µg/kg, 6632µg/kg and 257µg/kg) and naproxen (464µg/L, 7273µg/kg, 4819µg/kg and 199µg/kg) showed the highest concentrations among 11 target PCs in wastewater, sludge, solid waste and soil samples, respectively. Ecological risk assessment, in terms of risk quotient (RQ), was also carried out based on the maximum measured concentration of PCs in wastewater. The maximum RQ values obtained were with paracetamol (64 against daphnia), naproxen (177 against fish), diclofenac (12,600 against Oncorhynchus mykiss), ibuprofen (167,300 against Oryzias latipes), ofloxacin (81,000 against Pseudomonas putida) and ciprofloxacin (440 against Microcystis aeruginosa). These results show a high level of ecological risk due to the discharge of untreated wastewater from pharmaceutical units. This risk may further lead to food web contamination and drug resistance in pathogens. Thus, further studies are needed to detect the PCs in crops as well as the government should strictly enforce environmental legislation on these pharmaceutical units.

Increasing extreme precipitation events (EPEs) can induce biogeochemical disturbances in the coastal lagoon ecosystems. Very little is known about the response of prokaryotic communities to such influences, which are the key components mediating the biogeochemical cycling in lagoons. Here 16S rRNA gene amplicon sequencing and high-through quantitative PCR (HT-qPCR) were employed to investigate the distribution of prokaryotic communities and fecal indicator genes in the surface waters of Yundang lagoon, Xiamen, China during EPEs, respectively. Prokaryotic communities from rainwaters, influents (IFs) and effluents (EFs) from a nearby wastewater treatment plant were also characterised. The results indicated a significant variation in the composition of lagoon prokaryotic communities compared with rainwaters, IFs and EFs. Multivariate and phylogenetic signal analyses revealed that environmental filtering, mainly controlled by salinity, was the major ecological process responsible for the temporal succession of lagoon prokaryotic communities during EPEs. Moreover, the pollution indicator taxa (based on amplicon sequencing) and fecal indicator genes (based on HT-qPCR) demonstrated that EPEs may induce sewage overflows and fecal pollution (mainly from humans and dogs), resulting in an increase in the relative abundance of pollution indicator taxa and genes in Yundang lagoon. Network analysis illustrated that the number of network edges and keystone species decreased along the sampling times, implying that EPEs-induced disturbances may affect prokaryotic species associations. Taken together, this study provides an enhanced understanding of the responses of lagoon prokaryotic communities to EPEs-induced disturbances.

Environmental contamination due to heavy metals (HMs) is of serious ecotoxicological concern worldwide because of their increasing use at industries. Due to non-biodegradable and persistent nature, HMs cause serious soil/water pollution and severe health hazards in living beings upon exposure. HMs can be genotoxic, carcinogenic, mutagenic, and teratogenic in nature even at low concentration. They may also act as endocrine disruptors and induce developmental as well as neurological disorders, and thus, their removal from our natural environment is crucial for the rehabilitation of contaminated sites. To cope with HM pollution, phytoremediation has emerged as a low-cost and eco-sustainable solution to conventional physicochemical cleanup methods that require high capital investment and labor alter soil properties and disturb soil microflora. Phytoremediation is a green technology wherein plants and associated microbes are used to remediate HM-contaminated sites to safeguard the environment and protect public health. Hence, in view of the above, the present paper aims to examine the feasibility of phytoremediation as a sustainable remediation technology for the management of metal-contaminated sites. Therefore, this paper provides an in-depth review on both the conventional and novel phytoremediation approaches; evaluates their efficacy to remove toxic metals from our natural environment; explores current scientific progresses, field experiences, and sustainability issues; and revises world over trends in phytoremediation research for its wider recognition and public acceptance as a sustainable remediation technology for the management of contaminated sites in the twenty-first century.

