Potential of Bacillus sp. LG7 as a Promising Source of Ligninolytic Enzymes for Industrial and Biotechnological Applications

Abstract

Ligninolytic bacteria are considered a major source of ligninolytic enzymes, which are widely used in a variety of industrial and biotechnological processes. The present study aimed to isolate ligninolytic bacteria with the ability to simultaneously produce laccase, lignin peroxidase (LiP) and manganese peroxidase (MnP) with high enzyme activity. Ligninolytic indicator dyes were used for liquid- and solid-phase assays to screen for ligninolytic bacteria. One bacterial strain with the most outstanding results was chosen for further investigation. This isolate was identified as Bacillus sp. LG7 using 16S rRNA gene sequencing and phylogenetic analysis. Solid-state fermentation was carried out using wheat straw to test the ability of Bacillus sp. LG7 to produce ligninolytic enzymes. The activities of laccase, LiP and MnP were determined using standard enzymatic assays. Bacillus sp. LG7 showed the highest laccase activity on the 6th day of incubation (274.03 ± 2.45 U/L). The highest LiP enzyme activity was also found on the 6th day of incubation (265.48 ± 1.24 U/L). Meanwhile, for MnP, the highest enzyme activity was obtained on the 4th day of incubation (2235.57 ± 2.02 U/L). This study presents Bacillus sp. LG7 as a promising source of ligninolytic enzymes to be used in a variety of industrial and biotechnological processes.