Suspension characteristics of semi-hydrophobic cryogel beads and their application in Lactobacillus paracasei cell immobilization for organic acid production
In order to solve the problems of substrate and product inhibition,low cell density and organic acid tolerance,poly(hydroxyethyl methacrylate-butyl methacrylate)semi-hydrophobic cryogel beads were prepared by"crystallization pore-forming and low temperature polymerization",and their suspension behaviors in a 10 L stirred bioreactor were investigated by high-speed imaging and numerical simulation.Lactic acid and phenyllactic acid biosynthesis processes were studied using these cryogel bead immobilized Lactobacillus.The results show that the suspension characteristics of the cryogel beads obtained by numerical simulation are consistent with those of high-speed imaging,and the minimal stirring rate required for uniform suspension of cryogel beads(volume fraction is 3%)is 55 r·min-1.The Lactobacillus biomass reached 10.5 g·L-1 in the co-production process of lactic acid and phenyllactic acid,which was increased by 84.2%compared with Lactobacillus fermentation without immobilization.During the first feeding period,the fermentation period of lactic acid was greatly shortened to 21 h,which was 50%shorter than that without immobilization.
semi-hydrophobic cryogel beadstirred tank bioreactorsuspension behaviorLactobacillusfermentationnumerical simulation
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