大肠杆菌L-丝氨酸脱水酶的表达改善甘氨酸营养缺陷型毕赤酵母L-丝氨酸的生长OA北大核心CSTPCD

Amino acids cannot be rapidly utilized by microorganisms as a gradually metabolized carbon source.L-serine dehydratase(L-SerDH)catalyzes the one-step conversion of L-serine into pyruvate and ammonia,facilitating central carbon metabolism to generate bi-omass without the consumption of ATP and reducing power.L-serine is a key intermediate in the formate utilization pathway(reductive gly-cine pathway).Therefore,improving the utilization of L-serine can provide valuable insights into the utilization of formate and serine as carbon sources.This paper explored serine tolerance of Pichia pastoris.Results demonstrated that P.pastoris exhibited tolerance to 20 g/L of L-serine.Expression optimization of endogenous L-serine dehydratase was carried out in P.pastoris.Eight heterologous L-serine de-hydratases were expressed separately in glycine auxotroph P.pastoris.The results indicated that L-SerDH encoded by the E.coli tdcG gene had the best effect on the improvement of serine utilization,with the final OD600 increased to 1.6-fold that of the original strain.This study represents the validation of L-serine tolerance in P.pastoris and screens a superior source of L-serine dehydratase.These findings offer valu-able insights into enhancing enzyme sources for serine utilization in P.pastoris.