Isolation of functional ligninolytic Bacillus aryabhattai from paper mill sludge and its lignin degradation potential.

Kraft lignin (KL), is the major pollutant in pulp and paper effluent and due to its heterogeneous structure, it is resistant to the depolymerization process. It has drawn much attention from the researcher due to its challenging degradation process. In this study, a KL-degrading bacterium was isolated and screened from paper mill sludge. This bacterium was identified as ligninolytic Bacillus aryabhattai using biochemical and 16SrRNA gene analysis. B. aryabhattai showed maximum activities of lignin peroxidase-LiP (0.74 IU mL-1) and manganese peroxidase-MnP (9.2 IU mL-1) on the 4th day, and 5th day, respectively. A total 84% of KL (500 mg L -1) reduction was observed after 14 days. The KL bio-degradation was confirmed based on changes in chemical stracture of KL and new metabolites identification using FTIR and GC-MS, respectively. The study concluded that B. aryabhattai maybe becomes a potential biological agent in KL biodegradation and treatment of other lignin-containing industrial effluents.

Biofilm formation and extracellular polymeric substance (EPS) production by Bacillus haynesii and influence of hexavalent chromium.

Biofilm-forming bacteria play a key role in the removal of heavy metals including hexavalent chromium [Cr(VI)] from contaminated sites. In this study, biofilm-forming B. haynesii was examined for extracellular polymeric substances (EPS) production and hexavalent chromium [Cr(VI)] reduction potential. Exposure of B. haynesii with Cr(VI) (12.5-100 mg L-1) for 48 h enhanced pellicle dry weight (20-24%), cell-size (5.1-23.2%) and cell granularity (8.5-19.2%). Also, EPS production was increased by 10-35% by promoting the synthesis of protein (94-119%) and polysaccharide (2-33%) components in EPS. Further, the reduction (27.7 %) and distribution (15.87%) of Cr(VI) were mainly mediated by EPS than the other cellular fractions. Findings of the study suggest that the EPS from B. haynesii was efficiently reduced to Cr(VI) present in aqueous medium and the potential of the organism can be further explored for the mitigation of Cr(VI) contamination.

Detection and identification of hazardous organic pollutants from distillery wastewater by GC-MS analysis and its phytotoxicity and genotoxicity evaluation by using Allium cepa and Cicer arietinum L.

Distillery industry generates a huge amount of wastewater, which contains a high strength of organic and inorganic load. Accordingly, this study aims to analyze the physico-chemical pollution parameters and the occurrence of phytotoxic, cytotoxic and genotoxic pollutants in wastewater. The result revealed that values of wastewater parameters were recorded as 13268 mg l-1 (BOD), 25144 mg l-1 (COD), 25144 mg l-1 (TS), and 6634 mg l-1 (phosphate), while pH was alkaline. The organic compounds detected by GC-MS were quercetin 7,3',4'-trimethoxy, octadecadienoic acid, propanoic acid, glycocholic acid methyl ester, cantaxanthin, etc. The Allium cepa was used for the toxicity test with different concentrations of wastewater showed a significant level of reduction in root growth and length after exposure and the maximum reduction was at 25% and 20%. Phytotoxicity studies were performed using Cicer arietinum L. with different concentrations of wastewater, which showed adverse effects on seed germination, root length, and the effect was associated with the increasing concentration of wastewater. A. cepa root tips were used for the analysis of mitotic index (MI), nuclear abnormalities (NA), and chromosomal aberrations (CA). MI was decreasing significantly from 72% (control) to 33%, 22%, 23%, 21%, and 18% at 5%, 10%, 15%, 20%, and 25% wastewater concentration, respectively. The A. cepa root tip cells showed chromosomal aberrations and nuclear abnormalities like vagrant, stickiness, chromosomal loss, c-mitosis, binucleated, micronuclei, and aberrant cell. This study concluded that the wastewater treatment process is insufficient and the discharged waste needs a proper assessment to know the associated health risk.

Effective bioremediation of pulp and paper mill wastewater using Bacillus cereus as a possible kraft lignin-degrading bacterium.

The effective degradation of KL from paper mill effluent is an important for environmental safety. This research is primarily concerned with the identification of KL-degrading Bacillus cereus from activated sludge and their possible use for the degradation of Kraft lignin (KL). This strain was involved in the production of lignin peroxidase-LiP (3.20 U/mL), manganese peroxidase-MnP (20.36 U/mL), and laccase (21.35 U/mL) enzymes, which were responsible for high KL degradation (89%) and decolorization (40%) at 1000 mg/L KL in 3 days. The SEM-EDS, UV-Vis, FTIR, and GC-MS analysis were used to analyze the bacterial cell and KL interactions to trace the KL degradation process. The significant reduction of pollutants (KL-72.5%, color-62.0%, COD-45.05%) and reduction in toxicity (80%) of bacterial-treated effluent indicated that B. cereus has the potential to be used in the degradation of pollutants from paper mill effluents.

