Enhancing xylanase expression by Komagataella phaffii by formate as carbon source and inducer.

Komagataella phaffii (syn. Pichia pastoris), a methylotrophic yeast, has many advantages as a protein expression system, but has the disadvantage of hazardous methanol as an inducer and carbon source. To enable substitution of formate for methanol, a formate assimilation pathway was constructed by the co-expression of acetyl-CoA synthase, acetaldehyde dehydrogenase, and transcription factor Mit1, resulting in a 103.5 ± 12.5% increase in xylanase production. Recombinant K. phaffii was able to use formate as a carbon source, indicating successful substitution of formate for methanol. Xylanase production, using the safe and sustainable formate as an inducer and carbon source, is a major advance in the field of industrial enzyme production. KEY POINTS: • Change to formate assimilation by recombinant K. phaffii instead of methanol • K. phaffii expressed xylanase by formate induction instead of methanol induction • Increased xylanase expression by transcription factor co-expression.