Peyman Abdeshahian

Production of butanol by Clostridium saccharoperbutylacetonicum N1-4 from palm kernel cake in acetone–butanol–ethanol fermentation using an empirical model

Palm kernel cake (PKC) was used for biobutanol production by Clostridium saccharoperbutylacetonicum N1-4 in acetone-butanol-ethanol (ABE) fermentation. PKC was subjected to acid hydrolysis pretreatment and hydrolysates released were detoxified by XAD-4 resin. The effect of pH, temperature and inoculum size on butanol production was evaluated using an empirical model. Twenty ABE fermentations were run according to an experimental design. Experimental results revealed that XAD-4 resin removed 50% furfural and 77.42% hydroxymethyl furfural. The analysis of the empirical model showed that linear effect of inoculums size with quadratic effect of pH and inoculum size influenced butanol production at 99% probability level (P<0.01). The optimum conditions for butanol production were pH 6.28, temperature of 28°C and inoculum size of 15.9%. ABE fermentation was carried out under optimum conditions which 0.1g/L butanol was obtained. Butanol production was enhanced by diluting PKC hydrolysate up to 70% in which 3.59g/L butanol was produced.

Enhanced Butanol Production by Clostridium acetobutylicum NCIMB 13357 Grown on Date Fruit as Carbon Source in P2 Medium

The production of biobutanol was studied by the cultivation of Clostridium acetobutylicum NCIMB 13557 in P2 medium including date fruit as the sole substrate. The effect of P2 medium and the effect of different concentrations of date fruit ranging from 10 to 100 g/L on biobutanol production were investigated. Anaerobic batch culture was carried out at 35°C incubation temperature and pH 7.0 ± 0.2 for 72 h. Experimental results showed that the lowest yield of biobutanol and acetone-butanol-ethanol (ABE) was 0.32 and 0.35 gram per gram of carbohydrate consumed (g/g), respectively, when an initial date fruit concentration of 10 g/L was utilized. At this fruit date concentration a biobutanol production value of 1.56 g/L was obtained. On the other hand, the maximum yield of biobutanol (0.48 g/g) and ABE (0.63 g/g) was produced at 50 g/L date fruit concentration with a biobutanol production value as high as 11 g/L. However, when a higher initial date fruit concentration was used, biobutanol and ABE production decreased to reach the yield of 0.22 g/g and 0.35 g/g, respectively, where 100 g/L date fruit was used. Similar results also revealed that 10.03 g/L biobutanol was produced using 100 g/L date fruit.

Repeated Batch Fermentation Biotechnology for the Biosynthesis of Lipid and Gamma-Linolenic Acid by Cunninghamella bainieri 2A1

The biosynthesis of biomedical products including lipid and gamma-linolenic acid (GLA) by Cunninghamella bainieri 2A1 was studied in repeated batch fermentation. Three key process variables, namely, glucose concentration, ammonium tartrate concentration, and harvesting time, were optimized using response surface methodology. Repeated batch fermentation was carried out by the cultivation of Cunninghamella bainieri 2A1 in nitrogen-limited medium with various nitrogen concentration (1–4 g/L) and glucose concentration (20–40 g/L) at three time intervals (12 h, 24 h, and 48 h). Experimental results showed that the highest lipid concentration of 6.2 g/L and the highest GLA concentration of 0.4 g/L were obtained in optimum conditions, where 20.2 g/L glucose, 2.12 g/L ammonium tartrate, and 48 h harvesting time were utilized. Statistical results showed that the interaction between glucose and ammonium tartrate concentration had highly significant effects on lipid and GLA biosynthesis (P < 0.01). Moreover, harvesting time had a significant interaction effect with glucose and ammonium tartrate concentration on lipid production (P < 0.05).

Optimization of Aeration and Agitation Rate for Lipid and Gamma Linolenic Acid Production by Cunninghamella bainieri 2A1 in Submerged Fermentation Using Response Surface Methodology

The locally isolated filamentous fungus Cunninghamella bainieri 2A1 was cultivated in a 5 L bioreactor to produce lipid and gamma-linolenic acid (GLA). The optimization was carried out using response surface methodology based on a central composite design. A statistical model, second-order polynomial model, was adjusted to the experimental data to evaluate the effect of key operating variables, including aeration rate and agitation speed on lipid production. Process analysis showed that linear and quadratic effect of agitation intensity significantly influenced lipid production process (P < 0.01). The quadratic model also indicated that the interaction between aeration rate and agitation speed had a highly significant effect on lipid production (P < 0.01). Experimental results showed that a lipid content of 38.71% was produced in optimum conditions using an airflow rate and agitation speed of 0.32 vvm and 599 rpm, respectively. Similar results revealed that 0.058 (g/g) gamma-linolenic acid was produced in optimum conditions where 1.0 vvm aeration rate and 441.45 rpm agitation rate were used. The regression model confirmed that aeration and agitation were of prime importance for optimum production of lipid in the bioreactor.

Enhanced butanol production by optimization of medium parameters using Clostridium acetobutylicum YM1

A new isolate of the solvent-producing Clostridium acetobutylicum YM1 was used to produce butanol in batch culture fermentation. The effects of glucose concentration, butyric acid addition and C/N ratio were studied conventionally (one-factor-at-a-time). Moreover, the interactions between glucose concentration, butyric acid addition and C/N ratio were further investigated to optimize butanol production using response surface methodology (RSM). A central composite design was applied, and a polynomial regression model with a quadratic term was used to analyze the experimental data using analysis of variance (ANOVA). ANOVA revealed that the model was highly significant (p < 0.0001) and the effects of the glucose and butyric acid concentrations on butanol production were significant. The model validation experiment showed 13.82 g/L butanol was produced under optimum conditions. Scale up fermentation in optimized medium resulted in 17 g/L of butanol and 21.71 g/L of ABE. The experimental data of scale up in 5 L bioreactor and flask scale were fitted to kinetic mathematical models published in the literature to estimate the kinetic parameters of the fermentation. The models used gave the best fit for butanol production, biomass and glucose consumption for both flask scale and bioreactor scale up.