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The defense date of the thesis is 2006-08-15
The current date is 2019-02-18
URN etd-0815106-205028 Statistics This thesis had been viewed 1611 times. Download 5 times. Author Chien-Yu Chang Author's Email Address No Public. Department Bioengineering Year 2005 Semester 2 Degree Master Type of Document Master's Thesis Language English Page Count 62 Title Production of L-Lactic Acid By Culture of Rhizopus arrhizus Keyword Rhizopus arrhizus mycelial pellet lactic acid production bioreactor bioreactor lactic acid production mycelial pellet Rhizopus arrhizus Abstract Pellet-form Rhizopus arrhizus was cultured in a stirred tank bioreactor for enhanced L-lactic acid production using glucose as substrate and an ammoniacal solution as neutralizing agent. Ammonium hydroxide may cause damage to fungal cells in terms of “chemical burn”, leading to a poor production of lactic acid. It was found when ammonium bicarbonate was added to the ammonia water or urea was added to the culture medium, the toxicity of ammonium hydroxide decreased and lactic acid production was enhanced. The fermentation was carried out at pH 5.0 with the addition of 1 g L–1 urea in the culture medium, using an ammoniacal solution as neutralizing agent, which was 2% (w/v) ammonium bicarbonate in 10% (w/v) ammonia water. The batch fermentation completed in 48 h. The final concentration of lactic acid was 98 g L–1 with a yield of 82%. However, the final concentrations of lactic acid obtained in the first four cycles of repeated batch fermentation were 98, 95, 88 and 82 g L–1, with fermentation times being 48, 48, 52 and 54 h, respectively. Advisor Committee Dey-Chyi Sheu - advisor
Files Date of Defense 2006-07-20 Date of Submission 2006-08-15