Keratin is a global class of biological material, which represents a group of cysteine-rich filament-forming proteins. They serve as a shielding layer for the epidermal appendages like nails, claws, beak, hair, wool, horns, and feathers. These proteins are further subdivided into two different class based on their secondary structure: α-keratin and β-keratin. Keratin is insoluble in hot or cold water; this unique property helps to prevent their digestion by proteolytic enzymes. Additionally, their complex hierarchical-like filament-matrix structure at nanoscale and the polypeptide chains create a robust wall for protection against heat stress, pathogen invasions (particularly through skin), mechanical damage, etc. In this review, we are trying to attempt a linear focus in the direction of structure, function, extraction of keratin, and its industrial applications.

Polyhydroxyalkanoates (PHA) are appealing as an important alternative to replace synthetic plastics owing to its comparable physicochemical properties to that of synthetic plastics, and biodegradable and biocompatible nature. This review gives an inclusive overview of the current research activities dealing with PHA production by utilizing different waste fluxes generated from food, milk and sugar processing industries. Valorization of these waste fluxes makes the process cost effective and practically applicable. Recent advances in the approaches adopted for waste treatment, fermentation strategies, and genetic engineering can give insights to the researchers for future direction of waste to bioplastics production. Lastly, synthesis and application of PHA-nanocomposites, research and development challenges, future perspectives for sustainable and cost-effective PHB production are also discussed. In addition, the review addresses the useful information about the opportunities and confines associated with the sustainable PHA production using different waste streams and their evaluation for commercial implementation within a biorefinery.

Due to the intensive use of pesticides within the greenhouse-rose production, remediation of polluted soils has become a hot topic for researchers in recent decades. Several bacterial strains having the ability to utilize various pesticides as a sole source of carbon and energy were isolated from pesticide-contaminated soils of Urcuqui, Ecuador. According to phenotypical, physiological, and biochemical characterizations, and 16S rRNA gene sequence analysis, the isolated pure bacterial cultures were identified as Pseudomonas putida sp. strain B1, Acinetobacter sp. strain B2 and Arthrobacter sp. strain B3. The bacterial isolates were used individually and mixed cultures were used in the laboratory and field experimentations for the degradation of various pesticides like Ridomil MZ 68 MG, Fitoraz WP 76, Cleaner, Decis 2.5 CE, Score 250 EC, Zero 5 EC, Bravo 720 SC, Meltatox, Mirage 45 CE and Teldor Combi at 50 mgL-1. The bacterial growth was monitored on both liquid culture medium (in laboratory) and field experiments by spectrophotometer method, Neubauer camera and colony-forming units. In addition, the degradation of individual pesticides (50 mgL-1) was determined by ultra-high performance liquid chromatography-tandem mass-spectrometry and UV-VIS spectrophotometer. The results showed that the highest growth rate of microbial consortium was observed during degradation of various pesticides than individual pure bacteria for both experiments. In addition, most pesticides were completely degraded by microbial consortium after 60 days. Key words: Bioremediation, spectrophotometer, bioreactors, pesticides, consortium.

Bacterial degradation plays a vital role in determining the environmental fate of micropollutants like triclocarban. The mechanism of triclocarban degradation by pure bacterium is not yet explored. The purpose of this study was to identify metabolic pathway that might be involved in bacterial degradation of triclocarban. Triclosan-degrading Sphingomonas sp. strain YL-JM2C was first found to degrade up to 35% of triclocarban (4 mg L(-1)) within 5 d. Gas chromatography-mass spectrometry detected 3,4-dichloroaniline, 4-chloroaniline and 4-chlorocatechol as the major metabolites of the triclocarban degradation. Furthermore, total organic carbon results confirmed that the intermediates, 3,4-dichloroaniline (4 mg L(-1)) and 4-chloroaniline (4 mg L(-1)) could be degraded up to 77% and 80% by strain YL-JM2C within 5 d.

