Process design of ethanol production system from a semi-solid mixture of raw cassava starch, Rhizopus sp. and S. cerevisiae by simultaneous saccharification, fermentation and stripping. Thesis (M.Sc.)
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TextLanguage: English Publication details: Los Baños, Laguna, PH University of the Philippines at Los Baños 1988Description: 145 pSubject(s): LOC classification: - 42218
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CIAT Library Document collection CINFOS | Document Collection CINFOS | 42218 (Browse shelf(Opens below)) | c.1 | Short Loan | 100067452 |
A broad study on the process development of an ethanol production system for raw cassava starch has been tackled starting from the screening of the microorganisms towards the development of process designs of the fermentation and ethanol dehydration systems. Results showed that the best fungal strain capable of digesting raw starch was Rhizopus strain cultured by the solid substrate koji method. The better additives for the rice bran culture media was 0.5 percent ipil-ipil sawdust and 1 percetn sweet potato starch giving optimum glucoamylase enzyme productions at 6 days of culture time. Saccharification process using mini- bioreactors registered optimum conditions for koji as: 215 g/l substrate, 215 g/l enzyme, 1.5 l/min/l broth air flowrate and 50 degrees C temp. During saccharification process, the highest reducing sugar produced was about 100 g/l, the koji registering higher production than the same enzyme level of amyloglucosidase. Simultaneous saccharificaion and fermentation expt. gave a max. ethanol production of about 11 percent (v/v) at 3 days fermentation at the optimum substrate level of not more than 265 g/l. Higher substrate level causes inhibition of reaction which has been eliminated by an ethanol stripping and rectifying system. Upon rectification process, the av. ethanol concn. of the condensate was 285 g/l which has been obtained using Rhizopus koji and the initial starch substrate concn. increased to 400 g/l. The results using koji were higher than that of the results by amyloglucosidase. It was shown that the ethanol recovery at higher concn. was possible. Attempts of the dehydration of hydrous ethanol by absorption of the water in the ethanol-water vapor mixture through a cassava starch packing has been found to be feasible at a low temp. (40 degrees C) and by using raw cassava strach particles. (AS) eng