Degradation of multiple PAHs and co-contaminants by microbial consortia and their toxicity assessment.

The anthropogenic activities toward meeting the energy requirements have resulted in an alarming rise in environmental pollution levels. Among pollutants, polycyclic aromatic hydrocarbons (PAHs) are the most predominant due to their persistent and toxic nature. Amidst the several pollutants depuration methods, bioremediation utilizing biodegradation is the most viable alternative. This study investigated the biodegradation efficacy using developed microbial consortium PBR-21 for 2-4 ringed PAHs named naphthalene (NAP), anthracene (ANT), fluorene (FLU), and pyrene (PYR). The removal efficiency was observed up to 100 ± 0.0%, 70.26 ± 4.2%, 64.23 ± 2.3%, and 61.50 ± 2.6%, respectively, for initial concentrations of 400 mg L-1 for NAP, ANT, FLU, and PYR respectively. Degradation followed first-order kinetics with rate constants of 0.39 d-1, 0.10 d-1, 0.08 d-1, and 0.07 d-1 and half-life t 1 / 2  of 1.8 h, 7.2 h, 8.5 h, and 10 h, respectively. The microbial consortia were found to be efficient towards the co-contaminants with 1 mM concentration. Toxicity examination indicated that microbial-treated PAHs resulted in lesser toxicity in aquatic crustaceans (Artemia salina) than untreated PAHs. Also, the study suggests that indigenous microbial consortia PBR-21 has the potential to be used in the bioremediation of PAH-contaminated environment.

Trends in fisheries waste utilization: a valuable resource of nutrients and valorized products for the food industry.

The rise in fisheries production worldwide has caused a remarkable increase in associated anthropogenic waste. This poses significant concerns due to adverse environmental impacts and economic losses. Owing to its renewability, high abundance, and potential as a rich source of many nutrients and bioactive compounds, strategies have been developed to convert fish waste into different value-added products. Conventional and improved methods have been used for the extraction of biomolecules from fish waste. The extracted fish waste-derived value-added products such as enzymes, peptides, fish oil, etc. have been used to fortify different food products. This review aims to provide an overview of the nature and composition of fish waste, strategies for extracting biomolecules from fish waste, and the potential application of fish waste as a source of calcium and other nutrients in food fortification and animal feed has been discussed. In context to fishery waste mitigation, valorization, and circular bioeconomy approach are gaining momentum, aiming to eliminate waste while producing high-quality value-added food and feed products from fishery discards.

Correction: Removal of Petroleum Contaminants Through Bioremediation with Integrated Concepts of Resource Recovery: A Review.

[This corrects the article DOI: 10.1007/s12088-021-00928-4.].

Nano-bioremediation: an eco-friendly and effective step towards petroleum hydrocarbon removal from environment.

Global concern about petroleum hydrocarbon pollution has intensified and gained scientific interest due to its noxious nature, high persistence in environmental matrices, and low degradability. One way to address this is by combining remediation techniques that could overcome the constraints of traditional physio-chemical and biological remediation strategies. The upgraded concept of bioremediation to nano-bioremediation in this direction offers an efficient, economical, and eco-friendly approach to mitigate petroleum contaminants. Here, we review the unique attributes of different types of nanoparticles and their synthesis procedures in remediating various petroleum pollutants. This review also highlights the microbial interaction with different metallic nanoparticles and their consequential alteration in microbial as well as enzymatic activity which expedites the remediating process. Besides, the latter part of the review explores the application of petroleum hydrocarbon degradation and the application of nano supports as immobilizing agents for microbes and enzymes. Further, the challenges and the future prospects of nano-bioremediation have also been discussed.

Proteomic response of Pseudomonas aeruginosa IIPIS-8 during rapid and efficient degradation of naphthalene.

Polycyclic aromatic hydrocarbons (PAHs) are widely distributed in the ecosystem and are of significant concern due to their toxicity and mutagenicity. Bioremediation of PAHs is a popular and benign approach that ameliorates the environment. This study investigated the biodegradation and proteome response of Pseudomonas aeruginosa IIPIS-8 for two-ringed PAH: naphthalene (NAP) to understand proteome alteration during its bioremediation. Rapid biodegradation was observed up to 98 ± 1.26% and 84 ± 1.03%, respectively, for initial concentrations of 100 mg L-1 and 500 mg L-1 of NAP. Degradation followed first-order kinetics with rate constants of 0.12 h-1 and 0.06 h-1 and half-life (t1/2) of 5.7 h and 11.3 h, respectively. Additionally, the occurrence of key ring cleavage and linear chain intermediates, 2,3,4,5,6, -pentamethyl acetophenone, 1-octanol 2-butyl, and hexadecanoic acid supported complete NAP degradation. Proteomics study of IIPIS-8 throws light on the impact of protein expression, in which 415 proteins were quantified in sequential windowed acquisition of all theoretical fragment ion mass spectra (SWATH-MS) analysis, of which 97 were found to be significantly up-regulated and 75 were significantly down-regulated by ≥ 2-fold change (p values ≤ 0.05), during the NAP degradation. The study also listed the up-regulation of several enzymes, including oxido-reductases, hydrolases, and catalases, potentially involved in NAP degradation. Overall, differential protein expression, through proteomics study, demonstrated IIPIS-8's capability to efficiently assimilate NAP in their metabolic pathways even in a high concentration of NAP.

