Den Haan Riaan, Rose Shaunita H, Lynd Lee R, van Zyl Willem H
Department of Microbiology, University of Stellenbosch, Stellenbosch 7600, South Africa.
Metab Eng. 2007 Jan;9(1):87-94. doi: 10.1016/j.ymben.2006.08.005. Epub 2006 Sep 16.
In this study, we expressed two cellulase encoding genes, an endoglucanase of Trichoderma reesei (EGI) and the beta-glucosidase of Saccharomycopsis fibuligera (BGL1), in combination in Saccharomyces cerevisiae. The resulting strain was able to grow on phosphoric acid swollen cellulose (PASC) through simultaneous production of sufficient extracellular endoglucanase and beta-glucosidase activity. Anaerobic growth (0.03h(-1)) up to 0.27gl(-1) DCW was observed on medium containing 10gl(-1) PASC as sole carbohydrate source with concomitant ethanol production of up to 1.0gl(-1). We have thus demonstrated the construction of a yeast strain capable of growth on and one-step conversion of amorphous cellulose to ethanol, representing significant progress towards realization of one-step processing of cellulosic biomass in a consolidated bioprocessing configuration. To our knowledge, this is the first report of a recombinant strain of S. cerevisiae growing on pure cellulose.
在本研究中，我们在酿酒酵母中组合表达了两个纤维素酶编码基因，即里氏木霉的内切葡聚糖酶（EGI）和扣囊复膜孢酵母的β-葡萄糖苷酶（BGL1）。通过同时产生足够的细胞外内切葡聚糖酶和β-葡萄糖苷酶活性，所得菌株能够在磷酸膨胀纤维素（PASC）上生长。在含有10g/L PASC作为唯一碳水化合物来源的培养基上观察到厌氧生长（0.03h⁻¹），直至0.27g/L干重细胞，同时乙醇产量高达1.0g/L。因此，我们证明了构建出一种能够在无定形纤维素上生长并将其一步转化为乙醇的酵母菌株，这代表着在实现纤维素生物质在整合生物加工配置中的一步法处理方面取得了重大进展。据我们所知，这是关于酿酒酵母重组菌株在纯纤维素上生长的首次报道。