Effect of sewage sludge biochar on the soil nutrient, microbial abundance, and plant biomass: A sustainable approach towards mitigation of solid waste.

Soils functions, fertility, and microbial abundance may alter in various ways by the biochar amendments to the soil. This study revealed the way of pyrolysis temperature influences the biochar quality and its addition for improving soil properties. The SS biochar was synthesized via pyrolysis and characterized by SEM and FTIR for studying surface images and chemical functional groups. The biochar upon addition with soil was studied for physiological parameters of plants like seed germination index, root length, shoot length, biomass, metal (loid) analysis of soil, SS and SS biochar, total organic content, C: N ratio, NPK values, etc. Besides, combinations of biochar: soil {1:3 (25% + 75%), 1:1 (50% + 50%), and 3:1 (75% + 25%)} ratios were used for studying the effect of biochar on soil microbial community. The 16S rRNA metagenomic analysis revealed the dominance of phyla: Proteobacteria, Actinobacteria, and Acidobacteria that influence the soil nutrient cycle when applied at ratio 1:3. This study highlights the valorization of SS into biochar and studied the effect of biochar augmentation with soil; its impact on soil nutrients, microbial abundance, and plant biomass enhancement. The greener approach also mitigates and helps in the sustainable management of solid wastes, thus reducing GHGs emissions and improves nutrient cycling.

Biochar and environmental sustainability: Emerging trends and techno-economic perspectives.

Environmental pollutants including emerging contaminants are a growing concern worldwide. Organic wastes, such as food waste, compost, animal manure, crop residues, and sludge are generally used as feedstock. The conventional treatment methodologies (primary and secondary treatment process) do not mitigate or remove pollutants effectively. Hence, an effective, low-cost, and environmentally friendly tertiary treatment process is an urgent need. Biochar finds interesting applications in environmental processes like pollutant remediation, greenhouse gas mitigation, and wastewater treatment. Studies have shown that different types of adsorbents (biochars) like, native and engineered biochar are being used in the removal or mitigation of heavy metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, pesticides, disinfectants, polychlorinated dibenzofurans, and dibenzo-p-dioxins from contaminated sites for environmental management. The review discusses ample studieswhich can offer solutions for environmental sustenance and managementand the emerging trends and techno-economic prospectives of biochar for sustainable environmental management.

Current trends and possibilities for exploitation of Grape pomace as a potential source for value addition.

Grape pomace (GP) is a low-value by-product that contains a significant amount of high value-added products. The huge amount of non-edible residues of GP wastes (seeds, skins, leaves and, stems) produced by wine industries causes' environmental pollution, management issues as well as economic loss. Studies over the past 15-20 years revealed that GP could serve as a potential source for valuable bioactive compounds like antioxidants, bioactive, nutraceuticals, single-cell protein, and volatile organic compounds with an increasing scientific interest in their beneficial effects on human and animal health. However, the selection of appropriate techniques for the extraction of these compounds without compromising the stability of the extracted products is still a challenging task for the researcher. Based on the current scenario, the review mainly summarizes the novel applications of winery wastes in many sectors such as agriculture, pharmaceuticals, cosmetics, livestock fields, and also the bio-energy recovery system. We also summarize the existing information/knowledge on several green technologies for the recovery of value-added by-products. For the promotion of many emerging technologies, the entrepreneur should be aware of the opportunities/techniques for the development of high-quality value-added products. Thus, this review presents systematic information on value-added by-products that are used for societal benefits concerning the potential for human health and a sustainable environment.

Dissemination of antibiotic resistance genes, mobile genetic elements, and efflux genes in anthropogenically impacted riverine environments.