Pyrene remediation by Trametes maxima: an insight into secretome response and degradation pathway.

The rapid pace of economic development has resulted in the release of several polycyclic aromatic hydrocarbons (PAHs) into the environment. Microbial degradation using white-rot fungi is a promising method for the removal of PAHs from the environment. In the present study, biodegradation of recalcitrant PAH by a white-rot fungus, Trametes maxima IIPLC-32, was investigated using pyrene. The pyrene concentration decreased by 79.80%, 65.37%, and 56.37% within 16 days from the initial levels of 10 mg L-1, 25 mg L-1, and 50 mg L-1, respectively. Gas chromatographic-mass spectrometric identification of prominent metabolites 1-hydroxypyrene, 2-methyl-1-naphthyl acetic acid, di-n-butyl phthalate, and diethyl phthalate helped in determining the pyrene degradation pathway. The presence of 81 extracellular proteins was revealed by secretome analysis. The identified proteins up-regulated in response to pyrene degradation were classified into detoxification proteins (6.12%), redox proteins (6.12%), stress proteins (4.08%), metabolic-related proteins (26.53%), translation and transcriptional proteins (49%), catalytic proteins (49%), and other proteins (8.16%). Knowledge of secretome analysis in pyrene degradation helped to understand the degradation mechanism of pyrene. Also, the study suggests that T. maxima IIPLC-32 has the potential to be used in the bioremediation of PAH contaminated aquatic environment.

Biological machinery for polycyclic aromatic hydrocarbons degradation: A review.

Polycyclic aromatic hydrocarbons (PAHs) are hazardous environmental pollutants with widespread and well-recognized health concerns. Amidst more than a hundred known PAHs, 16 are categorized as priority pollutants. Use of widely diverse biological machinery comprising bacteria, fungi, and algae harnessed from contaminated sites has emerged as an ecologically safe and sustainable approach for PAH degradation. The potential of these biological systems has been thoroughly examined to maximize the degradation of specific PAHs by understanding their detailed biochemical pathways, enzymatic system, and gene organization. Recent advancements in microbial genetic engineering and metabolomics using modern analytical tools have facilitated the bioremediation of such xenobiotics. This review explores the role of microbes, their biochemical pathways, genetic regulation of metabolic pathways, and the effect of biosurfactants against the backdrop of PAH substrate structures.

Removal of Petroleum Contaminants Through Bioremediation with Integrated Concepts of Resource Recovery: A Review.

There is an upsurge in industrial production to meet the rising demands of the rapidly growing population globally. The enormous energy demand of the growing economies still depends upon petroleum. It has also resulted in environmental pollution due to the release of petroleum origin pollutants. Soil and aquifers, especially in the direct impact zones of petroleum refineries, are the worst hit. The integrated concept of bioremediation and resource recovery offers a sustainable solution to mitigate environmental pollution. It involves biodegradation, a benign utilization of toxic wastes, and the recycling of natural resources. Bioremediation is considered an integral contributor to the emerging concepts of bio-economy and sustainable development goals. This review article aims to provide an updated overview of bioremediation involving petroleum-based contaminants. Microbial degradation is discussed as a promising strategy for petroleum refinery effluent and sludge treatment. The review also provides an insight into resource reuse and recovery as a holistic approach towards sustainable refinery waste treatment. Furthermore, the integrated technologies that deserve in-depth exploration for future study in the refinery sector are highlighted in the present study.

Application of laccase immobilized rice straw biochar for anthracene degradation.

The present study explores the immobilization of ligninolytic enzyme-laccase on the surface of rice straw biochar and evaluates its application for anthracene biodegradation. The rice straw biochar was acid-treated to generate carboxyl functionality on its surface, followed by detailed morphological and chemical characterization. The surface area of functionalized biochar displayed a two-fold increase compared to the untreated biochar. Laccase was immobilized on functionalized biochar, and an immobilization yield of 66% was obtained. The immobilized enzyme demonstrated operational stability up to six cycles while retaining 40% of the initial activity. Laccase immobilization was further investigated by performing adsorption and kinetic studies, which revealed the highest immobilization concentration of 500 U g-1 at 25 °C. The adsorption followed the Langmuir isotherm model at equilibrium, and the kinetic study confirmed pseudo-second-order kinetics. The equilibrium rate constant (K2) at 25 °C and 4 °C were 3.6 × 10-3 g U-1 min-1 and 4 × 10-3 g U-1 min-1 respectively for 100 U g-1 of enzyme loading. This immobilized system was applied for anthracene degradation in the aqueous batch mode, which resulted in complete degradation of 50 mg L-1 anthracene within 24 h of interaction exposure.