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Repeated batch fermentation for surfactin production with immobilized Bacillus subtilis BS‐37: two‐stage pH control and foam fractionation
Author(s) -
Yi Gaobin,
Liu Qiang,
Lin Junzhang,
Wang Weidong,
Huang He,
Li Shuang
Publication year - 2017
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.5028
Subject(s) - surfactin , fermentation , bacillus subtilis , fractionation , chemistry , foam fractionation , chromatography , pulp and paper industry , biomass (ecology) , yield (engineering) , volume (thermodynamics) , food science , bacteria , biochemistry , materials science , biology , pulmonary surfactant , agronomy , genetics , engineering , metallurgy , physics , quantum mechanics
BACKGROUND Surfactin, a lipopeptide biosurfactant produced by Bacillus strains, is one of the most surface‐active biosurfactants, and has the potential to enhance oil recovery or environmental remediation. However, low yield and high production costs limit its use in high‐volume applications. In this work, Bacillus subtilis BS‐37 was immobilized on a piece of cotton towel in a 5 L stirred tank reactor; the fill‐and‐draw process and foam fractionation were used for repeated batch fermentations. A two‐stage pH control operation was developed for surfactin fermentation: for repeated batch fermentation, the pH value was 5.0 for the biomass accumulation in the previous 6 h; and then the pH value was raised to 7.5 for surfactin production over the following 18 h of fermentation. RESULTS The immobilized Bacillus subtilis BS‐37 cells were efficiently reused for 7 cycles, producing 7887.3 mg surfactin in total. CONCLUSIONS The repeated batch fermentation, low‐cost foam fractionation, reusable immobilized cells, and energy‐efficient open (nonsterile) fermentation could greatly promote the development of industrial production of surfactin. © 2016 Society of Chemical Industry