Single cell protein production of co-culture Kodamaea ohmeri and Lactococcus lactis in corn straw hydrolysate

With the world population continuously increasing, the protein demand will double by 2050. Single cell protein (SCP) derived from lignocellulosic biomass offers a sustainable solution. Many inhibitors are produced during the pretreatment process of lignocellulosic biomass. Inhibitor-rich hydrolysates limit microorganisms cell growth and SCP yields. In this work, we report a co-culture consortium of Kodamaea ohmeri SSK (pentose-utilizing yeast) and Lactococcus lactis LX (probiotic bacterium) that efficiently converts real corn straw hydrolysate into SCP. K. ohmeri SSK can tolerate inhibitors such as furfural, 5-hydroxymethylfurfural (5-HMF), and acetic acid and consume glucose, xylose, and arabinose in real hydrolysate. L. lactis LX showed less growth in monoculture than that of co-culture. The total amino acid content from co-cultured K. ohmeri SSK and L. lactis LX was increased to 331.42 mg/g crude protein, but that of monocultured K. ohmeri SSK was 309.89 mg/g crude protein containing 17 amino acids. This work demonstrates a symbiotic microbial platform can produce SCP from non-detoxified lignocellulosic biomass. The co-culture robust inhibitor tolerance and balanced amino acid profile highlight its potential for industrial-scale protein production. These results will represent an attractive choice cell factory for lignocellulosic substrate utilization and provide a platform for biomass conversion to SCP.