Moremi Mahlatse Ellias, Jansen Van Rensburg Elbert Lukas, La Grange Daniël Coenrad
Department of Biochemistry, Microbiology and Biotechnology, University of Limpopo, Private Bag X1106, Sovenga 0727, South Africa.
Int J Microbiol. 2020 Jul 13;2020:5670936. doi: 10.1155/2020/5670936. eCollection 2020.
Efficient conversion of pentose sugars to ethanol is important for an economically viable lignocellulosic bioethanol process. Ten yeasts fermenting both D-xylose and L-arabinose were subjected to an adaptation process with L-arabinose as carbon source in a medium containing acetic acid. Four -adapted strains were able to ferment L-arabinose to ethanol in the presence of 3 g/L acetic acid at 35°C. Mu 2.2f fermented L-arabinose to produce 3.0 g/L ethanol compared to the parental strain with 1.0 g/L ethanol in the absence of acetic acid. The adapted Mu 2.2f strain produced 3.6 and 0.8 g/L ethanol on L-arabinose and D-xylose, respectively, in the presence of acetic acid while the parental strain failed to grow. In a bioreactor, the adapted Mu 2.2f strain produced 5.7 g/L ethanol in the presence of 3 g/L acetic acid with an ethanol yield and productivity of 0.338 g/g and 0.158 g/L/h, respectively, at a value of 3.3 h. The adapted strain produced 26.7 g/L L-arabitol with a yield of 0.900 g/g at a value of 4.9 h.
将戊糖高效转化为乙醇对于经济上可行的木质纤维素生物乙醇工艺至关重要。十种能发酵D-木糖和L-阿拉伯糖的酵母在含有乙酸的培养基中以L-阿拉伯糖作为碳源进行适应性培养。四种适应菌株能够在35°C、3 g/L乙酸存在的情况下将L-阿拉伯糖发酵为乙醇。与在无乙酸情况下产乙醇1.0 g/L的亲本菌株相比，Mu 2.2f发酵L-阿拉伯糖产生了3.0 g/L乙醇。在有乙酸存在的情况下，适应后的Mu 2.2f菌株在L-阿拉伯糖和D-木糖上分别产生了3.6 g/L和0.8 g/L乙醇，而亲本菌株无法生长。在生物反应器中，适应后的Mu 2.2f菌株在3 g/L乙酸存在的情况下产生了5.7 g/L乙醇，乙醇产率和生产率分别为0.338 g/g和0.158 g/L/h，停留时间为3.3 h。该适应菌株在停留时间为4.9 h时产生了26.7 g/L阿拉伯糖醇，产率为0.900 g/g。