Anthropogenically impacted surface waters are an important reservoir for multidrug-resistant bacteria and antibiotic-resistant genes. The present study aimed at MDR, ESBL, AmpC, efflux genes, and heavy metals resistance genes (HMRGs) in bacterial isolates from four Indian rivers belonging to different geo-climatic zones, by estimating the mode of resistance transmission exhibited by the resistant isolates. A total 71.27% isolates exhibited MDR trait, showing maximum resistance towards ß-lactams (P = 66.49%; AMX = 59.04%), lincosamides (CD = 65.96%), glycopeptides (VAN = 25.19%; TEI = 56.91%), cephalosporins (CF = 53.72%; CXM = 30.32%) sulphonamide (COT = 43.62%; TRIM = 12.77%), followed by macrolide and tetracycline. The dfrA1 and dfrB genes were detected in total 37.5% isolates whereas; dfrA1 genes were detected in 33.34%. The sul1 gene was detected in 9.76% and sul2 gene was detected in 2.44% isolates. A total of 69.40% MDR integron positive isolates were detected with intI1and intI2 detected at 89.25% and 1.07%, respectively; encoding class 1 and class 2 integron-integrase. ESBL production was confirmed in 73.13% isolates that harboured the genes blaTEM (96.84%), blaSHV (27.37%), blaOXA (13.68%) and blaCTXM (18.95%) while the frequency of HMRGs; 52.24% (zntB), 33.58% (chrA), and 6.72% (cadD). Efflux activity was confirmed in 96.26% isolates that harbored the genes acrA (93.02%), tolC (88.37%), and acrB (86.04%). AmpC (plasmid-mediated) was detected in 20.9% of the riverine isolates. Detection of such hidden molecular modes of antibiotic resistance in the rivers is alarming that requires urgent and stringent measures to control the resistance threats.

Prevalence and hazardous impact of pharmaceutical and personal care products and antibiotics in environment: A review on emerging contaminants.

Antibiotic resistance is a global health emergency linked to unrestrained use of pharmaceutical and personal care products (PPCPs) as prophylactic agent and therapeutic purposes across various industries. Occurrence of pharmaceuticals are identified in ground water, surface water, soils, and wastewater treatment plants (WWTPs) in ng/L to µg/L concentration range. The prevalence of organic compounds including antimicrobial agents, hormones, antibiotics, preservatives, disinfectants, synthetic musks etc. in environment have posed serious health concerns. The aim of this review is to elucidate the major sources accountable for emergence of antibiotic resistance. For this purpose, variety of introductory sources and fate of PPCPs in aquatic environment including human and veterinary wastes, aquaculture and agriculture related wastes, and other anthropogenic activities have been discussed. Furthermore, genetic and enzymatic factors responsible for transfer and appearance of antibiotic resistance genes are presented. Ecotoxicity of PPCPs has been studied in environment in order to present risk imposed to human and ecological health. As per published literature reports, the removal of antibiotics and related traces being difficult, couples the possibility of emergence of antibiotic resistance and hence sustainability in global water resources. Therefore, research on environmental behavior and control strategies should be conducted along with assessing their chronic toxicity to identify potential human and ecological risks.

Occurrence of emerging sulfonamide resistance (sul1 and sul2) associated with mobile integrons-integrase (intI1 and intI2) in riverine systems.

Global use of antibiotics has exceedingly enhanced in agricultural, veterinary and prophylactic human use in recent days. Hence, these antibiotics can easily be found in the environment. This study revealed the occurrence of emerging MDR and ESBL producing strains, pollution profile, and factors integrons (intI1 and intI2) and environmental factors associated, in the riverine systems under different ecological and geo-climatic zones were investigated. The samples were collected based on anthropogenic intervention such as discharge of domestic wastes, industrial wastes, hospital, and municipal wastes. Among 160bacterial morphotypes, 121 (75.62%) exhibited MDR trait with maximum resistance towards lincosamide (CD = 71.3%), beta-lactams (P = 70.6%; AMX = 66.3%), cephalosporin (CZ = 60.6%; CXM = 34.4%), sulfonamide (COT = 50.6%; TR = 43.8%) followed by macrolide (E = 29.4%), tetracycline (TET = 18.8%), aminoglycosides (S = 18.8%; GEN = 6.3%), fluoroquinolones (NX = 18.1%; OF = 4.4%) and carbapenem (IPM = 5.0%). IntI1 gene was detected in 73 (60.3%) of isolates, whereas intI2 was found in 11 (9.09%) isolates. Eight (6.61%) isolates carried both integron genes (intI1 and intI2). sul1 and dfrA1 genes were detected in 53 (72.6%) and 63 (86.3%) isolates, respectively. A total of 103 (85.1%) were found ESBL positive with the presence of ESBL genes in 100 (97.08%) isolates. In riverine systems most prevalent ESBL gene blaTEM (93.0%) was detected alone as well as in combination with bla genes. The data can be utilized for public awareness and regulation of guidelines by local governing bodies as an alarming threat to look-out against the prevalent resistance in environment thereby assisting in risk management during epidemics. This study is a comprehensive investigation of emerging antibiotic pollutants and its resistance in bacteria associated with factors integrons-integrase responsible for its dissemination. It may also assist in global surveillance of antibiotic resistance and policies to curtail unnecessary antibiotic use.

