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

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.Electronic supplementary materialThe online version of this article (10.1186/s13568-017-0507-x) contains supplementary material, which is available to authorized users.

Research Progress of Fermented Functional Foods and Protein Factory-Microbial Fermentation Technology

“…Among different microorganisms, Fusarium venenatum is the most prevalent species to be successfully utilized in food industry, and it has been applied to produce mycoprotein as food being under the trade name Quorn, and mycoprotein indicates satiation characteristics which can be a solution for obesity by enabling people to obtain a healthier diet with low fat and high fiber content [215]. It has been reported that Vitreoscilla hemoglobin has profitable advantages on improving total protein secretion and cellulase activity of Trichoderma reesei in submerged fermentation [216]. Benefits and disadvantages of Solid State Fermentation and Submerged Fermentation are presented in Table 2.…”

Biotechnological Micronutrient Production: Recombinant DNA Technology-Based Vitamin A Synthesis

“…Many bacteria and fungi have been genetically engineered to express the vgb gene to improve metabolite production including metabolites such as L-DOPA, dopamine (Kurt, Aytan, Ozer, Ates & Geckil, 2009), vitamine E (Giray, 2020), phenazine (Kahraman, Aytan, Giray & Özcan, 2013) arachidonic acid (Zhang, Feng, Cui & Song, 2017), penicillin (Li, Li, Zhou, Zhao & Zhu, 2006), hypocrellin and amylase production (Gao, Deng, Guan, Liao & Cai, 2018), flavones (Zhu, Sun & Zhang, 2011), ganoderic acid (Li et al, 2016a), cellulase (Lin et al, 2017), protease and chitinase (Zhang et al, 2014). In this study, the effect of both VHb gene and various environmental conditions such as glucose, fructose, and sucrose on the production of vitamin A was investigated.…”

Improving Hypoxia Adaption Causes Distinct Effects on Growth and Bioactive Compounds Synthesis in an Entomopathogenic Fungus Cordyceps militaris

“…The transformation of VHb has been confirmed to efficiently relief hypoxia stress in bacteria (Horng et al, 2010), yeasts (Wu and Fu, 2012), plants (Jokipii et al, 2008), and animals (Pendse and Bailey, 1994). Recently, many reports have verified that this strategy also works as an O 2 conveyor and transporter in filamentous fungi (Lin et al, 2017;Wang et al, 2019;Xu et al, 2019). Sterol regulatory element binding proteins (SREBPs) are also required for adaptation to hypoxic environment in fungi (Bien and Espenshade, 2010;Gutierrez et al, 2019).…”