A novel wild-type Saccharomyces cerevisiae strain TSH1 in scaling-up of solid-state fermentation of ethanol from sweet sorghum stalks

PLoS One. 2014 Apr 15;9(4):e94480. doi: 10.1371/journal.pone.0094480. eCollection 2014.

Abstract

The rising demand for bioethanol, the most common alternative to petroleum-derived fuel used worldwide, has encouraged a feedstock shift to non-food crops to reduce the competition for resources between food and energy production. Sweet sorghum has become one of the most promising non-food energy crops because of its high output and strong adaptive ability. However, the means by which sweet sorghum stalks can be cost-effectively utilized for ethanol fermentation in large-scale industrial production and commercialization remains unclear. In this study, we identified a novel Saccharomyces cerevisiae strain, TSH1, from the soil in which sweet sorghum stalks were stored. This strain exhibited excellent ethanol fermentative capacity and ability to withstand stressful solid-state fermentation conditions. Furthermore, we gradually scaled up from a 500-mL flask to a 127-m3 rotary-drum fermenter and eventually constructed a 550-m3 rotary-drum fermentation system to establish an efficient industrial fermentation platform based on TSH1. The batch fermentations were completed in less than 20 hours, with up to 96 tons of crushed sweet sorghum stalks in the 550-m3 fermenter reaching 88% of relative theoretical ethanol yield (RTEY). These results collectively demonstrate that ethanol solid-state fermentation technology can be a highly efficient and low-cost solution for utilizing sweet sorghum, providing a feasible and economical means of developing non-food bioethanol.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biofuels / microbiology
  • Cost-Benefit Analysis
  • Ethanol / metabolism*
  • Fermentation*
  • Saccharomyces cerevisiae / growth & development
  • Saccharomyces cerevisiae / metabolism*
  • Sorghum / metabolism*

Substances

  • Biofuels
  • Ethanol

Grants and funding

This work was financially supported by grants from the Ministry of Science and Technology (2012DFG61720, 2011BAD22B03), the low carbon energy university alliance project, and the Public Science and Technology Research Funds Projects of Ocean (201005031). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.