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Phthalic acid esters (PAEs), the pervasive and ubiquitous endocrine‐disrupting chemicals of environmental concern, generated annually on a million‐ton scale, are primarily employed as plasticisers in the production of a variety of plastic products and as additives in a large number of commercial supplies. The increased awareness of various adverse effects on the ecosystem and human health including reproductive and developmental disorders has led to a striking increase in research interest aimed at managing these man‐made oestrogenic chemicals. In these circumstances, microbial metabolism appeared as the major realistic process to neutralise the toxic burdens of PAEs in an ecologically accepted manner. Among a wide variety of microbial species capable of degrading/transforming PAEs reported so far, bacteria‐mediated degradation has been studied most extensively. The main purpose of this review is to provide current knowledge of metabolic imprints of microbial degradation/transformation of PAEs, a co‐contaminant of plastic pollution. In addition, this communication illustrates the recent advancement of the structure–functional aspects of the key metabolic enzyme phthalate hydrolase, their inducible regulation of gene expression and evolutionary relatedness, besides prioritising future research needs to facilitate the development of new insights into the bioremediation of PAE in the environment. [ABSTRACT FROM AUTHOR]

Aims The bacterial communities associated with the gastrointestinal (GI) tract are primarily involved in digestion, physiology, and the immune response against pathogenic bacteria for the overall development and health of the host. Hilsa shad (Tenualosa ilisha), a tropical anadromous fish, found predominantly in Bangladesh and India, has so far been poorly investigated for its gut bacterial communities. In this study, both culture-based and metagenomic approaches were used to detect intestinal isolates of hilsa, captured from both freshwater and seawater to investigate the community structure of intestinal microbiota. Methods and results Culture-dependent approach allowed to isolate a total of 23 distinct bacterial species comprising 16 Gram-negative, and 7 Gram-positive isolates, where Proteobacteria and Firmicutes were identified as the two most dominant phyla. While metagenomic approach explored a wide range of important GI bacteria, primarily dominated by Proteobacteria, Firmicutes, and Bacteroidetes, with Proteobacteria and Firmicutes, being the most abundant in freshwater and seawater samples, respectively. Conclusions A combination of these approaches provided the differential GI-associated bacterial diversity in freshwater and seawater hilsa with the prediction of overall functional potential. Impact Statement The study explored the diversity of gut microbiota in hilsa, one of the most preferred nutritious dietary fish, captured from freshwater and seawater habitats, which may encourage to comprehend the composition of the gut microbiome in relation to the migratory behavior and polyunsaturated fatty acid profile of anadromous fish in general. [ABSTRACT FROM AUTHOR]

COVID-19, which is caused by the novel coronavirus SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2), is the deadliest outbreak of this millennium. Despite adopting several precautionary strategies and guidelines, COVID-19 has spread rapidly, and the number of cases is still in escalation across the world. The various immune-boosting drugs with severe side effects and the vaccines approved after negotiated clinical trials have been struggling to cope with the emergence of new variants of the virus. Nevertheless, given a large number of asymptomatic cases, a high magnitude of recovery rate, and a relatively higher prevalence of morbidity and mortality among immunologically compromised individuals, those affected by an illness, and the elderly, it appears that a healthy microbiome and the associated immune responses are the key factors for survival. Incidentally, the consumption of traditionally popular and nutritious fermented foods, which are composed of biologically functional ingredients and several health-promoting probiotics, offers promising health benefits through the improvement of the immune system in general. Given the progress in functional food research, it has become crucial to understand the impact of a healthy microbiome and the immunomodulatory roles of fermented foods on the battles to combat infectious diseases. Based on the evidence of the impact of probiotics-based fermented foods, the beneficial roles of a few frequently consumed fermented foods in the management of various infections have been resolutely discussed in the present study, with a focus on their antagonistic and immune-modulating effects in the context of the current COVID-19 pandemic. [ABSTRACT FROM AUTHOR]

Degradation of butyl benzyl phthalate (BBP) by a co-culture of Gordonia sp. strain MTCC 4818 and Arthrobacter sp, strain WY was investigated. In the degradation of BBP by the co-culture, the limitations of the individual species in metabolizing BBP were overcome, leading to the development of a consortium capable of complete utilization of this ester. In the degradation of BBP by the co-culture, the presence of multiple esterases was demonstrated in both species by activity staining of non-denaturing gels, indicating their roles in the degradation process. The esterases were found to be inducible, with unique or broad substrate specificities towards BRP and its monoesters. Moreover, a number of catabolic enzymes other than esterases identified in the metabolism of BBP-degraded intermediates facilitated the co-culture-mediated degradation process. The versatility of the co-culture was further established by the rapid and complete degradation of a mixture of phthalate esters of environmental concern.

