Improving cellulase production in submerged fermentation by the expression of a Vitreoscilla hemoglobin in Trichoderma reesei

AMB Express

Xiuzhen Chen¹  Xiamei Zhang¹  Bingran Song¹  Wei Xue¹  Zhiyang Dong¹  Jie Lin¹  Xiaoyun Su² 

[1] Institute of Microbiology, Chinese Academy of Sciences;Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences;

关键词: Trichoderma reesei;    Vitreoscilla hemoglobin;    Submerged fermentation;    Oxygen limitation;    Cellulase;   

DOI  :  10.1186/s13568-017-0507-x

来源: DOAJ

【 摘 要 】

Abstract Trichoderma reesei is well known as an industrial workhorse fungus in cellulase production. The low dissolved oxygen supply in the highly viscous medium of T. reesei remains a major bottleneck that hampers growth and cellulase production in submerged fermentation. Vitreoscilla hemoglobin (VHb) has been demonstrated to improve metabolism and protein production in different heterologous hosts under hypoxic conditions, but the use of VHb in T. reesei remains uninvestigated. This study examines the effect of VHb in improving T. reesei performance in submerged fermentation. The VHb gene (vgb)-expressing cassette was successfully transformed into the TU-6 strain, integrated into the genome of T. reesei, and functionally expressed with biological activity, which was confirmed by carbon monoxide difference analysis. Compared to the parent strain, the expression of VHb increased the glucose consumption rate of the transformant. Moreover, in cellulase-inducing medium total protein secretion of the VHb expressing strain was 2.2-fold of the parental strain and the filter paper cellulase activity was increased by 58% under oxygen-limiting conditions. In summary, our results demonstrate that VHb has beneficial effects on improving total protein secretion and cellulase activity of T. reesei in submerged fermentation.

【 授权许可】

Unknown