Isolation and identification of lignin-degrading bacteria with laccase activity from the gut of the leopard moth, Zeuzera pyrina (Lepidoptera: Cossidae)

Abstract

Gut bacterial symbionts have an essential role in the nutrition and fitness of xylophagous insects. These bacteria produce several enzymes like cellulase and laccase which are important in industrial applications. In this study, laccase-producing bacteria were isolated and identified from the gut of the wood borer leopard moth. Four novel laccase positive strains were isolated using guaiacol-containing agar plates. Among the strains of dc4f, le2f, lc2, and lb8, the strain le2f displayed high laccase activity of 0.059 U ml-1 toward syringaldazine as a typical laccase substrate. The isolates were identified based on biochemical tests and 16S rRNA gene sequencing analyses. Nucleotide BLAST analyses of 16S rRNA gene sequence exhibited that the strains of dc4f, lb8, lc2, and le2f, had the most similarity (with more than 98% identity) with Enterobacter sp. strain W-6 16S (ACCN: MK505390), Serratia liquefaciens strain N112 (ACCN: MK629784), Brevibacterium sp. strain 773 (ACCN: MH777897) and Staphylococcus sciuri strain KSI 708 (ACCN: KC113150), respectively. Overall, the current study is the first research on alkaliphilic bacterial strains from the gut of leopard moth with laccase activity.

Keywords

• biological degradation
• lignocellulose
• insect symbionts
• delignification