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Utilizing Crude Waste Glycerol in the Biorefinery: Glycerol Gels for in Situ Substrate Delivery to Whole Cell Biocatalysts

Bothwell, Kyra M., Krasňan, Vladimír, Lorenzini, Fabio, Rebroš, Martin, Marr, Andrew C., Marr, Patricia C.
ACS sustainable chemistry & engineering 2019 v.7 no.11 pp. 9948-9956
Escherichia coli, biocatalysis, biocatalysts, biomass, biorefining, cell growth, fermentation, gels, glycerol, protein synthesis, recombinant proteins, silica gel, sol-gel processing, toxicity, wastes
Sol–gel methods were used to facilitate the in situ controlled delivery of glycerol as a substrate for whole cell biocatalysis. The entrapment of the polyol within a silica gel matrix enabled the utilization of crude and moderately toxic bioderived substrates that could not be used in fed-batch mode. Different grades of glycerol were incorporated in gels and fed to C. butyricum for 1,3-propanediol production and to E. coli for recombinant protein production. Of particular note was the successful use of crude glycerol gels with E. coli. By virtue of gel immobilization, previously toxic crude glycerol samples were rendered active, and the use of gel technologies was therefore shown to expand the range of biomass that can be utilized in whole cell biocatalytic processes. Specific matching of the acid used in the gel synthesis with the fermentation medium further supported cell growth.