Cellulase- and Xylanase-Producing Bacterial Isolates with the Ability to Saccharify Wheat Straw and Their Potential Use in the Production of Pharmaceuticals and Chemicals from Lignocellulosic Materials

Abstract

The efficient use of lignocellulosic materials for pharmaceutical and chemical production relies on the hydrolysis of their components into their building blocks (e.g. hexoses and pentoses), which can be converted later into chemicals of interest. This study aimed to isolate cellulase- and xylanase-producing bacteria for the bioconversion of lignocellulosic materials into their respective monomeric sugars. Bacterial isolates were screened using CMC- and Xylan–Trypan blue agar, and then cellulase and xylanase activities were evaluated by the 3,5-dinitro-salicylic acid (DNS) method. Furthermore, bacterial ability to saccharify wheat straw was tested. Ten bacterial isolates were found to have the ability to saccharify wheat straw, and to produce cellulase and xylanase enzymes simultaneously. The bacterial isolates were identified at molecular level using 16S rRNA gene sequencing and phylogenetic analysis. Bacterial isolates were identified as Cellulomonas sp. CX4, Cellulomonas sp. CX5, Bacillus sp. CX6, Bacillus sp. CX10, Paenibacillus illinoisensis CX11, Paenibacillus sp. CX14, Bacillus cereus CX15, and Bacillus sp. CX16, Paenibacillus barcinonensis CX17 and Cellulomonas sp. CX20. Among all the isolates, Bacillus sp. CX6 showed the highest ability to produce total reducing sugar (6.03 and 6.16 mg/ml), while the lowest ability to saccharify wheat straw was found with Cellulomonas sp. CX5 (2.01 and 2.12 mg/ml). This study presents cellulase- and xylanase- producing bacterial isolates for their potential to saccharify lignocellulosic materials for possible use in the production of pharmaceuticals and chemicals.