Molecular advances in mycoremediation of polycyclic aromatic hydrocarbons: Exploring fungal bacterial interactions.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous high global concern environmental pollutants and tend to bioaccumulate due to hydrophobic properties. These xenobiotics, having variable concentrations along different matrices, gradually undergo various physical, chemical, and biological transformation processes. Myco-remediation aids accelerated degradation by effectively transforming complex ring structures to oxidized/hydroxylated intermediates, which can further funnel to bacterial degradation pathways. Exploitation of such complementing fungal-bacterial enzymatic activity can overcome certain limitations of incomplete bioremediation process. Furthermore, high-throughput molecular methods can be employed to unveil community structure, taxon abundance, coexisting community interactions, and metabolic pathways under stressed conditions. The present review critically discusses the role of different fungal phyla in PAHs biotransformation and application of fungal-bacterial cocultures for enhanced mineralization. Moreover, recent advances in bioassays for PAH residue detection, monitoring, developing xenobiotics stress-tolerant strains, and application of fungal catabolic enzymes are highlighted. Application of next-generation sequencing methods to reveal complex ecological networks based on microbial community interactions and data analysis bias in performing such studies is further discussed in detail. Conclusively, the review underscores the application of mixed-culture approach by critically highlighting in situ fungal-bacterial community nexus and its role in complete mineralization of PAHs for the management of contaminated sites.

Myco-remediation of Chlorinated Pesticides: Insights Into Fungal Metabolic System.

Synthetic chemicals including organochlorine pesticides pose environment and health hazard due to persistent and bio-accumulation property. Majority of them are recognized as endocrine disruptors. Fungi are ubiquitous in nature and employs efficient enzymatic machinery for the biotransformation and degradation of toxic, recalcitrant pollutants. This review critically discusses the organochlorine biotransformation process mediated by fungi and highlights the role of enzymatic system responsible for biotransformation, especially distribution of dehalogenase homologs among fungal classes. It also explores the potential use of fungal derived biomaterial, mainly chitosan as an adsorbing biomaterial for pesticides and heavy metals removal. Further, prospects of employing fungus to over-come the existing bioremediation limitations are discussed. The study highlights the potential scope of utilizing fungi for initial biotransformation purposes, preceding final biodegradation by bacterial species under environmental conditions. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12088-021-00940-8.

Etiology of childhood diarrhoea among under five children and molecular analysis of antibiotic resistance in isolated enteric bacterial pathogens from a tertiary care hospital, Eastern Odisha, India.

BACKGROUND: Although, India has made steady progress in reducing deaths in children younger than 5 years, the proportional mortality accounted by diarrhoeal diseases still remains high. The present hospital based cross sectional study was carried out to understand the prevalence of various bacterial pathogens associated with the diarrhoea cases in under 5 years age group. METHODS: During, 1st September, 2015 to 30th November 2017, all the childhood diarrhoea cases (≤5 yrs) of SCB Medical College in Odisha, India were included in the study. Stool samples were collected and processed for the isolation of causative bacterial pathogen and the isolated bacterial pathogens were subjected to antibiotic sensitivity testing, molecular analysis of drug resistance. Clinical and demographic data were collected and analyzed. RESULTS: Three hundred twenty patients were enrolled in the study during the study period from whom 82 bacterial isolates were obtained indicating a proportional causality of 25.6% for bacterial diarrhoea among children in this region. Entero toxigenic E.coli (ETEC) accounted for majority of the cases and and more than 50% of the strains were found to be multi-drug resistant (resistant to more than 3 class of antibiotics). More than 50% of the strains were resistant to current choice of treatment like ciprofloxacin, ofloxacin and ceftriaxone and 2.4% being resistant to Imipenem. ESBL production was also observed in some of the strains and one isolate harboured the NDM-1 gene. Fluoroquinolone resistance was found to be linked with multiple mutations in the QRDR region followed by PMQR determinants. CONCLUSION: The current study, to the best of our knowledge is first of its kind which demonstrated the etiology of bacterial diarrhoea in children less than 5 years old and identified diarrheogenic E. coli as the predominant enteropathogen in Odisha. Majority of the isolates being multi-drug resistance calls for a continuous surveillance system in the region which will be helpfulin identifying emerging resistance pattern and for developing suitable intervention stategies.

Bacterial remediation of pesticide polluted soils: Exploring the feasibility of site restoration.

For decades, reclamation of pesticide contaminated sites has been a challenging avenue. Due to increasing agricultural demand, the application of synthetic pesticides could not be controlled in its usage, and it has now adversely impacted the soil, water, and associated ecosystems posing adverse effects on human health. Agricultural soil and pesticide manufacturing sites, in particular, are one of the most contaminated due to direct exposure. Among various strategies for soil reclamation, ecofriendly microbial bioremediation suffers inherent challenges for large scale field application as interaction of microbes with the polluted soil varies greatly under climatic conditions. Methodically, starting from functional or genomic screening, enrichment isolation; functional pathway mapping, production of tensioactive metabolites for increasing the bioavailability and bio-accessibility, employing genetic engineering strategies for modifications in existing catabolic genes to enhance the degradation activity; each step-in degradation study has challenges and prospects which can be addressed for successful application. The present review critically examines the methodical challenges addressing the feasibility for restoring and reclaiming pesticide contaminated sites along with the ecotoxicological risk assessments. Overall, it highlights the need to fine-tune the available processes and employ interdisciplinary approaches to make microbe assisted bioremediation as the method of choice for reclamation of pesticide contaminated sites.