Biomedical and Biotechnology,
F. Amiri; A. R. Habibi; M. M. Nourouzpour
Abstract
The application of the agro-industrial waste as the feedstock helps to decrease the operational cost of the fermentation process. Soapstock is a by-product of the vegetable oil refinery and enriched with fatty acids including linoleic acid which has a high potential application in the production of biosurfactants. ...
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The application of the agro-industrial waste as the feedstock helps to decrease the operational cost of the fermentation process. Soapstock is a by-product of the vegetable oil refinery and enriched with fatty acids including linoleic acid which has a high potential application in the production of biosurfactants. In this study, a dual carbon source system, including glucose and free fatty acids recovered from a sunflower soapstock, was used for the synthesis of sophorolipid (SL) by Candida catenulata. The production of SL showed a major dependence on the initial carbon sources and the concentration of urea as the nitrogen source. The inoculum size was another influential factor in the fermentation process. The optimization of these factors was evaluated by the one-factor-at-a-time and the response surface methodology (RSM). The one-factor-at-a-time approach gained the best SL productivity (Y1) of about 52.08 mg L-1 h-1 and SL-to-biomass yield (Y2) of 712 mgSL gcell-1 at the inoculum size of 4% vv-1, 100 g L-1 of glucose, 80 g L-1 of soapstock, and 7.5 g L-1 of urea. While the RSM, due to considering interactional effects of the factors, obtained the best condition at 100 g L-1 of glucose, 100 g L-1 of the soapstock, 9.3 g L-1 of urea, and an inoculum size of 6.3% vv-1 with the Y1 and Y1 values of about 58.10 mg L-1 h-1 and 713 mgSL gcell-1, respectively. The characterization of the produced SLs by the GC-MS analysis indicated that a di-acylated C16:1 acidic sophorolipid with an m/z ratio of 679 amu was the main product.
Energy
Abbas Mohammadi; Barat Ghobadian
Abstract
A continuous process was designed and optimized at a conceptual stage for the biodiesel production from waste vegetable oils. Unlike previous studies, the process was optimized taking into account the technical and economic considerations, simultaneously, to find the optimum operating conditions fort ...
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A continuous process was designed and optimized at a conceptual stage for the biodiesel production from waste vegetable oils. Unlike previous studies, the process was optimized taking into account the technical and economic considerations, simultaneously, to find the optimum operating conditions fort he commercial scale productions. The effect of major variables on the yield of the process was studied by modeling esterification and transesterification reactors. The mole fraction of free fatty acids (FFAs) in the feedstock, production rate, conversion and molar ratio of the reactants in both reactors were chosen as major variables. By considering the economic potential as the objective function of the process optimization, the optimum mole fraction of FFA was obtained as about 0.50 (24 wt %). Also, the optimum values of the conversion and molar ratio of the reactants in the esterification and transesterification reactors were found as 82-89 % (depending on the different production rates), 11:1 and 96 %, 8:1 respectively. It was found that the economic potential increases linearly as the production rate increases. Therefore, the production rate should be set at its maximum possible practical value. The break-even point at the optimum values of these variables, as mentioned above, occurs at the production rate of 157 ton/yr.