7种抑制物对热带假丝酵母木糖醇发酵性能的影响

在木糖培养基上分别研究7种已知存在于半纤维素水解物中的微生物代谢抑制物(甲酸、乙酸、糠醛、苯甲醛、香草醛、愈创木酚、对羟基苯甲酸)对热带假丝酵母细胞生长及木糖醇发酵性能的影响,并采用二次正交旋转组合设计研究试验中毒性最强的甲酸与香草醛、苯甲醛这3种代表性抑制物共存条件下的抑制效应.结果表明,这些抑制物在低浓度条件下虽然对酵母细胞生长有抑制作用,但是却能使木糖醇比生成速率略有提高.随着抑制物浓度的提高,它们最终均能完全抑制酵母细胞生长,使木糖醇发酵完全不能进行.对酵母细胞生长而言,甲酸与醛类抑制物之间存在毒性相互拮抗作用;对于木糖转化率和木糖醇比生成速率,甲酸和苯甲醛之间存在明显的拮抗作用;对所有考察指标,醛类化合物之间均无显著的拮抗作用,它们之间对酵母细胞的抑制作用呈累加效应.

Influence of Seven Inhibitors on Xylitol Fermen-tability of Candida tropicalis

The influence of seven known inhibitors including formic acid, acetic acid, benzaldehyde, furfural, vanillin, guaiacol and hydroxy acid present in the hemicellulose hydrolysate on the Candida tropics yeast cell growth and the xylitol fermentability was studied respectively, and the inhibitory action of the three inhibitors which were formic acid, vanillin and benzaldehyde under coexistence condition was studied using two orthogonal revolving combination design.The results indicated, the inhibitory action of these inhibitors with low concentration on yeast cell growth was found, but they increase the specific productivities of xylitol slightly. They finally can suppress the yeast cell growth completely along with concentration increasing, cause the xylitol fermentability not to carry on completely.The results also showed that the anti-function mutually between formic acid and aldehyde class inhibitors regarding yeast cell growth, but only the obvious antagonistic effect mutually between formic acid and benzaldehyde regarding xylitol yield from xylose and the specific productivities of xylitol.To all inspection targets, no antagonistic effect found in the aldehyde class compounds, but the inhibitory action of them assumes the accumulation function.