Simultaneous saccharification and fermentation of pretreated corn cobs by fungus Mucor indicus

U ovom radu proveden je proces simultane enzimske saharifikacije i fermentacije ispranog i usitnjenog čvrstog dijela zaostalog nakon kiselinske predobrade kukuruznih oklasaka. U cilju uspješne provedbe procesa istražen je utjecaj dva različita enzimska pripravka (Cellulase Blend-a i Viscozyme-a) u koncentraciji od 10 % (vol/vol) te njihove kombinacije, 2 % (vol/vol) Cellulase Blend i 5 % (vol/vol) Viscozyme na iskorištenje hidrolize glukana, ksilana i ukupnih ugljikohidrata korištene sirovine. Najviši stupanj hidrolize glukana (100 %) i ukupnih ugljikohidrata (89,90 %) dobiven je uz 10 % (vol/vol) Cellulase Blend na 40 °C u hranjivoj podlozi, a ksilana (93,51 %) uz 10 % (vol/vol) Viscozyme pri 40 °C u puferu. Kako bi se ispitao utjecaj temperature i podloge na uspješnost procesa proizvodnje bioetanola pomoću plijesni M. indicus proveden je aerobni uzgoj u Erlenmayer tikvicama tehnikom simultane enzimske saharifikacije i fermentacije na 30 i 40 °C u puferu i podlozi. Najveća uspješnost procesa proizvodnje etanola zabilježena je kod uzgoja u podlozi uz dodatak 4 % (vol/vol) Cellulase Blend-a pri 30 °C, a produktivnost je iznosila 0,0939 g L-1 h-1. U istim uvjetima te uz dodatak istog enzimskog pripravka koncentracije 4 % (vol/vol) proveden je uzgoj M. indicus u bioreaktoru s miješalom, a produktivnost je nakon 22 h uzgoja iznosila 0,1432 g L-1 h-1. Nakon uzgoja provedena je izolacija glukozamina.In this paper, the procedure of simultaneous saccharification and fermentation of washed and shredded solid residues after dilute acid pretreatment of corn cobs was performed. In order to successfully carry out the process, the effect of two different enzyme blends (Cellulase Blend and Viscozyme at a concentrations of 10 % (vol/vol)) and their combination, 2 % (vol/vol) Cellulase Blend and 5 % (vol/vol) Viscozyme) on the efficiency of hydrolysis of glucan, xylan and total carbohydrates of the raw material used was investigated. The highest degree of hydrolysis of glucan (100 %) and total carbohydrates (89.90 %) was obtained with a 10 % (vol/vol) Cellulase Blend at 40 °C in the matrix which simulates the broth, and xylan (93.51 %) with 10 % (vol/vol) Viscozyme at 40 °C in acetate buffer. In order to examine the influence of temperature and media on the success of the bioethanol production process by M. indicus, aerobic cultivation was performed in Erlenmayer flasks by the technique of simultaneous enzymatic saccharification and fermentation at 30 and 40 °C in two different broths. The highest bioprocess productivity of 0.0939 g L-1 h-1 was observed in broth with the addition of 4 % (vol/vol) Cellulase Blend at 30 °C. M. indicus was grown in a stirred tank bioreactor under the same conditions and with the addition of the same enzyme blend at a concentration of 4 % (vol/vol). After 22 hours of cultivation the productivity reached value of 0.1432 g L-1 h-1. The isolation of glucosamine was performed after cultivation