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COVID-19 (Coronavirus disease of 2019) pandemic is one of the largest health threats the planet has faced in recent decades. Efforts are being continuously made to design a viable drug or a vaccine. Several natural and synthetic molecules are under study for their potency to inhibit viral replication. In order to emphasize the importance of microbial-based natural components in antiviral drug discovery, an attempt has been made through this study to find potential inhibitors for SARS-CoV-2 Papain-Like protease (PLpro) molecule from microbial sources. PLpro, with its multifunctional roles like viral polypeptide proteolysis and suppression of the host's innate immune response, is acting as a potential drug target. The X-ray crystal structure of PLpro and ligand molecules were retrieved from the protein structure database and Npatlas database, respectively. The molecules were screened based on drug likeliness and the pharmacophore model created in reference to a known potent PLpro inhibitor GRL0617. Totally 3272 molecules have undergone the docking process and the complexes of top hits were subjected to 100 ns molecular dynamic simulation. The results showed that Holyrine B, Dihydroarcyriarubin C, Baraphenazine C and 3-hydroxy-3'-N-acetylholyrine A had formed a stable complex in the active site of the PLpro with significant interaction efficiency. Earlier studies showed that Holyrine B could also be a possible inhibitor of the Main protease of SARS-CoV-2, which increases its significance in the process of COVID-19 drug development. In conclusion, these microbial compounds can be considered as possible SARS-CoV-2 inhibitors for further in vitro studies. Communicated by Ramaswamy H. Sarma.

Biosorption is an environment-friendly and economic technique to remediate heavy metals from aqueous systems. In the present study, Artocarpus heterophyllus seed powder was used as a biosorbent material to remove different heavy metals. The batch adsorption studies confirmed the higher removal percentage of the Artocarpus heterophyllus (jackfruit) seed powder for arsenic (As

Dry powder of fruit wastes including pomegranate, grapes, lime, apple, and papaya was used to examine their pigment extraction capability. Solvent combination of hexane and acetone (1:1) produced the maximum extraction for lime waste with a yield of 1.65%. Gas Chromatography and Mass Spectrometry analysis of the crude pigment of lime exhibited the abundance of compounds like chlorogenic acid, caffeic acid, and coumaric acid. Three major bands were obtained in Thin Layer Chromatography. Column Chromatographic purification using ethyl acetate and hexane mixture as eluting phase showed a retention factor of 0.62 for the major band. Nuclear Magnetic Resonance revealed the final structure of the compound as chlorogenic acid. Slight inhibition was exhibited by the compound against Escherichia coli. Adsorption of arsenate by residual fruit waste revealed the highest adsorption in grapes with 92% efficiency. This study enlightens an alternative approach of fruit waste management with the production of value-added products and its utilization of residue as bioadsorbent.

Pigment-producing bacteria were isolated from kitchen wastewaters of the National Institute of Technology, Rourkela. A pink non-virulent bacterial strain PWN1 was selected based on the India Ink Broth and Coomassie Brilliant Blue (R-250) dye assay. According to morphological and biochemical characterization, the strain PWN1was a Gram-negative, rod-shaped, motile, non-coliform bacterium and could utilize only glucose and adonitol as sole carbon source. The pigment was found to be a growth-associated product, and the pigment production was accelerated after 40 h of bacterial culture. Further, 16S rRNA gene-based molecular identification showed its similarity with Enterobacter sp. The pigments were extracted by the solvent extraction method using chloroform and ethanol (3:1). The extracted pigments were then purified through thin-layer chromatography and column chromatography. To maximize pigment production, the culture condition was optimized for maximum biomass production using statistical software Design Expert v13. A quadratic model was structured describing the process efficiently and it suggested a moderate temperature, pH, and a high inoculum concentration which generated biomass of 3.81 ± 0.02 g/L. At optimized condition, 1 L of cell culture produced 3.77 g of biomass which produced a crude pigment of 0.234 g after solvent extraction and 0.131 g after column chromatography, implying a yield of 6.2% for crude pigment and 3.47% for purified pigment from biomass. The yield of the obtained pigment was high enough to draw interest for industrial production, although the application of the pigment is considerable for further study.

A superior arsenite [As (III)] oxidizing strain was isolated by enrichment technique from a shallow aquifer of Bhojpur district, Bihar, India. Along with high As (III) and arsenate [As (V)] resistance [up to 70 mM of As (III) and 1000 mM of As (V), respectively], it showed high resistance to multi-metals and a superior ability to utilize a wide range of carbon sources. The gram-negative rod-shaped strain of Delftia spp. BAs29 was characterized thoroughly for its As (III) oxidation ability. The strain showed mixed growth associated, facultative chemolithotrophic As (III) oxidation process, releasing-67 kJ/reaction of free energy in an exergonic reaction. Testing of cost-effective and natural bio-sorbents showed efficient As (V) removal from the contaminated water. Moringa oleifera showed the maximum As (V) removal capacity of 57.89% among the tested bio-sorbents. This study revealed a two-step approach for arsenic removal with 98.77% efficiency from groundwater using an indigenous As (III) oxidizing strain combined with a natural bio-sorbent.

