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Title:	Enhancement of lipid and gamma-linolenic acid production by Cunninghamella bainieri 2A1 using repeated batch culture
Authors:	Marjan Ganjali Dashti (P46898)
Supervisor:	Aidil Abdul Hamid, Prof. Madya Dr.
Keywords:	Dissertations, Academic -- Malaysia Lipids -- Biotechnology Oils and fats -- Biotechnology Fatty acids -- Analysis Universiti Kebangsaan Malaysia -- Dissertations
Issue Date:	12-Sep-2012
Description:	Enhancement of lipid and γ-linolenic acid (GLA) production from locally isolated fungi Cunninghamella bainieri.2A1 was investigated to maximize the effects of different agitation rates (50, 120, 180, 250 and 320 rpm) in batch culture. Different harvesting time (12, 24 and 48 h) and harvesting volume (60, 70, 80 and 90%) in repeated batch culture was maximized. Different glucose (20, 30 and 40 g/L) and nitrogen concentration (1, 2.5 and 4 g/L) and harvesting time (12, 24 and 48 h) in repeated batch culture using response surface methodology. In the first stage, batch cultivation was carried out using 500 mL Erlenmeyer flask containing 200 mL of nitrogen limited medium. Cultures were incubated at 30 ◦C at different agitation rates for 120 h. Experimental results revealed that the highest biomass concentration (10.6 g/L) and lipid concentration (3.1 g/L) were obtained at an agitation rate of 320 rpm at 96 h, however maximum GLA production was achieved at the agitation rate of 250 rpm. The maximum lipid percentage (34%) was achieved at 96 h with an agitation rate of 250 rpm. This study showed that 250 rpm can be designated to produce best results for GLA, lipid and biomass productivity and efficiency (Yp/s ,Yp/x and Yx/s) within 24 h. Repeated batch culture was studied based on harvesting time and harvesting volume. Different volumes of batch culture (20, 40, 60 and 80 mL) were transferred to fresh medium (180, 160, 140,120 mL) replacing an equal volume of harvested culture with the repetition involving three time intervals of 12 h, 24 h and 48 h. Results showed that the highest biomass concentration, lipid concentration and lipid percentage were obtained (11 g/L, 3.3 g/L and 30%, respectively) within the 48 h harvesting time with 160 mL harvesting volume in repeated batch culture. The highest amount of GLA concentration (0.23 g/L) was obtained after 192 h at optimum condition (48 h harvesting time and 80% harvesting volume). It was concluded that repeated batch culture showed a higher performance than batch culture. The simultaneous effects of three independent variables, namely glucose concentration, nitrogen concentration and harvesting time were evaluated by response surface methodology on the basis of central composite face-centered design using Design- Expert software (version 6.0.6 Stat-Ease, Inc.). Eighteen trials were conducted in which Cunninghamella bainieri 2A1 was cultivated in repeated batch method for four days. The highest biomass production (21.5 g/L), lipid production (6.1 g/L), lipid content (35.7%) and GLA production (0.45 g/L) were recorded. The peak biomass and lipid production were obtained when the repeated batch process was operated at 30 g/L glucose concentration, 2.5 g/L nitrogen concentration and 48 h harvesting time. The maximum lipid content and GLA production was recorded at glucose concentration of 20 g/L and nitrogen concentration 1 g/L. Time of harvesting did not give any effect. Hence, glucose concentration 20 g/L, nitrogen concentration 2 g/L and harvesting time 48 h were concluded as the optimum parameters for the optimum growth of Cunninghamella bainieri 2A1 and also for the production of lipid and GLA in repeated batch culture.,Certification of Master's / Doctorial Thesis" is not available
Pages:	124
Call Number:	QP752.L515D347 2012 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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