An artificial neural network (ANN) based program coupled with genetic algorithm (GA) was developed on MATLAB platform for predicting the optimized process parameters required for reducing high free fatty acids (FFA) of any vegetable oils for successful transesterification. The developed ANN was a feed forward back propagation network (4-7-13-1) with one input, two hidden and one output layers. The input parameters for the ANN to generalize the pretreatment process were initial acid value of vegetable oil (IAV), methanol-to-oil ratio (M), catalyst concentration (C) and reaction time (T) and the output parameter was final acid value (FAV) of oil. The developed ANN was trained with the experimental data obtained for jatropha, mahua, simaruoba and rice bran oils with acid value more than 14 mg KOH/g-oil. The trained ANN was tested with separate set of data generated from pretreatment of mahua oil using response surface methodology (RSM) based on central composite rotatable design (CCRD) and found to predict the input pretreatment process parameters with low mean square error (MSE) and relative percent deviation (RPD). The well trained ANN synaptic joint weights and threshold values were used by GA to evaluate the fitness (to get FAV of oil less than 2 after pretreatment) of individuals (combinations of M, C and T) for optimization. The optimized process parameters predicted by the developed ANN-GA technique for sunflower oil with IAV 28 ± 1 mg KOH/g-oil were experimentally verified and the FAV was measured to be 2 ± 0.2 mg KOH/g-oil against the predicted value of 2 mg KOH/g-oil. 相似文献
The objective of this research was to produce bioethanol from rice hulls and to evaluate the recovery and potential use of the residue resulting from the enzymatic hydrolysis step before fermentation. Acid pretreatment and enzymatic hydrolysis were studied for saccharification of polysaccharides. Fermentation was conducted for up to 24?h with Saccharomyces cerevisiae yeast. After process optimization, it was possible to produce >7.0?mg?mL?1 of ethanol after only 2?h of reaction. Characterization of the solid residues from the hydrolyzed rice husk and the in natura rice husk showed that these solids have different characteristics and present different adsorption potentials because the residue has higher silica content. The product has potential use in industrial or laboratorial adsorption processes. The results from this study offer support for the potential use of rice husks for bioethanol generation and use the solid residue from hydrolysis for adsorption. 相似文献
Hydrothermal fractionation for micro-algae, Schizocytrium sp., was investigated to separate sugars, lipids, and proteins. This fractionation process produced protein-rich solid cake
and liquid hydrolysates, which contained oligomeric sugars and lipids. Oligomeric sugars and lipids were easily separated
by liquid-liquid separation. Sugars in the separated hydrolyzate were determined to be mainly D-glucose and L-galactose. Fractionation
conditions were optimized by response surface methodology (RSM). Optimal conditions were found to be 115.5 °C of reaction
temperature, 46.7 min of reaction time, and 25% (w/w) of solid loading. The model predicted that maximum oligomeric sugar
yield (based on untreated micro-algae weight), which can be recovered by hydrothermal fractionation at the optimum conditions,
was 19.4 wt% (based on the total biomass weight). Experimental results were in agreement with the model prediction of 16.6
wt%. Production of bioethanol using micro-algae-induced glucan and E. coli KO11 was tested with SSF (simultaneous saccharification and fermentation), which resulted in 11.8 g-ethanol/l was produced from 25.7 g/l of glucose; i.e. the theoretical maximum ethanol yield based on glucan in hydrolyzate was 89.8%. 相似文献
This paper presents two dynamic models for the production of glucose syrups from cassava starch. The models used are based on those proposed by Paolucci et al. [Paolucci, D., Belleville, M.P., Zakhia, N. and Rios G.M., 2000a, Kinetics of cassava starch hydrolysis with Termamyl enzyme, Biotechnol Bioeng, 68(1): 71–77; Paolucci, D., Belleville, M.P., Rios, G.M. and Zakhia, N., 2000b, Kinetics of continuous starch hydrolysis in a membrane reactor, Biochem Eng J, 6(3): 233–238] for the liquefaction stage, and Zanin and Moraes [Zanin, G.M. and Moraes, F.F., 1996, Modelling cassava starch saccharification with amyloglucosidase, Appl Biochem Biotechnol 57–58: 617–625] for the saccharification stage. These models were modified in order to include aspects that were not considered in previously reported studies. Hence, the liquefaction stage can be modeled at different operating temperatures and substrate concentrations; furthermore, this model relates the activity of the enzyme with the temperature. This model of the saccharification stage simulates continuous operation at variable operating temperatures. Additionally, it enables the prediction of reduced glucose production due to the inclusion of a thermal deactivation constant. The improvements to each stage of the models permit a better approximation to real behavior by linking the two models to provide a complete simulation of the process. 相似文献