Bacterial degradation of distillery wastewater pollutants and their metabolites characterization and its toxicity evaluation by using Caenorhabditis elegans as terrestrial test models.

Distillery wastewater has significant amount of coloring compounds and organic substances even after the secondary treatment process, which poses many severe environmental and health threats. However, the recalcitrant coloured compounds have not yet been clearly identified. In this study, two bacterial strains DS3 and DS5 capable to decolorize distillery wastewater (DWW) pollutants were isolated and characterized as Staphylococcus saprophyticus (MF182113) and Alcaligenaceae sp. (MF182114), respectively. Results showed that mixed bacterial culture was found more effective decolorizing 71.83% DWW compared to axenic culture DS3 and DS5 resulting only 47.94% and 50.67% decolorization, respectively. The FT-IR and LC-MS/MS analysis of untreated DWW showed the presence of many recalcitrant compounds having different functional groups, but after bacterial treatment, most of compounds get diminished and the toxicity of DWW was reduced significantly. Further, the Nile red staining of Caenorhabditis elegans exposed to untreated and bacteria treated DWW for evaluation of toxicity assay and results revealed that the worms exposed to untreated DWW showed sharp reduction in total fat content having more profound effects, suggesting the diminished nAchR signaling as compare to bacterial treated DWW. Hence, this study revealed that inadequate disposal of untreated DWW may cause transfer of toxic substances into the environment and receiving water bodies.

Hydrothermal liquefaction of rice husk and cow dung in Mixed-Bed-Rotating Pyrolyzer and application of biochar for dye removal.

This work studied the hydrothermal liquefaction of rice husk (RH) and cow dung (CD) for the production of biochar from RH and CD and use of that biochar for the removal of dye from textile industry effluent. These biomasses were subjected to fast pyrolysis (500 °C), which yielded biochar (22.8 and 29.8%) and bio-oil (60.4 and 57.3%) from RH and CD, respectively. Biochar was characterized based on spectroscopy Fourier Transform Infrared Spectroscopy (FTIR) and morphological studies like Scanning Electron Microscope (SEM) and SEM-EDS. Further, bio-oil samples were characterized by GC-MS into saturated and polyunsaturated fatty acids, carboxylic acids, phenolics and aromatic hydrocarbons. The removal efficiencies of the Congo red dye from prepared biochar in a batch experiment were 66.8-96.9%(RH) and 68.9-98.8%(CD). The adsorption isotherms for Langmuir (R2 = 0.977 and 0.902) and Freundlich (R2 0.842 and 0.883) were calculated for RH and CD biochar, respectively.

Removal of methylene blue dye using rice husk, cow dung and sludge biochar: Characterization, application, and kinetic studies.

The present studies aimed for the removal of Methylene blue (MB) dye using the rice husk biochar (RHB), cow dung biochar (CDB) and domestic sludge biochar (SB) synthesized through slow pyrolysis at 500 °C. The biochar was used for the adsorption of synthetic aqueous MB dye. The removal efficiencies of MB by CDB, RHB and SB in a batch experiment were 97.0-99.0; 71.0-99.0 and 73.0-98.9% at conditions, pH (2.0-11.0); Biochar dosage (0.5-6.0 g/100 mL) for 5 days. Adsorption isotherm of Langmuir constant (KL) were obtained 0.101, 0.583 and 0.128 for RHB, CDB and SB respectively. Further, adsorption kinetics of pseudo first order for RHB, CDB and SB were 0.068, 0.018, and 0.066 while it was 0.031, 0.023 and 0.273 for pseudo second order kinetics. Thus, CDB was more effective adsorbent for the dye removal. The pHz values were 7.8, 6.3 and 6.0 for the CDB, RHB, and SB, respectively.

Stress response of Triticum aestivum L. and Brassica juncea L. against heavy metals growing at distillery and tannery wastewater contaminated site.

