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119 Improvement of Bioethanol Production by Zygomycete Fungi using Fungal extract Reihaneh Asachi asachi@ce iut ac ir Date of Submission 2013 05 29 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree DOCTOR OF PHILOSOPHY Language Farsi Supervisor Keikhosro Karimi karimi@cc iut ac ir Abstract Ethanol from renewable resources has been of interest in recent decades as an alternative fuel or oxygenated additive to current fossil fuels Bioethanol can be produced by fermentation from a variety of raw materials which contain sugars starch and lignocellulosic substances One of the most important parts of the process of producing ethanol by fermentation is using microorganisms A great number of yeasts and fungi are used in the fermentation industry Zygomycetes are saprophytic filamentous fungi which are able to produce several metabolites including ethanol and glycerol Among the filamentous fungi belonging to the zygomycetes class Mucor indicus showed good performances on ethanol productivity Beside the production of ethanol the biomass of this fungus contains appreciated level of chitosan which is a valuable product Previous studies have shown that despite the ability of this fungus to produce ethanol the fungus requires a variety of nutrients including yeast extract which is expensive In the current work for the first time we studied the effects of substitution of fungal extract essential and digestible nutrients produced by autolysis of Mucor biomass instead of the required nutrients yeast extract and minerals for bioethanol production The results showed that fungal extract can lonely replace yeast extract and mineral salts magnesium sulfate potassium hydrogen phosphate ammonium sulfate and calcium chloride in the culture medium and as a rich nutrient can be used in the fermentation process to produce ethanol with high yield of g per g of glucose Autolysis process at C pH and the initial biomass concentration of g L produced a valuable and important source of nutrient as fungal extract Amino nitrogen and total nitrogen concentration of produced fungal extract were equivalent to a concentration of and g L of yeast extract solution respectively The chitosan content of AIM alkali insoluble solids from residual cellular materials signifacantly increased compared to the initial chitosan in fungal biomass AIM which can be considered as a valuable product In this study feasibility of using fungal extract as a nutrient supplement in the fermentation of wheat grains as a starchy biomass at high glucose concentrations by Mucor indicus was also studied The results showed Mucor indicus consumed all the glucose in different media of wheat hydrolysate and g L glucose that in presence of fungal extract and the fermentation time was considerable reduced more than to fold depending on the initial concentration of glucose as well as ethanol with maximum yield was produced In addition possibility of using fungal extract as a nutrient supplement in the fermentation of wheat straw as a lignocellulosic material by Mucor indicus was investigated The results showed that after pretreatment of wheat straw by N methyl morpholine N oxide NMMO the hydrolysis yield increased more than fold and approximately of cellulose in wheat straw was converted to glucose In the presence of fungal extract as a nutrient supplement the highest ethanol yield was obtained to of the maximum theoretical yield during the fermentation of enzymatic hydrolysates from NMMO pretreated wheat straw using M indicus PDF created with pdfFactory trial version www pdffactory com

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