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

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 dc۴f, le۲f, lc۲, and lb۸, the strain le۲f displayed high laccase activity of ۰.۰۵۹ U ml-۱ toward syringaldazine as a typical laccase substrate. The isolates were identified based on biochemical tests and ۱۶S rRNA gene sequencing analyses. Nucleotide BLAST analyses of ۱۶S rRNA gene sequence exhibited that the strains of dc۴f, lb۸, lc۲, and le۲f, had the most similarity (with more than ۹۸% identity) with Enterobacter sp. strain W-۶ ۱۶S (ACCN: MK۵۰۵۳۹۰), Serratia liquefaciens strain N۱۱۲ (ACCN: MK۶۲۹۷۸۴), Brevibacterium sp. strain ۷۷۳ (ACCN: MH۷۷۷۸۹۷) and Staphylococcus sciuri strain KSI ۷۰۸ (ACCN: KC۱۱۳۱۵۰), respectively. Overall, the current study is the first research on alkaliphilic bacterial strains from the gut of leopard moth with laccase activity.