The bio-weathering process contributes majorly in the physical shaping of earth’s surface. The weathering of mineral is coupled to the formation of new minerals and release of bio-available nutrients for flora as well as microbial communities. Granites from the Eastern Dharwar Craton (EDC) India are felsic plutonic igneous rock composed of nutritive minerals. The major elemental composition of granite is such that, it forms an ancient ecological niche for diverse microbial communities. Interdisciplinary approaches were taken to construct a more comprehensive understanding of potential functional attributes of Actinobacteria in bio-weathering of granite. This work includes molecular characterization of the isolated strains, detecting their granite bioweathering potentials through leaching experiments where Nocardioides showed highest mineral leaching indices with iron (Fe) being the most leached element (~ 6372 ppm). Scanning electron microscopic imaging indicated biofilm formation and Actinobacterial hyphae colonization. Petrographic, XRD and FTIR based study shows formation of secondary minerals (kaolinite, vermiculite and smectite). To further establish the hypothesis of soil formation and nutrition transport, long-term (360 days) microcosm was developed. Deterioration and grain size alternations with increase in clay based minerals (kaolinite, vermiculite) and total protein content was observed. A bioinformatics based functional biodiversity approach in link to global bio-weathering of rocks by the genus Actinobacteria was adopted to understand their distribution patterns and contribution to alterations of rock minerals. @en

Arsenic (As) is a naturally occurring metalloid which induces high toxicity to both human and animal health. Although As has some applications in industrial, medicinal and agricultural fields, the increasing concentrations of As in drinking water sources had made it a potential threat to living organisms. Inorganic As is naturally present in groundwater and is adsorbed by plants and crops through the irrigation system. This leads to its accumulation in crops and translocation to humans and animals through food. Increased levels of As can cause various health disorders through acute and chronic exposures such as gastrointestinal, hepatic, respiratory, cardiovascular, integumentary, renal, neurological, and reproductive disorders including stillbirth and infant mortality. Arsenic is also capable of inducing epigenetic changes, thereby causing gene mutations. This chapter focuses on the possible sources of As, leading to environmental contamination and followed by its hazardous effects which pave the way to various human health manifestations.@en

The halophilic bacterial strain WB1 isolated from a hydrothermal vent was taxonomically characterized using multiple proxies, as Halomonas nitroreducens strain WB1. When grown on malt extract/yeast extract (MY) medium, it produced large quantities of exopolysaccharide (EPS). The polymer was synthesized at a higher rate during the log and early stationary phases. The anionic polysaccharide is primarily composed of glucose, mannose, and galactose. The studied EPS was highly viscous and had pseudoplastic nature. The EPS was found to be a mixture of three polysaccharides under FT-IR, which makes it less labile to environmental diagenesis. It also has emulsifying and antioxidant activity along with the binding capacity to heavy metals. The EPS has unique and interesting physical and chemical properties, which are different from earlier reported exo-polysaccharides produced by different bacterial genus. This suggests that the extreme geological niches like hypersaline, hyperthermal, hypothermal, and oligophilic environments, which are not well studied so far, can offer extensive and potential resources for medical, biotechnological and industrial applications. The study clearly showed that the thermal springs from the temperate region can be a potent source of many such industrially important microbial genera and need further detailed studies to be carried out.@en