Ethanol fermentation of energy beets by self-flocculating and non-flocculating yeasts

Ningning Zhang; V Steven Green; Xumeng Ge; Brett J Savary; Jianfeng Xu

doi:10.1016/j.biortech.2013.12.081

Ethanol fermentation of energy beets by self-flocculating and non-flocculating yeasts

Bioresour Technol. 2014 Mar:155:189-97. doi: 10.1016/j.biortech.2013.12.081. Epub 2013 Dec 27.

Authors

Ningning Zhang¹, V Steven Green², Xumeng Ge¹, Brett J Savary³, Jianfeng Xu⁴

Affiliations

¹ Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR 72401, USA.
² College of Agriculture and Technology, Arkansas State University, Jonesboro, AR 72401, USA.
³ Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR 72401, USA; College of Agriculture and Technology, Arkansas State University, Jonesboro, AR 72401, USA. Electronic address: bsavary@astate.edu.
⁴ Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR 72401, USA; College of Agriculture and Technology, Arkansas State University, Jonesboro, AR 72401, USA. Electronic address: jxu@astate.edu.

PMID: 24462879
DOI: 10.1016/j.biortech.2013.12.081

Abstract

Specialized varieties of sugar beets (Energy Beets™) are being developed for producing industrial sugars in Arkansas' Mississippi River Delta. To evaluate their suitability for producing regional fermentation feedstocks, we report initial cultivation trials and ethanol fermentation of raw beet juice and combined juice with pulp mash (JPM) liquefied with enzymes, comparing ethanol yields under different regimes by self-flocculating and non-flocculating yeasts. Nine varieties produced root yields averaging 115Mg/ha and 18.5% sucrose contents. Raw beet juice fermentation yielded ethanol up to 0.48g/g (sugar). JPM was directly fermented through either a sequential (SeqSF) or simultaneous saccharification and fermentation (SSF) process. For both yeast types, SSF was a more efficient process than SeqSF, with ethanol yields up to 0.47g/g (sugar) and volumetric productivity up to 7.81g/L/h. These results indicate the self-flocculating yeast is suitable for developing efficient bioprocesses to ferment industrial sugar from energy beets.

Keywords: Beta vulgaris; Bioethanol; Industrial sugar; Saccharification; Self-flocculating yeast.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Agriculture / methods*
Analysis of Variance
Arkansas
Beta vulgaris / metabolism*
Biofuels*
Ethanol / metabolism*
Fermentation
Flocculation
Industrial Microbiology / methods
Yeasts / metabolism*

Substances

Biofuels
Ethanol