This study investigated a one-pot green and sustainable silver nanoparticles (AgNPs) synthesis by utilizing Portulaca oleracea leaves (PNL) aqueous extract as a reducing agent. The physical and chemical characteristics of the produced AgNPs were studied by employing numerous standard analytical techniques. The analytical outcomes suggest that PNL-AgNPs were crystalline in nature, fabricated with PNL phytochemicals, and circular in shape measuring ∼20 nm in size. Biosynthesized PNL-AgNPs exhibited a significant photocatalytic activity for degrading various reactive textile dyes without the need of any reducing agent. Particularly, of the reactive textile dyes, PNL-AgNPs exhibited higher photocatalytic degradation of Reactive Green 19A (RG19A), wherein its deterioration was studied by measuring the reduction in chemical oxygen demand (COD; 84%) and total organic carbon (TOC; 75%) within 60 min of incubation. The effects of various influencing operational factors, such as temperature, pH, light condition, photocatalyst amount, and dye concentrations, on the photocatalytic degradation of RG19A were systematically examined. The catalytic activity of PNL-AgNPs remains stable up to three repeated cycles, which upsurges the real-world applicability of PNL-AgNPs in textile wastewater treatment. PNL-AgNPs showed significant antibacterial activity and synergy with commercial antibiotics against human pathogenic bacteria. The mechanism underlying antibacterial activity was determined based on bacterial cell membrane disruption and cytoplasmic content leakage. PNL-AgNPs potentially constrain the activity of α-glucosidase and α-amylase enzymes, which are marker enzymes of diabetes. The results obtained indicate the potential application of synthesized PNL-AgNPs in environmental and nano-biomedical applications.

Development of an effective pretreatment method is a vital stage to enhance biomass-based biopolymers production. The present study aims on the pretreatment of wheat waste biomass (WS) with alkaline and in combination with ultrasound (US) treatment to enhance enzymatic saccharification of WS into monomeric sugars. Effects of chemical dosage, substrate loading, US power and US pretreatment time on the pretreatment efficiency were systematically investigated. Under optimized conditions; US + NaOH pretreatment attained maximum 70% delignification of WS, with 84.5% hydrolysis yield, 90% glucose yield and 65% xylose yield after enzymatic hydrolysis (30 FPU/g of dry WS) which is substantially higher than the individual pretreatment. Analytical studies (XRD, FTIR, and SEM) revealed that the combined US + NaOH pretreatment can effectively destroyed the ultrastructure of biomass and improved the accessibility to hydrolyzing enzymes. The resulted enzymatic hydrolysates were utilized as a possible biomass feedstock for polyhydroxybutyrate (PHB) production using Ralstonia eutropha. Effects of supplementation of nutrients, stressing agents and initial concentration of US + NaOH pretreated WS hydrolysates (20 to 40 g/L) on PHB production were evaluated. The maximum 74% PHA accumulation, PHB titer of 7.85 g/L and yield of PHB about 0.441 g/g of reducing sugar production was obtained. Analytical characterization and thermal characteristics of extracted biopolymer showed the poperies of standard PHB. The foregoing results suggested the potential of WS as an alternate renewable resource for sustainable biopolymer production and enables WS waste biomass disposal concerns.

The paucity of effective anticancer drugs for successful treatment is a major concern, indicating the strong need for novel therapeutic compounds. In the quest of new molecules, the present study aimed to explore the potential of pyrazolo[3,4-d]pyrimidine derivatives as antiproliferative agents. In vitro anticancer screening of selected compounds was done by the National Cancer Institute's Developmental Therapeutics Programme against a panel of 60 cancer cell lines. The lead compound PP-31d considerably inhibited the growth of cancer cells, such as NCI-H460 (non-small-cell lung cancer), OVCAR-4 (ovarian cancer), 786-0 (renal cancer), A549 (non-small-cell lung cancer), and ACHN (renal cancer), showing strong anticancer potential, among other derivatives. Kinetic studies of PP-31d on NCI-H460 cells revealed a dose-dependent effect with an IC50 of 2 µM. The observed inhibition by PP-31d is attributed to the generation of reactive oxygen species and the subsequent induction of cellular apoptosis, as evidenced by the increase in the hypodiploid (subG1) population, the early apoptotic cell population, and caspase-3/7 activity, the loss of the mitochondrial membrane potential, and the degradation of nuclear DNA. Collectively, our results demonstrated that pyrazolo[3,4-d]pyrimidine derivatives inhibit cancer cell proliferation by inducing apoptosis and, thus, have the potential to be further explored for anticancer properties.

