Simultaneous saccharification and fermentation of wheat bran flour into ethanol using coculture of amylotic Aspergillus niger and thermotolerant Kluyveromyces marxianus
- 212 Downloads
Studies on simultaneous saccharification and fermentation (SSF) of wheat bran flour, a grain milling residue as the substrate using coculture method were carried out with strains of starch digesting Aspergillus niger and nonstarch digesting and sugar fermenting Kluyveromyces marxianus in batch fermentation. Experiments based on central composite design (CCD) were conducted to maximize the glucose yield and to study the effects of substrate concentration, pH, temperature, and enzyme concentration on percentage conversion of wheat bran flour starch to glucose by treatment with fungal α-amylase and the above parameters were optimized using response surface methodology (RSM). The optimum values of substrate concentration, pH, temperature, and enzyme concentration were found to be 200 g/L, 5.5, 65°C and 7.5 IU, respectively, in the starch saccharification step. The effects of pH, temperature and substrate concentration on ethanol concentration, biomass and reducing sugar concentration were also investigated. The optimum temperature and pH were found to be 30°C and 5.5, respectively. The wheat bran flour solution equivalent to 6% (w/V) initial starch concentration gave the highest ethanol concentration of 23.1 g/L after 48 h of fermentation at optimum conditions of pH and temperature. The growth kinetics was modeled using Monod model and Logistic model and product formation kinetics using Leudeking-Piret model. Simultaneous saccharificiation and fermentation of liquefied wheat bran starch to bioethanol was studied using coculture of amylolytic fungus A. niger and nonamylolytic sugar fermenting K. marxianus.
Keywordssimultaneous saccharification and fermentation (SSF) starch coculture fermentation statistical experimental design bioethanol Monod model
Unable to display preview. Download preview PDF.
- 1.Roble N D, Ogbonna J C, Tanaka H. A novel circulating loop bioreactor with cell immobilized in loofa (Luffa cylindrical) sponge for the bioconversion of raw cassava starch to ethanol. Appl Microbiol Biotechnol, 2002, 60: 671–678Google Scholar
- 3.Neves M A D, Kimura T, Shimizu N. Production of alcohol by simultaneous saccharification and fermentation of low grade wheat flour. Brazilian Arch Biol Technol, 2006, 49: 481–190Google Scholar
- 10.Ratnam Bandaru V V, Subba Rao S, Raomendu D, Narasima Rao M, Chityala A. Optimization of fermentation condition for the production of ethanol from sago starch by co-immobilized amyloglucosidase and cells of Zymomonas mobilis using response surface methodology. Enzym Microbiol Technol, 2006, 38: 209–214CrossRefGoogle Scholar
- 11.Sunitha I, Subba Rao M V, Ayyanna C. Optimization of medium components and fermentation conditions for production of L-glutamic acid by co-immobilized whole cells of Micrococcus glutanicus and Pseudomonas reptilivora. Bioproces Eng, 1998, 18: 353–359Google Scholar
- 16.Bailey J E, ed. Kinetics of substrate utilization, product formation and biomass production in cell cultures. In: Biochemical Engineering Fundamentals, 3rd edition. New York: McGraw Hill Book Company, 1986Google Scholar
- 17.Aiba S, ed. Biochemical Engineering: Comprehensive text on fermentation of batch kinetics. In: Biochemical Engineering, 2nd edition. New York: Academic Press Inc, 1973Google Scholar