Bioethanol from corn meal hydrolyzates

Abstract

The two-step enzymatic hydrolysis of corn meal by commercially available ?-amylase and amyloglycosidase and the subsequent or simultaneous ethanol fermentation of the hydrolyzates by Saccharomyces cerevisiae yeast were studied. The conditions of starch hydrolysis, such as substrate and enzyme concentration and the time required for enzymatic action, were optimized taking into account both the effects of hydrolysis and ethanol fermentation. The corn meal hydrolyzates obtained were good substrates for ethanol fermentation by Saccharomyces cerevisiae. A yield of ethanol of more than 80% of the theoretical one was achieved with a satisfactory product to substrate yield Yp/s (g/g) and good ethanol volumetric productivity P (g/lh). No shortage of fermentable sugars was observed during simultaneous hydrolysis and fermentation. Savings in time and energy could be realized by such a process.U radu je ispitivan postupak dvojno enzimske hidrolize kukuruznog brasna pomocu komercijalnih enzima ?-amilaze i amiloglukozidaze i naknadna ili uporedna fermentacija hidrolizata pomocu kvasca Saccharomyces cerevisiae. Uslovi hidrolize kao sto su koncentracija supstrata i enzima i vreme dejstva pojedinih enzima su optimizovani sa aspekta oba procesa (i fermentacije i hidrolize). Dobijeni hidrolizati kukuruznog brasna su se pokazali kao pogodni supstrati za etanolnu fermentaciju pomocu kvasca Saccharomyces cerevisiae pri cemu je ostvaren prinos etanola od vise od 80% od teorijskog prinosa i sa zadovoljavajucim vrednostima prinosa produkta po substratu Yp/s (g/g) i volumetrijske produktivnoosti P (g/lh). U toku postupka sa uporednim odvijanjem hidrolize i fermentacije nije primecen nedostatak fermentabilnih secera. Osim toga ovim postupkom moguce je skratiti ukupno vreme procesa i ostvariti odredjene energetske ustede.