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Title:	Biobutanol production by a novel local strain of Clostridium acetobutylicum YM1
Authors:	Najeeb Kaid Nasser Al-Shorgani (P63194)
Supervisor:	Aidil Abdul Hamid, Prof. Dr.
Keywords:	Biobutanol production Novel properties Clostridium acetobutylicum Fermentation medium Dissertations, Academic -- Malaysia
Issue Date:	4-Apr-2016
Description:	A potential strain of biobutanol-producing Clostridium was isolated from local soil in Malaysia and characterized by 16S rRNA amplification as Clostridium acetobutylicum YM1. The process parameters to maximize the biobutanol production using a tryptone yeast-extract acetate medium (TYA) showed that the most suitable parameters for the biobutanol production were temperature 30°C, initial pH 6.0±0.2, inoculum size 10% (v/v), C/N ratio 12.8, glucose concentration 50 g/L and ammonium acetate concentration 2 g/L. Further optimization of the process parameters includes glucose concentration, C/N ratio and butyric acid addition by applying the response surface methodology (RSM) with a central composite design (CCD) showed that the optimum conditions were 50 g/L glucose, 8.7 g/L butyric acid and C/N ratio of 65 with iobutanol concentration of 13.82 g/L was produced. Scale up studies in a 5L bioreactor under optimized conditions produced 17.00 g/L biobutanol with 21.71 g/L ABE. A new fermentation medium was further formulated for enhancing the biobutanol production using empirical models including a Plackett-Burman design followed by the steepest ascent design and RSM-CCD. The optimized medium was found to improve the production of biobutanol from 9.50 g/L to 13.67 g/L. The addition of artificial electron carriers to TYA medium in this study resulted in enhancing both the production of biobutanol and biobutanol to acetone ratio (B:A). Benzyl viologen and methyl viologen improved B:A ratio by 800% and 400%, respectively. The addition of 0.1 mM of benzyl viologen at 4 h of cultivation time produced 18.05 g/L biobutanol. Strain YM1 was found to favour the production of biobutanol under uncontrolled pH fermentation. The NADH-dependent butanol dehydrogenase showed a higher degree of activity when the fermentation was run without pH control as compared to the pH control. Hence, the unique feature of strain YM1 is the ability to grow and produce biobutanol in aerobic conditions. Moreover, adding reducing chemical agents without creating anaerobic conditions to the culture of YM1 enhanced the production of biobutanol. When the culture was supplemented with 0.01 g/L potassium ferricyanide, 12.94 g/L biobutanol was obtained. Strain YM1 possess different enzymes that are responsible for oxygen scavenging such as superoxide dismutase (SOD), catalase and NADH/NADPH oxidases. The strain showed novel properties such as producing high concentrations of biobutanol and biohydrogen, generating amylolytic and cellulolytic activities, being capable of utilizing various carbon sources and agro-wastes, resulting into high B:A ratio and being able to grow and produce biobutanol under aerobic condition. The findings imply that C. acetobutylicum YM1 showed novel properties and good potential to be employed in ABE fermentation as a renewable biofuel.,Certification of Master's/Doctoral Thesis" is not available
Pages:	294
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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