Altitude is the major factor affecting both biodiversity and soil physiochemical properties of soil ecosystems. In order to understand the effect of altitude on soil physiochemical properties and bacterial diversity across the Himalayan cold desert, high altitude Gangotri soil ecosystem was studied and compared with the moderate altitude Kandakhal soil. Soil physiochemical analysis showed that altitude was positively correlated with soil pH, organic matter and total nitrogen content. However soil mineral nutrients and soil phosphorus were negatively correlated to the altitude. RT-PCR based analysis revealed the decreased bacterial and diazotrophic abundance at high altitude. Metagenomic study showed that Proteobacteria, Acidobacteria and Actinobacteria were dominant bacteria phyla at high altitude soil while Bacteroidetes and Fermicutes were found dominant at low altitude. High ratio of Gram-negative to Gram positive bacteria at Gangotri suggests the selective proliferation of Gram negative bacteria at high altitude with decrease in Gram positive bacteria. Moreover, Alphaproteobacteria was found more abundant at high altitude while the opposite was true for Betaproteobacteria. Abundance of Cytophaga, Flavobacterium and Bacteroides (CFB) were also found comparatively high at high altitude. Presence of many taxonomically unclassified sequences in Gangotri soil indicates the presence of novel bacterial diversity at high altitude. Further, isolation of bacteria through indigenously designed diffusion chamber revealed the existence of bacteria which has been documented in unculturable study of WIH (Western Indian Himalaya) but never been cultivated from WIH. Nevertheless, diverse functional free-living psychrotrophic diazotrophs were isolated only from the high altitude Gangotri soil. Molecular characterization revealed them as Arthrobacter humicola, Brevibacillus invocatus, Pseudomonas mandelii and Pseudomonas helmanticensis. Thus, this study documented the bacterial and psychrophilic diazotrophic diversity at high altitude and is an effort for exploration of low temperature bacteria in agricultural productivity with the target for sustainable hill agriculture.

The current energy scenario and policies demand the transition of the fuel economy from conventional fossil fuels to renewable fuels, carbon-neutral fuels, and/or decarbonized fuels. The impact of biomass-derived fuels is well-known as their radiocarbon dating indicates their contribution to young carbon emissions in addition to fewer emissions of particulates, sulfur dioxide, and air pollutants compared to fossil fuels. The various kinds of biomass available in India are already being established as potential sources for the production of biofuels and power generation. In this context, besides the quantity of biomass, environmental and economic factors are critically important for determining the range of conversion processes. Currently in India, agricultural-based biomass is the major partner for bioenergy generation. The annual surplus of agriculture-based biomass from major crops, available after its utilization for domestic use, cattle feeding, compost fertilizer, etc., is about 230 million metric tons (MMT). The estimated gross biomass power potential (based on trends) for 2019–2020 from the selected crops is around 30,319.00 Megawatt electric (MWe) at the pan-India level. However, it can be as high as 50,000 MWe after expanding the scope of available biomass from different energy sources. Moreover, the increasing trend of the country for the production of municipal solid waste (MSW) at a rate of 0.16 million tons (Mt) per day also indicates its potential for bioenergy generation. Nevertheless, its decentralized collection and segregation are key issues to its availability for bioenergy conversion/power generation. Therefore, the need of this hour is an effective utilization strategy plan for every type of available biomass including biomass-based refineries, renewable energy carriers, and/or other value-added products. This review aims to compile the various biomass resources (agricultural residues, municipal solid waste, forest-based biomass, industry-based biomass, and aquatic biomass) available in India and their potential for the generation of bioenergy (CBG, bioethanol, power, co-generation, etc.) through various bioconversion technologies that are available/in progress in the country. It also summarizes the current bioenergy scenario of India and initiatives taken by the Indian Government to achieve its future demand through biomass to energy conversion.

Western Indian Himalaya is very rich in biodiversity. Being a cold climatic region, it possesses various psychrotolerant and psychrophilic microorganisms. Psychrotolerant bacterium Dyadobacter sp. was isolated from this region and studied for its plant growth promoting potential against four legumes and finger millet. This bacterium was able to grow at nitrogen (N) deficient medium at both 10°C and 28°C and gave positive nifH amplification that confirms the psychrotolerant and diazotrophic nature of this bacterium. Pot trial-based study showed that this bacterium was able to promote plant growth by fixing atmospheric nitrogen (N₂) and making it available to plants. Agronomical parameters, leaf nitrate reductase activity, and total chlorophyll content were recorded at 30, 45, 60, and 90 days after sowing and found to be increased over their respective controls. The 16S rDNA and nifH genes were quantified by q-PCR to study the dynamics of total bacterial and diazotrophic abundance due to inoculation of Dyadobacter sp. in soil. Soil chemical properties related to soil fertility were also studied at different time intervals after sowing. We found positive correlation among soil pH, soil nifH gene abundance, soil nitrate concentration, and plant leaf nitrate reductase activity. PCR-DGGE was performed to study persistence of Dyadobacter sp. in soil after inoculation, which showed good persistence of plant growth promoting rhizobacteria (PGPR). Hence, it is concluded that Dyadobacter sp. has potential to promote plant growth by fixing atmospheric N₂ and making it available to plant. Further, psychrotolerant nature of this bacterium can be exploited to enhance plant growth in cold climate agriculture due to its ability to fix atmospheric N₂ at low temperature.