Optimizing medium for producing ethanol from industrial crop Jerusalem artichoke by one-step fermentation and recombinant Saccharomyces cerevisiae

Abstract

In order to obtain a high ethanol yield from the Jerusalem artichoke raw extract and reduce the fermentation cost, we have engineered a new recombinant Saccharomyces cerevisiae strain that could produce ex-inulinase. The response surface methodology based on Plackett–Burman and Box–Behnken design was used to optimize the medium for the ethanol production from the Jerusalem artichoke raw extracts by the recombinant strain. In the first optimization step, Plackett–Burman design was employed to select significant factors, including concentrations of yeast extract, inoculum, and MgSO₄·7H₂O. In the second step, the steepest ascent experiment was carried out to determine the center point with the three significant factors; the selected combinations were further optimized using the Box–Behnken design. The maximum ethanol production rate was predicted at 91.1 g/l, which was based on a medium consisting of yeast extract 9.24 g/l, inoculum 39.8 ml/l, and MgSO₄·7H₂O 0.45 g/l. In the validating experiment, the ethanol fermentation rate reached 102.1 g/l, closely matching the predicted rate.

Keywords::

• RSM
• optimization
• Jerusalem artichoke
• energy
• Saccharomyces cerevisiae
• one-step fermentation

Additional information

Funding

Funding

The authors are grateful for the financial support of the National Key Projects of Scientific and Technical Support Programs funded by the Ministry of Science and Technology of Jiangsu Province [grant number BE2011368]; the Ministry of Science and Technology of China [grant number 2011BAD13B09]; Fundamental Research Funds for Central Universities [grant number Y0201100249]; the New Teachers' Fund for Doctor Stations, Ministry of Education [grant number 20100097120016]; the Project of a Special Fund for Public Welfare Industrial (Agriculture) Research of China [grant number 200903001-5]; One Hundred-Talent Plan of Chinese Academy of Sciences (CAS), the CAS/SAFEA International Partnership Program for Creative Research Teams, the Science and Technology Development Plan of Shandong Province [grant number 2010GSF10208]; the Yantai Science and Technology Development Project [grant number 2011016] and Yantai Double-hundred High-end Talent Plan [grant number XY-003-02]; and 135 Development Plan of YIC-CAS.