Tannery wastewater (TWW) is of serious environmental concern to pollution control authorities, because it contains highly toxic, recalcitrant organic and inorganic pollutants. The nature and characteristics of recalcitrant organic pollutants (ROPs) are not fully explored to date. Hence, the purpose of this study was to characterize and identify the ROPs present in the treated TWW. Gas chromatography–mass spectrometry data analysis showed the presence of a variety of ROPs in the treated TWW. Results unfolded that benzyl chloride, butyl octyl phthalate, 2,6-dihydroxybenzoic acid 3TMS, dibutyl phthalate, benzyl alcohol, benzyl butyl phthalate, 4-chloro-3-methyl phenol, phthalic acid, 2′6′-dihydroxyacetophenone, diisobutyl phthalate, 4-biphenyltrimethylsiloxane, di-(-2ethy hexyl)phthalate, 1,2-benzenedicarboxylic acid, dibenzyl phthalate, and nonylphenol were present in the treated TWW. Due to endocrine disrupting nature and aquatic toxicity, the U.S. Environmental Protection Agency classified many of these as “priority pollutants” and restricted their use in leather industries. In addition, the physicochemical analysis of the treated TWW also showed very high BOD, COD, and TDS values along with high Cr and Pb content beyond the permissible limits for industrial discharge. Furthermore, phytotoxicity assessment unfolds the inhibitory effects of TWW on the seed germination, seedling growth parameters, and α-amylase activity in Phaseolus aureus L. This indicates that the TWW discharged even after secondary treatment into the environment has very high pollution parameters and may cause a variety of serious health threats in living beings upon exposure. Overall, the results reported in this study will be helpful for the proper treatment and management of TWW to combat the environmental threats.

The limited information about the sludge quality has made its management a top environmental challenge. In the present study, occurrence and the spatiotemporal variations of 52 inorganic elements were investigated in the sludge samples from three wastewater treatment plants (WWTPs) in Xiamen city, China. The results showed, the occurrence of 49 elements with the concentrations in the range of >125–53500 mg kg−1 dry sludge (DS) for commonly used industrial metals, 1.22–14.0 mg kg−1 DS for precious metals, and 1.12–439.0 mg kg−1 DS for rare earth elements. The geo-accumulation studies indicated a moderate to high levels of buildup of some elements in the sewage sludge. Principal components analysis (PCA) indicated strong spatial and weak temporal variations in the concentrations of the elements. Therefore, the sludge disposal operations, based on the element concentrations, geoaccumulation and economic potential are suggested for each WWTP. Sludge from W1 and W2 were found suitable for agricultural usage, while that from W3 showed a higher economic potential for the recovery of precious metals. This study concludes that a comprehensive analysis of the elements in the sewage sludge could provide critical information for the disposal and management of the sludge.

p-Cresol is an environmental pollutant due to its vast use, toxicity and persistence, nevertheless, its degradation in an enzyme is unclear. In this study, we used Pleurotus sp. isolate VLECK02 polyphenol oxidase (PPO) for the determination of p-cresol degradation. On the basis of UV, FT-IR and chromatographic (HPLC and GC–MS) analysis, 4-methylcatechol was identified as the main metabolite of p-cresol catabolism. In addition, batch and semi-continuous degradation of p-cresol (10 and 20 mM) were studied and compared by free and immobilized PPO in different matrices like sodium alginate (SA), sodium alginate–polyvinyl alcohol (SA–PVA) and sodium alginate–polyvinyl alcohol–silver nanoparticles (SA–PVA–AgNPs). The experimental data showed that an enzyme (PPO) immobilized in SA–PVA–AgNPs was completely degraded p-cresol at initial concentrations of 10 and 20 mM within 30 h. These results suggest that the enzyme immobilized in SA–PVA–AgNPs has achieved higher degradation rates at a given time than free PPO and PPO immobilized in SA–PVA and SA. The SA–PVA–AgNPs and SA–PVA immobilized enzyme could be reused for more than 12 and 8 cycles, respectively, without losing any degradation capacity. Moreover, the immobilized PPO showed higher tolerance to various temperatures and pH than free PPO. Hence, immobilized PPO could be useful for the bioremediation of environment contaminated with phenolic compounds like p-cresol. Electronic supplementary material The online version of this article (doi:10.1007/s13205-016-0547-y) contains supplementary material, which is available to authorized users.

