Waste glycerol, a by-product of biodiesel production, has been continuously increasing in abundance throughout the world since biodiesel was first commercially produced. Therefore, re-utilization of this waste substance is an important area of research at the present time. This study aims to utilize waste glycerol as a media source for bioethanol production. In addition, Enterobacter aerogenes ATCC 29007, one of the greatest ethanol producers, was immobilized using alginate and a continuous stirred tank reactor (CSTR) newly designed for continuous production with immobilized cells. For efficient bioethanol production, four major media components were statistically optimized by response surface methodology (RSM). The optimal concentrations of each factor were determined: about 6.5 g/L peptone, 3.8 g/L ammonium sulfate, 2.1 g/L citrate dehydrate and 12 g/L waste glycerol. Under the optimal conditions, the ethanol production and yield were about 5.38 g/L and 0.96 mol-ethanol/mol-glycerol with pure glycerol, whereas the ethanol production and yield were approximately 5.29 g/L and 0.91 mol-ethanol/mol-glycerol with the waste glycerol during continuous fermentation. Therefore, the suggested model for media optimization was determined to be reliable. Moreover, continuous ethanol production was successfully performed with waste glycerol using the CSTR system.
Bibliographical noteFunding Information:
This work was supported by the Industrial Strategic Technology Development Program (10051513) funded by the Ministry of Trade, Industry and Energy (MI, Korea) and the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. NRF-2014R1A2A2A01007321). This study was also supported by the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education (NRF-2016R1D1A1A09918327).
© 2017 Elsevier Ltd
- Cell immobilization
- Enterobacter aerogenes
- Response surface methodology
- Waste glycerol
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- General Environmental Science
- Strategy and Management
- Industrial and Manufacturing Engineering