Elucidation of microbial diversity and lignocellulolytic enzymes for the degradation of lignocellulosic biomass in the forest soils of Eastern and Western Ghats of Tamil Nadu, India

Abstract

Sustainable sources of energy are sought because of the finite nature of nonrenewable resources. Renewable energy from the lignocellulosic biomass of the forest ecosystem reduces dependency on nonrenewable resources to overcome the global energy crisis. In this study, we evaluated the physicochemical parameters of, and enzymatic activity in, 25 forest soil samples collected from Thandikudi (Western Ghats) and the Sirumalai Hills (Eastern Ghats) in Tamil Nadu, India. Soil‐sample analysis revealed that two samples obtained from the Western Ghats exhibited low and high lignocellulolytic enzyme activity, respectively, and they were considered for further study. Sample A showed low lignocellulolytic enzyme activity, whereas sample B showed high lignocellulolytic enzyme activity. The variation in the soil enzymes led us to determine the microbial communities in these two soil samples using nanopore sequencing, which targeted the V1–V9 regions of 16S rDNA. The results highlighted the positive correlation between physicochemical properties and soil enzymes. Principal component analysis revealed that, among the soil enzymes, saccharase and β‐glucosidase predominantly influenced lignocellulosic biomass degradation. The nanopore sequencing results showed that, among the microbes present, the percentage of Firmicutes was higher in soil sample B (23.03%) compared with soil sample A (14.90%). Among the bacterial genera, Bacillus was abundant in these two soil samples followed by Pseudomonas, Escherichia, and Klebsiella. The variation in the occurrence of enzymes and the availability of nutrients in the two soil samples had a positive effect on the abundance of these microbial genera. Moreover, the plentiful presence of Bacillus in soil sample B indicates the richness of lignocellulose. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd

Elucidating the Rhizosphere Associated Bacteria for Environmental Sustainability

“…Significantly, the degradation mechanism of lignocellulose by aerobic and anaerobic bacterial species differs due to its macromolecular arrangement [58]. Anaerobic bacteria often arrange the cellulase or hemicellulase apparatus into cellulosomes (multi-enzyme complex) composed of enzymes with different activities, including carbohydrate esterases, polysaccharide lysases, and glycoside hydrolases [59].…”

“…However, they do not have functional machinery able to degrade plant cell walls. Alternatively, bacteria naturally synthesizing cellulosomes could be manipulated to increase their capacity to produce ethanol from lignocellulose [58]. Xylanosomes, which are self-organizing protein complexes, were designed and constructed using cellulosomes as template [64].…”

Climate change affects cell‐wall structure and hydrolytic performance of a perennial grass as an energy crop

“…Lignocellulosic materials are mainly composed of cellulose, hemicelluloses, and lignin. 34 Cellulose is a linear homopolysaccharide composed of glucose monomers that can be converted into fermentable sugars through enzymatic hydrolysis, 35 which make feedstocks with higher glucan content likely to be favored in ethanol biorefinery industries from an economic point of view because the cellulose content of the feedstocks is directly proportional to the ethanol yields under optimal processing conditions. 36 Hence, as elevated temperature treatments, eT and eT + eC led to increased glucan content, warming treatment could positively affect ethanol yields (Table 1).…”

Probing cellulolytic yeast from forest ecosystem for the saccharification of Napier fodder biomass

“…Nonrenewable resources may not be sufficient to meet out the energy requirement of the society so there is a swift in the utilization of resources from nonrenewable to renewable for the production of value added compounds (Gaurav et al, 2017;Valliammai et al, 2021). The environment concerning factors which have paved the path for the production of microbial cellulases are global warming and greenhouse effects (Vanhala et al, 2016).…”

“…products by the enzyme cellulase (Lu et al, 2013;Valliammai et al, 2021). Maximum cellulase activity was observed by optimizing the factors like incubation period, temperature, and pH.…”