Performing under pressure: esterification activity of dry fermented solids in subcritical and supercritical CO
2.
Biotechnol Lett 2020;
43:503-509. [PMID:
33051809 DOI:
10.1007/s10529-020-03029-2]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 10/09/2020] [Indexed: 10/23/2022]
Abstract
OBJECTIVE
Lipases are often used in immobilized form, but commercial immobilized lipases are costly. An alternative is to produce lipases in solid-state fermentation, dry the solids and then use the "dry fermented solids" (DFS) directly. We produced DFS by growing Burkholderia contaminans on a mixture of sugarcane bagasse and sunflower seed meal and used the DFS to esterify oleic acid with ethanol in subcritical and supercritical CO2 at 40 °C.
RESULTS
Compared to a control without CO2 at atmospheric pressure, subcritical CO2 at 30 bar improved esterification activity 1.2-fold. Higher pressures, including supercritical pressures up to 150 bar, reduced activity to less than 80% of the control. At 30 bar, the esterification activity was improved a further 1.8-fold with the addition of 9% water (i.e. 9 g water per 100 g oleic acid) to the reaction medium.
CONCLUSION
A subcritical CO2 atmosphere, with the addition of a small amount of water, improved the esterification activity of DFS containing lipases of Burkholderia contaminans.
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