Journal of Bacteriology & Parasitology

Abstract

Genomic Analysis of Tepidimicrobium xylanilyticum: Another Key to Lactate Metabolic Pathway in Thermophilic Anaerobic Digestion

Hou-Chia Tseng*, Minenosuke Matsutani, Naoshi Fujimoto and Akihiro Ohnishi

Tepidimicrobium xylanilyticum is a thermophilic lactate-utilising bacterium that produces H₂, CO₂, and acetate in pure culture using lactate as the sole carbon source. This study aimed to clarify the Thermophilic Lactate Metabolic (TLM) pathway and related genes in T. xylanilyticum participating in lactate metabolism during Thermophilic Anaerobic Digestion (TAD). De novo genome sequencing was used to determine the genomic characteristics of T. xylanilyticum. The annotations and TLM pathways of T. xylanilyticumwere predicted using DFAST and GhostKOALA. Comparative genomic analysis between the isolate EN5CB1 and type strain DSM 23310 of T. xylanilyticum was performed using CD-HIT and CLUSTALW. The genome size of T. xylanilyticum was approximately 2.9-3.1 Mbp with 33.2%-33.3% average GC-content. Through the TLM pathway, T. xylanilyticum was predicted to utilise lactate racemase, L-lactate dehydrogenases and D-lactate dehydrogenases, Pyruvate ferredoxin oxidoreductase, Pyruvate dehydrogenase complex, Phosphotransacetylase, Acetate kinase, and two types of hydrogenases. Comparative genomic analysis demonstrated higher lactate utilisation and H₂ productivity in T. xylanilyticum EN5CB1 due to the insertion of a specific gene cluster and replacement of the ATPase operon. This is the first study to present the genomic characteristics and TLM pathway of T. xylanilyticum, and presents a considerable advance in our understanding of lactate metabolism in TAD.

Published Date: 2024-04-08; Received Date: 2024-03-06