The present study reports the production of high-level cellulase-free xylanase from Penicillium citrinum isolate HZN13. The variability in xylanase titers was assessed under both solid-state (SSF) and submerged (SmF) fermentation. SSF was initially optimized with different agro-waste residues, among them sweet sorghum bagasse was found to be the best substrate that favored maximum xylanase production (9643 U/g). Plackett–Burman and response surface methodology employing central composite design were used to optimize the process parameters for the production of xylanase under SSF. A second-order quadratic model and response surface method revealed the optimum conditions for xylanase production (sweet sorghum bagasse 25 g/50 ml; ammonium sulphate 0.36 %; yeast extract 0.6 %; pH 4; temperature 40 °C) yielding 30,144 U/g. Analysis of variance (ANOVA) showed a high correlation coefficient (R 2 = 97.63 %). Glutaraldehyde-activated calcium-alginate-immobilized purified xylanase showed recycling stability (87 %) up to seven cycles. Immobilized purified xylanase showed enhanced thermo-stability in comparison to immobilized crude xylanase. Immobilization kinetics of crude and purified xylanase revealed an increase in K m (12.5 and 11.11 mg/ml) and V max (12,500 and 10,000 U/mg), respectively. Immobilized (crude) enzymatic hydrolysis of sweet sorghum bagasse released 8.1 g/g (48 h) of reducing sugars. Xylose and other oligosaccharides produced during hydrolysis were detected by High-Performance Liquid Chromatography. The biomass was characterized by Scanning Electron Microscopy, Energy Dispersive X-ray and Fourier Transformation Infrared Spectroscopy. However, this is one of the few reports on high-level cellulase-free xylanase from P. citrinum isolate using sweet sorghum bagasse. Electronic supplementary material The online version of this article (doi:10.1007/s13205-016-0484-9) contains supplementary material, which is available to authorized users.

Mercury (Hg) contamination of environment is a major threat to human health in developing countries like Pakistan. Human populations, particularly children, are continuously exposed to Hg contamination via dust particles due to the arid and semi-arid climate. However, a country wide Hg contamination data for dust particles is lacking for Pakistan and hence, human populations potentially at risk is largely unknown. We provide the first baseline data for total mercury (THg) contamination into dust particles and its bioaccumulation trends, using scalp human hair samples as biomarker, at 22 sites across five altitudinal zones of Pakistan. The human health risk of THg exposure via dust particles as well as the proportion of human population that are potentially at risk from Hg contamination were calculated. Our results indicated higher concentration of THg in dust particles and its bioaccumulation in the lower Indus-plain agricultural and industrial areas than the other areas of Pakistan. The highest THg contamination of dust particles (3000ppb) and its bioaccumulation (2480ppb) were observed for the Lahore district, while the highest proportion (>40%) of human population was identified to be potentially at risk from Hg contamination from these areas. In general, children were at higher risk of Hg exposure via dust particles than adults. Regression analysis identified the anthropogenic activities, such as industrial and hospital discharges, as the major source of Hg contamination of dust particles. Our results inform environmental management for Hg control and remediation as well as the disease mitigation on potential hotspots.

Triclosan (TCS) is one of the most widespread emerging contaminants and has adverse impact on aquatic ecosystem, yet little is known about its complete biodegradation mechanism in bacteria. Sphingomonas sp, strain YL-JM2C, isolated from activated sludge of a wastewater treatment plant, was very effective on degrading TCS. Response surface methodology (RSM) was applied to optimize the conditions like temperature and pH. From RSM, the optimal TCS degradation conditions were found to be 30 °C and pH 7.0. Under optimal conditions, strain YL-JM2C completely mineralized TCS (5 mg L−1) within 72 h. Gas chromatography-mass spectrometry analysis revealed that 2,4-dichlorophenol, 2-chlorohydroquinone and hydroquinone are three main by-products of TCS. Furthermore, stable isotope experimental results revealed that the 13C12-TCS was completely mineralized into CO2 and part of heavier carbon (13C) of labeled TCS was utilized by strain YL-JM2C to synthesize fatty acids (PLFAs). Cell surface hydrophobicity (CSH) and degradation test results suggested that the strain could enhance degradation capacity of TCS through increasing CSH. In addition, the bacterium also completely degraded spiked TCS (5 mg L−1) in wastewater collected from the wastewater treatment plant. Hence, these results suggest that the strain has potential to remediate TCS in the environment.

