Continuous Ethanol Production from Raw Starch Using a Reversibly Soluble-Autoprecipitating Amylase and Flocculating Yeast Cells

概要

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Direct ethanol production from raw starch was performed continuously using a combination of a reversibly souluble-autoprecipitating amylase (D-AS) in which Dabiase K-27 was immobilized convalently on an enteric coating polymer (hydroxypropyl methylcellulose acetate succinate, AS) as a carrier, and a flocculating yeast. Continuous production was carried out using a reactor equipped with a mixing vessel and a separation vessel. D-AS and the yeast were separated continuously from the product solution by self-sedimentation in the separation vessel and they were utilized repeatedly. In the continuous saccharification of raw starch by D-AS alone, the glucose productivity was about 3.6 g/l/h at a dilution rate (D) of 0.1 h^<-1>. In the continuous ethanol production from raw starch by a combination of D-AS and flocculating yeast cells, high ethanol productivity up to 2.0 g/l/h was achieved at D=0.1 h^<-1>. Although the enzymatic activity of D-AS is inactivated due to insolubilization of the enzyme by the accumulation of NaCl producecd in controlling the pH in the reactor, it is possible to recover the D-AS enzymatic activity by removing the NaCl. This continuous fermentation system suggests a potential for effective ethanol production from raw starch, and it may be widely applicable in heterogeneous culture systems using solid substrates other than raw starch.
社団法人日本生物工学会の論文
1990-04-25