The harnessing of biocatalysts from extreme environment hot spring niche for biomass conversion is significant and promising owing to the special characteristics of extremozymes attributed by intriguing biogeochemistry and extreme conditions of these environments. Hence, in the present study 38 bacterial isolates obtained from hot springs of Manikaran (~ 95 °C), Kalath (~ 50 °C) and Vasist (~ 65 °C) of Himachal Pradesh were screened for glycosyl hydrolases by in situ enrichment technique using lignocellulosic biomass (LCB). Based on their hydrolytic potential 5 isolates were selected and they were Bacillus tequilensis (VCB1, VCB2 and VSDB4), and B. licheniformis (KBFB2 and KBFB3). Cellulolytic activity assayed by growth under submerged fermentation showed that B. tequilensis VCB1 had maximum FPA activity (3.38 IU ml−1) in 48 h, while B. licheniformis KBFB3 excelled for endoglucanase (EGA of 4.81 IU ml−1 in 24 h) and cellobiase (0.71 IU ml−1 in 48 h) activities. Among all the thermophilic biocatalysts evaluated, highest exoglucanase (0.06 IU ml−1) activity was observed in B. tequilensis VSDB4 while endoglucanase of B. licheniformis KBFB3 showed optimum specific activity at pH 7 and 70 °C. Further, the presence of celS, celB and xlnB genes in the isolates suggest their possible role in biomass conversion. Protein profiling by SDS-PAGE analysis revealed that cellulase isoforms migrated with molecular masses of 75 kDa. The endoglucanase activity of promising strain B. licheniformis KBFB3 was enhanced in the presence of Ca2+, mercaptoethanol and sodium hypochlorite whereas moderately inhibited by Cu2+, Zn2+, urea, SDS and H2O2. The results of this study indicate scope for the possible development of novel biocatalysts with multifunctional thermostable glycosyl hydrolases from hot springs for efficient hydrolysis of the complex lignocellulosic biomass into simple sugars and other derived bioproducts leading to biomass valorization.Electronic supplementary materialThe online version of this article (10.1186/s13568-018-0690-4) contains supplementary material, which is available to authorized users.

Long-term research on RNA interference led to an unfathomed understanding of the mechanism of siRNA-mediated silencing and finally siRNA has emerged as a powerful therapeutic tool. With siRNAs virtually every gene in the human genome contributing to a disease becomes amenable to regulation, thus opening unprecedented opportunities for drug discovery. siRNA has a well-established role as a tool for in vitro target screening and validation, besides these recent progresses of siRNA delivery in vivo, this has raised more expectations for siRNA-based drugs as the up-and-coming 'magic bullet'. Although a plethora of articles have been published with siRNA, the fundamentals of siRNA-mediated gene silencing and transforming the functional genomics to novel therapeutics are reviewed in this article with consideration to present hurdles as a new generation challenge.

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