This study is aimed to assess the biodegradation of sulfadiazine (SDZ) and characterization of heavy metal resistance in three pure bacterial cultures and also their chemotactic response towards 2-aminopyrimidine. The bacterial cultures were isolated from pig manure, activated sludge and sediment samples, by enrichment technique on SDZ (6 mg L-1). Based on the 16S rRNA gene sequence analysis, the microorganisms were identified within the genera of Paracoccus, Methylobacterium and Kribbella, which were further designated as SDZ-PM2-BSH30, SDZ-W2-SJ40 and SDZ-3S-SCL47. The three identified pure bacterial strains degraded up to 50.0, 55.2 and 60.0% of SDZ (5 mg L-1), respectively within 290 h. On the basis of quadrupole time-of-flight mass spectrometry and high performance liquid chromatography, 2-aminopyrimidine and 4-hydroxy-2-aminopyrimidine were identified as the main intermediates of SDZ biodegradation. These bacteria were also able to degrade the metabolite, 2-aminopyrimidine, of the SDZ. Furthermore, SDZ-PM2-BSH30, SDZ-W2-SJ40 and SDZ-3S-SCL47 also showed resistance to various heavy metals like copper, cadmium, chromium, cobalt, lead, nickel and zinc. Additionally, all three bacteria exhibited positive chemotaxis towards 2-aminopyrimidine based on the drop plate method and capillary assay. The results of this study advanced our understanding about the microbial degradation of SDZ, which would be useful towards the future SDZ removal in the environment.

An acidophilic-solvent-thermostable endo β-1,4-d-glucanase produced from a potential Trichoderma harzianum strain HZN11 was purified to homogeneity by DEAE-Sepharose and Sephadex G-100 chromatography with 33.12 fold purification with specific activity of 66.25 U/mg and molecular mass of ~55 kDa. The optimum temperature and pH were 60 °C and 5.5 retaining 76 and 85 % of activity after 3 h, respectively. It showed stability between pH 4.5–6.0 and temperature between 50–70 °C indicating thermostability. Endo β-1,4-d-glucanase was activated by Ca2+ and Mg2+ but inhibited by Hg2+, Pb2+ and Cd2+. The effect of thiol reagents, metal chelators, oxidizing agents and surfactants on enzyme activity has been studied. Purified endo β-1,4-d-glucanase exhibited highest specificity towards carboxymethyl cellulose. Kinetic analysis showed the K m, V max and K i (cellobiose inhibitor) of 2.5 mg/mL, 83.75 U/mg and 0.066 M, respectively. The storage stability of purified endo β-1,4-d-glucanase showed a loss of mere 13 % over a period of 60 days. The hydrolysis efficiency of purified endo β-1,4-d-glucanase mixed with cocktail was demonstrated over commercial enzyme. Optimized enzymatic hydrolysis of sweet sorghum and sugarcane bagasse released 5.2 g/g (36 h) and 6.8 g/g (48 h) of reducing sugars, respectively. Separate hydrolysis and fermentation of sweet sorghum bagasse yielded 4.3 g/L bioethanol (16 h) confirmed by gas chromatography–mass spectrometry (GC–MS). Morphological and structural changes were assessed by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy. Elemental analysis was carried out by SEM equipped with energy dispersive X-ray technique. These unique properties prove the potentiality of enzyme for biomass conversion to biofuel and other industrial applications. Electronic supplementary material The online version of this article (doi:10.1007/s13205-016-0421-y) contains supplementary material, which is available to authorized users.