Staphylococcus sp. strain PN/Y, capable of utilizing phenanthrene as a sole source of carbon and energy, was isolated from petroleum-contaminated soil. In the degradation of phenanthrene by strain PN/Y, various metabolites, isolated and identified by a combination of chromatographic and spectrometric analyses, revealed a novel phenanthrene assimilation pathway involving 2-hydroxy-1-naphthoic acid. Metabolism of phenanthrene was initiated by the dioxygenation on the 1,2-position of phenanthrene followed by meta-cleavage of phenanthrene-1,2-diol, leading to 2-hydroxy-1-naphthoic acid, which was then processed via a novel meta-cleavage pathway, leading to the formation of trans-2,3-dioxo-5-(2'-hydroxyphenyl)-pent-4-enoic acid and subsequently to salicylic acid. In the lower pathway, salicylic acid was transformed to catechol, which was then metabolized by catechol-2,3-dioxygenase to 2-hydroxymuconaldehyde acid, ultimately forming TCA cycle intermediates. The catabolic genes involved in phenanthrene degradation were found to be plasmid-encoded. This detailed study of polycyclic aromatic hydrocarbon (PAH) metabolism by a Gram-positive species involving a unique ring-cleavage dioxygenase in a novel phenanthrene degradation pathway provides a new insight into the microbial degradation of PAHs.

Summary: The alpha/beta‐fold superfamily of hydrolases is rapidly becoming one of the largest groups of structurally related enzymes with diverse catalytic functions. In this superfamily of enzymes, esterase deserves special attention because of their wide distribution in biological systems and importance towards environmental and industrial applications. Among various esterases, phthalate hydrolases are the key alpha/beta enzymes involved in the metabolism of structurally diverse estrogenic phthalic acid esters, ubiquitously distributed synthetic chemicals, used as plasticizer in plastic manufacturing processes. Although they vary both at the sequence and functional levels, these hydrolases use a similar acid–base‐nucleophile catalytic mechanism to catalyse reactions on structurally different substrates. The current review attempts to present insights on phthalate hydrolases, describing their sources, structural diversities, phylogenetic affiliations and catalytically different types or classes of enzymes, categorized as diesterase, monoesterase and diesterase–monoesterase, capable of hydrolysing phthalate diester, phthalate monoester and both respectively. Furthermore, available information on in silico analyses and site‐directed mutagenesis studies revealing structure–function integrity and altered enzyme kinetics have been highlighted along with the possible scenario of their evolution at the molecular level. [ABSTRACT FROM AUTHOR]

Alcanivorax sp. strain MBIC 4326 biodegrades long-chain n-alkylated hydrocarbons by beta-oxidation, forming the intermediate compound cyclohexanecarboxylic acid. This in turn is converted to 1-cyclohexene-1-carboxylic acid and finally to benzoic acid.

A separation method for crude oil components is developed. Alkylbenzothiophenes are found to be susceptible to photooxidation and biodegradaton while alkylbenzenes are found to be susceptible to biodegradation but resist photooxidation. Accompanying charts and graphs provide additional statistical data.

This article presents findings on the transformation of crude oil by photooxidation and biodegradation.

A study was conducted to examine the effects of methyl-substituted aromatic isomers on the metabolic pathways in washed cell suspensions of Sphingomonas paucimobilis strain which was grown on 2,6 dimethylnaphthalene as a carbon and energy source. An isolate taken from a phenanthrene enrichment culture of Sphingomonas paucimobilis was utilized. Results revealed that enzymes with relaxed substrate specificity initiated the metabolism of the methyl group.

Time-of-flight mass spectrometry was used for the first time to analyze the hydrocarbons in crude oil. Alkanes in the saturated fraction of a crude oil sample were chemically ionized by the laser desorption of silver nitrate, and the silver-attached [C.sub.24]-[C.sub.60] alkanes were resolved with mass accuracy below 7 ppm. This technique was used to evaluate the biodegradation of aliphatic hydrocarbons and cycloalkanes by oil-degrading microorganisms resident in seawater. It is shown that the aliphatic hydrocarbons were degraded in the range of 60-80%, while the mono-, di-, tri-, tetra-, and pentacycloalkanes were degraded in the range of 40-55, 20-30, 10-16, 5-9, and [is less than] 5%, respectively. Its high sensitivity and speed of application could result in an analysis by laser desorption silver chemical ionization time-of-flight mass spectrometry being the method of choice for determining high-molecular-weight hydrocarbons in various petroleum products.