Arsenic endosmosis causes a severe threat to human health within the developing countries. This study assessed the levels of geogenic arsenic and other heavy metals affecting the release of As in the aquifers within the drinking water sources in Bhojpur district of Bihar, India. Eighteen water samples were collected in triplicates from hand-dug wells in six neighboring villages in proximity to the River Ganga namely Bakhorapur, Gaziapur, Parasrampur (or Kanhachhapara), Saraiya, Paiga and Gundiinin. The physicochemical parameters, ionic content and heavy metal analysis of the collected water samples indicated the region to be highly contaminated with arsenic, zinc, manganese and iron. The arsenic and iron concentration ranged between 24.3 and 168.07 μg/L and 0.17–1.16 mg/L respectively, indicating the excessive withdrawal of groundwater for domestic and irrigation purposes with a significant correlation between both the metals. Elevated concentration of zinc in the region attributed to the excessive application of chemical fertilizers and pesticides. Concentration of manganese was also in the higher range of 0.05–1.15 mg/L, primarily due to the urbanized industrial activities. Human health risk assessment within two population groups in the region indicated that the overall water quality is slightly contaminated but the risk associated with it is low. Water Quality Index ranged from 29 to 48, signifying the water quality to be poor. Residual sodium carbonate values indicated that few water sample sources are not suitable for irrigation purposes whereas, sodium adsorption ratio (SAR) values were within the acceptable limits to be used for irrigation.

Ethanol resistant bacterial strain Enterobacter sp. EtK3 was isolated from kitchen wastewater through enrichment culture. The isolated strain was found to produce ethanol by fermenting dried banana peel without any pre-treatment. Ethanol production was confirmed by High-Performance Liquid Chromatography (HPLC) analysis of the fermentation broth. Sequence analysis of the 16S rRNA gene of bacterial isolate EtK3 confirmed its relation with the Enterobacteriaceae family. The temperature of 35 °C with pH 7 utilizing 15.5 gL-1 fruit waste was found to be most favorable for ethanol production after a two-level, three-factor optimization study using Response Surface Methodology (RSM). In the optimized condition, a 23.6% yield of ethanol was obtained. Kinetic study of cell growth, ethanol production and reducing sugar utilization revealed that ethanol production was growth associated with product inhibition at the late log phase. Proximate analysis of pre and post-fermented fruit waste showed subsequent depletion of the fixed carbon content of waste indicating carbon utilization of EtK3 strain from the waste sample. Waste degradation was further confirmed by Scanning Electron Microscope with Energy Dispersive X-Ray (SEM-EDX) and Fourier Transform Infrared Spectrometer (FTIR). An empirical representation of the waste was derived to produce a complete mass balance of the whole ethanol production process from fruit waste.

Hydrocarbon-degrading bacteria were isolated from 2% hydrocarbon enriched sample collected from vehicular repairing stations, garages and petrol bunk. Incubation of the isolated non-virulent strains in Bushnell-Haas (BH) medium supplemented with hydrocarbon, showed their ability to survive on hydrocarbon thereby reducing the total organic carbon content. Based on the degradation potential, different bacterial consortia were prepared and consortium CHM1 was found to grow best with maximum degradation. 16S rRNA gene sequencing of the strains revealed their identity with Klebsiella spp., Enterobacter sp. and Pantoea sp. high to moderate affinity towards hydrocarbon of the selected strains were indicated by Bacterial Adhesion To Hydrocarbon (BATH) test and Contact Angle. Gas Chromatography-Mass Spectrometric (GC-MS) analysis of the mixed hydrocarbon containing broth revealed the presence of benzene derivatives, aliphatic acids, naphthalene, aliphatic alkanes, cyclic aliphatics as major compounds. The efficiency of the selected bacterial consortium showed an overall 16.20% degradation of the mixed hydrocarbon after 4 days, where, aliphatic cyclic compound (1-(1,5-Dimethylhexyl)-4-(4-Methylpentyl)-Cyclohexane) were completely degraded, naphthalene derivatives were reduced to 36.72%, aliphatic acids were degraded to 78.13% and benzene derivatives to 24.16%. Degradation of the long-chain aliphatic alkanes was further observed through Fourier Transform Infrared spectrometric (FTIR) analysis.

The history of microbial interaction with metals and metalloids is very ancient which intrigued the thrust of environmental microbiologist for their exploitation in achieving a clean environment. The co-existence of the microbes with metals emerged the enlistment of divalent or transition metals in every prospect of microbial growth, metabolism and differentiation. The outcome of inequity to the heavy metals/metalloids in the surroundings and their improvement, is controlled by diverse metal-microbe-interactions including bio-sorption, bioaccumulation, bio-precipitation, biotransformation or bio-mobilization/ chelation. Though small quantities of these metals are essential for normal physiological function but their intake is subject to intrinsic homeostatic mechanisms ensuring sufficient but not excessive acquisition. The emergence of such interactive mechanisms not only facilitates environmental fate of metals by their redox transformation or altered mobility/solubility and toxicity but also ensures the adaptation of microorganisms in a changing environment. These interaction mechanisms that lead to alteration in toxicity and mobility of metals and metalloids, are being studied so that they can be applied for bioremediation of toxic element. Exploring these aspects of microbe metal interaction not only provide valuable insight into the role of inhabiting microbes in metal and metalloids cycling but also offer promising strategies for bioremediation of theses metals from diverse contaminated environments. The interdisciplinary field of bio-geo-chemical-interactions across the microbiota grips much potential for future developments in understanding several molecular mechanisms in basic research as well as their application in emerging field of bioremediation technologies.