Author : Gulten Izmirlioglu
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (971 download)
Book Synopsis Simultaneous Saccharification and Fermentation of Waste Potato Mash to Ethanol by Aspergillus Niger and Saccharomyces Cerevisiae in Biofilm Reactors by : Gulten Izmirlioglu
Download or read book Simultaneous Saccharification and Fermentation of Waste Potato Mash to Ethanol by Aspergillus Niger and Saccharomyces Cerevisiae in Biofilm Reactors written by Gulten Izmirlioglu and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Bioethanol production is of great interest to meet the renewable energy demand and reduce the negative environmental impacts of petroleum fuel while providing energy security for countries. In order to make ethanol production cost-competitive, inexpensive, and easily available feedstocks are needed as well as novel processing technologies with higher productivities. Industrial wastes are of great interest as a substrate in production of value-added products to reduce the cost, while managing the waste economically and environmentally. Therefore, bio-ethanol production from industrial wastes has gained attention because of its abundance, availability, and rich carbon and nitrogen content. Part of the production cost also includes cost of the enzymes needed for the saccharification step during the starch hydrolyzation, which can be a significant cost depending on the enzymes performances. On the other hand, to achieve high productivity, medium optimization, culture conditions, integrated fermentation methods, and reactor design should be considered. Thus, novel approaches for bioethanol production from starchy industrial wastes have gained attention not only to reduce the production cost, but also to maximize the ethanol productivity. This dissertation aimed to reduce the cost of ethanol production with utilization of starchy waste of potato industry, and evaluate the simultaneous saccharification and fermentation process with a fungal co-culture to eliminate purchased enzyme costs, and, finally, to increase the productivity of ethanol fermentation, in particular by cell immobilization in biofilm reactors. Therefore, medium optimization for co-culture was considered to improve production of ethanol in this study, which was neglected for co-culture so far in the literature. Furthermore, first time simultaneous saccharification and fermentation by co-culture in biofilm reactors was employed to achieve the goal.Glucoamylase is one of the most common enzymes used in the starch industry to break down the starch into its monomers. Glucoamylase production and its activity are highly dependent on medium composition. Therefore, in this study, medium optimization for glucoamylase production was considered to improve the glucoamylase activity. Four fungi were screened for amylase production, and Aspergillus niger van Tieghem was found to be the best glucoamylase-producing fungus. Then, a statistical design, Plackett-Burman design, was used to screen various medium ingredients for glucoamylase production by A. niger, and malt extract, FeSO47H2O, and CaCl22H2O were found to have significant effects on the glucoamylase production. Finally, malt extract, FeSO47H2O, and CaCl22H2O were optimized by using another statistical design, response surface methodology. The results showed that the optimal medium composition for A. niger van Tieghem was 50 g/L of industrial waste potato mash supplemented with 51.82 g/L of malt extract, 9.27 g/L of CaCl22H2O, and 0.50 g/L of FeSO4 7H2O . At the end of the optimization, glucoamylase activity and glucose production were improved 126 and 98% compared to only industrial waste potato mash basal medium and 274.4 U/ml glucoamylase activity and 41.7 g/L glucose levels were achieved, respectively. Additionally, the effect of various medium components on ethanol production by Saccharomyces cerevisiae was evaluated. Yeast extract, malt extract, and MgSO47H2O showed significantly positive effects among the screened medium components, whereas KH2PO4 and CaCl22H2O had a significantly negative effect (p-value
