Cellulolytic Properties of a Potentially Lignocellulose-Degrading Bacillus sp. 8E1A Strain Isolated from Bulk Soil

Abstract

Cellulolytic enzymes produced by spore-forming bacteria seem to be a potential solution to the degradation of lignocellulosic waste. In this study, several dozen bacterial spore-forming strains were isolated from soil and one of them was selected for further studies. The studied bacterial strain was identified to genus Bacillus (strain 8E1A) by 16S rRNA gene sequencing. Bacillus sp. 8E1A showed an activity of carboxymethyl cellulase (CMCase) with visualization with Congo Red-25 mm (size of clear zone). To study CMCase, filter paper hydrolase (FPase), and microcrystalline cellulose Avicel hydrolase (Avicelase) production, three different cellulose sources were used for bacterial strain cultivation: carboxymethyl cellulose (CMC), filter paper (FP), and microcrystalline cellulose Avicel. The highest CMCase (0.617 U mL−1), FPase (0.903 U mL−1), and Avicelase (0.645 U mL−1) production of Bacillus sp. 8E1A was noted for using CMC (after 216 h of incubation), Avicel cellulose (after 144 h of incubation), and CMC (after 144 h of incubation), respectively. Subsequently, the cellulases’ activity was measured at various temperatures and pH values. The optimal temperature for CMCase (0.535 U mL−1) and Avicelase (0.666 U mL−1) activity was 70 °C. However, the highest FPase (0.868 U mL−1) activity was recorded at 60 °C. The highest CMCase and Avicelase activity was recorded at pH 7.0 (0.520 and 0.507 U mL−1, respectively), and the optimum activity of FPase was noted at pH 6.0 (0.895 U mL−1). These results indicate that the cellulases produced by the Bacillus sp. 8E1A may conceivably be used for lignocellulosic waste degradation in industrial conditions.

Bioremediation of Heavy Metals by the Genus Bacillus

“…Mechanisms of direct action include production of various biological substances, for instance, indole-3-acetic acid (IAA), gibberellins, cytokinins, and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, and atmospheric nitrogen fixation (nitrogenase production), or phosphorus solubilization [ 56 , 108 , 109 , 110 , 111 , 112 ]. On the other hand, indirect mechanisms include the production of antibiotics (for example, cyclic lipopeptides), enzymes such as chitinases, cellulases, and glucanases, and siderophore production [ 105 , 113 , 114 , 115 , 116 ].…”

“…Importantly, by conducting research on the PGPB application for bioremediation of heavy metals under controlled conditions, researchers are reducing the number of factors affecting their effectiveness. As is well known, the effectiveness of PGPB is influenced by soil properties (including chemical and microbiological properties), which are modulated by a range of factors including meteorological conditions [ 116 ]. Thereby, there is still a great need for research conducted under field conditions, which will provide a broader view of the interactions between bacteria, plants, and soil, thus leading to an essential step in the transition from laboratory experiments to practical applications.…”

Fermentation Quality and Chemical Composition of Industrial Hemp (Cannabis sativa L.) Silage Inoculated with Bacterial Starter Cultures—A Pilot Study

“…Using a laccase treatment, the authors of [58] decreased the phenolic compound concentration in hemp straw and significantly lowered (p < 0.05) the inhibition levels for biogas production. A new, interesting direction of studies on microbial inoculants for the preservation of green biomass is the selection of microorganisms with specific enzyme activities [59].…”

The Succession of the Cellulolytic Microbial Community from the Soil during Oat Straw Decomposition

“…Soil from different environments can serve as a source of cellulolytic microorganisms. A number of studies focused on the isolation of single strains from various soil types [ 14 , 15 , 16 , 17 , 18 ], but this approach has several flaws. It was reported that cellulolytic bacteria may take up to a fifth of the total soil community [ 19 ].…”