In organic farming, there is a strong effort to minimize the share of non-renewable resources (e.g. fossil fuels) and use only (preferably on-farm produced) bio-based energy and renewable raw materials, with the aim of achieving sustainable production systems and to become self-sufficient in energy.Throughout our studies, wheat and rye grain was used as raw material in bioethanol production with the purpose of producing in situ enzymes (during germination) for the hydrolysis of starch in the grains and compared with commercial amylase enzyme preparations. Whey permeate was incorporated into the grain in Simultaneous Saccharification and Fermentation (SSF) process to use a cheap nutrient and water source. The ethanol fermentations were completed by 190 h. The fermentation efficiency of germinated and un-germinated grains (without commercial enzymes) was compared with that of commercial enzymes in SSF and furthermore Autoamylolytical Quotient (AAQ) was calculated. On rye 72% yield of the theoretical was achieved by applying commercial enzymes, which decreased only by 10%, when in situ enzymes produced during germination were used alone. The obtained ethanol yields and high (90%) AAQ values showed that rye is a suitable substrate for autoamylolytical processes. According to the low yields (<56%) and AAQs values for all examined wheat samples the results implied that the tested sorts of wheat grains were no efficient for use in autoamylolytical processes. 相似文献
In biodiesel production, to use low cost feedstock such as rendered animal fats may reduce the biodiesel cost. One of the low cost animal fats is the chicken fat for biodiesel production. It is extracted from feather meal which is prepared from chicken wastes such as chicken feathers, blood, offal and trims after rendering process. However, chicken fats often contain significant amounts of FFA which cannot be converted to biodiesel using an alkaline catalyst due to the formation of soap. Therefore, the FFA level should be reduced to desired level (below 1%) by using acid catalyst before transesterification. For this aim, sulfuric, hydrochloric and sulfamic (amidosulfonic) acids were used for pretreatment reactions and the variables affecting the FFA level including alcohol molar ratio, acid catalyst amount and reaction time were investigated by using the chicken fat with 13.45% FFA. The optimum pretreatment condition was found to be 20% sulfuric acid and 40:1 methanol molar ratio based on the amount of FFA in the chicken fat for 80 min at 60 °C. After transesterification, the methyl ester yield was 87.4% and the measured fuel properties of the chicken fat methyl ester met EN 14214 and ASTM D6751 biodiesel specifications. 相似文献
Biomass feedstocks available decentrally will be more commodious for localized biorefinery approach than the exhaustive large scale and centralized plants driven by cost intensive technology. Lichen is present in a wide range of habitats in a distributed manner. A maximum hydrolysis of 73%-76% for lichenan from Cetraria islandica, Usnea barbata and Parmelia sp. were obtained in 24 h using lichenase from an alkalothermophilic Thermomonospora sp. wherein the hydrolysis was 100% with commercial enzyme Accellerase™1000. The synergistic role of β-glucosidase in lichenan hydrolysis was demonstrated by the exogenous addition of β-glucosidase to Thermomonospora lichenase which resulted in complete hydrolysis. The hydrolysates of lichenan obtained using Accellerase or a cocktail of Thermomonospora lichenase and β-glucosidase when fermented with free cells of Saccharomyces at 40 °C produced an ethanol yield of 0.45 g/g-0.48 g/g with theoretical conversion efficiencies of 93%-96%. The Ca-alginate immobilized yeast cells were reused eight times at 40 °C with 100% fermentation efficiency. 相似文献
The production of bio-hydrogen from raw cassava starch via a mixed-culture dark fermentation process was investigated. The production yield of H2 was optimized by adjusting the substrate concentration and the microorganism mixture ratio. A maximum H2 yield of 1.72 mol H2/mol glucose was obtained with a cassava starch concentration of 10 g/L to give a 90% utilization rate. The kinetics of the substrate utilization and of the generation of both hydrogen and volatile fatty acids were also investigated. The substrate utilization follows pseudo first order reaction kinetics, whereas the production of both H2 and the VFAs correlate with the Gompertz equation. These results show that cassava is a good candidate for the production of biohydrogen.