Whole Genome Sequencing of Kodamaea ohmeri SSK and Its Characterization for Degradation of Inhibitors from Lignocellulosic Biomass

Lignocellulosic biomass is widely recognized as a renewable resource for bioconversion. However, the presence of inhibitors such as furfural, 5-HMF, and acetic acid can inhibit cell growth, thereby affecting the overall efficiency of the bioconversion process. The studies on the degradation of lignocellulosic hydrolysate inhibitors by <i>Saccharomyces cerevisiae</i> have been limited. In this research, a yeast strain <i>Kodamaea ohmeri</i> can degrade inhibitors furfural, 5-HMF, and acetic acid, and the genome sequence of the strain was analyzed. Furthermore, the molecular detoxification mechanism of <i>K. ohmeri</i> SSK against lignocellulosic hydrolysate inhibitors was predicted using whole genome sequencing. Annotation based on the COG/KEGG databases identified 57 key detoxification genes, including the alcohol dehydrogenase (ADH) gene, aldo-keto/aldehyde reductase (AKR/ARI) gene, and aldehyde dehydrogenase (ALDH) gene. Stress tolerance experiments revealed that the maximum tolerance concentration for the strain was 5.2 g/L of furfural, 2.5 g/L of 5-HMF, and 5.9 g/L of acetic acid, respectively. A NAD(P)⁺-dependent bifunctional enzyme with possible ADH and ARI activities was found by conserved domain analysis. Phylogenetic analysis indicated that this enzyme shared 99% homology with the detoxification enzyme from <i>S. cerevisiae</i> S288C (GenBank: Q04894.1). This study represents the first comprehensive analysis of the inhibitor detoxification network in <i>K. ohmeri</i> SSK from a genome perspective, providing theoretical targets and design strategies for developing highly efficient biorefinery strains.