This study aimed to investigate the effects of potentially toxic elements on biochemical parameters in wheat (Triticum aestivum L.) and mustard (Brassica juncea L.) plants growing at distillery and tannery wastewater contaminated sites. The analysis of plants showed the highest accumulation of Fe (361 mg kg-1 in wheat root and 359 mg kg-1 in mustard leaves) followed by Zn, Cr and Mn in leaf>shoot>root. Further, the Chl-a, b, and carotenoids content was also found high in plant samples. Results also showed that photosynthetic content in wheat and mustard growing at tannery wastewater contaminated sites was Chl-a 3.92, 4.53 (mg g_1 fw), Chl-b 2.39, 1.29 (mg g_1 fw) and carotenoids 0.28, 0.32 (mg g_1 fw), respectively. Whereas, photosynthetic content in these plants with distillery waste was as Chl-a 3.43, 4.88 (mg g_1 fw), Chl-b 1.12, 2.05 (mg g_1 fw) and carotenoids 0.24, 0.29 (mg g_1 fw), respectively. In addition, the activity of plant enzymes such as SOD, APx, GPX, MDA, H2O2, and CAT was also higher in selected plants in comparison to control plants. Moreover, the high bioconcentration factor of Zn > 1 (1.29) and translocation factor >10 (10.31) of Cr in tannery wastewater affected mustard plants. This study concluded that industrial wastewaters are the primary sources of metal accumulation in agricultural crops and thus, it should not be discharged into the environment before its proper treatment. Hence, the continuous monitoring of sludge/soil, agricultural plants and water quality are imperative for the impediment of possible health hazards to animal and human beings.

Environmental pollution and health hazards from distillery wastewater and treatment approaches to combat the environmental threats: A review.

Distillery industries are the key contributor to the world's economy, but these are also one of the major sources of environmental pollution due to the discharge of a huge volume of dark colored wastewater. This dark colored wastewater contains very high biological oxygen demand, chemical oxygen demand, total solids, sulfate, phosphate, phenolics and various toxic metals. Distillery wastewater also contains a mixture of organic and inorganic pollutants such as melanoidins, di-n-octyl phthalate, di-butyl phthalate, benzenepropanoic acid and 2-hydroxysocaproic acid and toxic metals, which are well reported as genotoxic, carcinogenic, mutagenic and endocrine disrupting in nature. In aquatic resources, it causes serious environmental problems by reducing the penetration power of sunlight, photosynthetic activities and dissolved oxygen content. On other hand, in agricultural land, it causes inhibition of seed germination and depletion of vegetation by reducing the soil alkalinity and manganese availability, if discharged without adequate treatment. Thus, this review article provides a comprehensive knowledge on the distillery wastewater pollutants, various techniques used for their analysis as well as its toxicological effects on environments, human and animal health. In addition, various physico-chemicals, biological as well as emerging treatment methods have been also discussed for the protection of environment, human and animal health.

Influence of bacterial strains on Oryza sativa grown under arsenic tainted soil: Accumulation and detoxification response.

The present study was conducted to study the role of bacterial inoculants in growth, accumulation and tolerance responses in rice grown in arsenic (As) contaminated soil. Results revealed that out of five isolated bacterial strains, strain BBAU/MMM1 (Babasaheb Bhimrao Ambedkar University/Mari Matamandir) exhibited resistant to As(III) to the level of 400 µM As(III) in comparison to other strain which showed toxicity. The isolated strain BBAU/MMM1 1was characterized as gram negative, rod shape, showed positive test nitrate, citrate, catalase and phosphate solubilization with high production of IAA and siderophore. Arsenic treated rice seedlings supplemented with bacterial inoculants BBAU/MMM1 showed increased growth characteristics viz., root length (35.41%), shoot length (32.8%) and fresh weight (30.31%) in comparison to rice treated with As(III) only. In addition, reduced lipid peroxidation and induces cysteine, GSH (reduced glutathione), GSSG (Oxidized glutathione) and antioxidant enzymatic activities were also observed in bacterial supplemented rice seedlings. Further, reduced metal accumulation in root (1351.46-968.67 µg g-1fw), shoot (488.01-378.02 µg g-1fw) and reduced translocation factor (0.583-0.390) in As(III) treated rice seedlings inoculated with bacterial strains clearly reflect protective response of bacterial strain against As toxicity. Thus, isolated bacterial strain could be used as bioremediator as well as growth inducer in paddy field contaminated with arsenic.

Properties of bacterial laccases and their application in bioremediation of industrial wastes.

The bioremediation process of industrial waste can be made more efficient using ligninolytic laccase enzymes, which are obtained from fungi, bacteria, higher plants, insects, and also in lichen. Laccase are catalyzed in the mono-electronic oxidation of a substrate from the expenditure of molecular oxygen. This enzyme belongs to the multicopper oxidases and participates in the cross linking of monomers, involved in the degradation of wide range industrial pollutants. In recent years, these enzymes have gained application in pulp and paper, textile and food industries. There are numerous reviews on laccases; however, a lot of information is still unknown due to their broad range of functions and applications. In this review, the bacterial laccases are focused for the bioremediation of various industrial pollutants. A brief description on structural molecular and physicochemical properties has been made. Moreover, the mechanism by which the reaction is catalyzed, the physical basis of thermostability and enantioselectivity, which requires more attention from researchers, and applications of laccase in various fields of biotechnology are pointed out.