Substrate For Biodiesel Production Research Articles

Advances in metabolic engineering of cyanobacteria for production of biofuels

Current trends in fossil fuel use, having a direct impact on the global carbon cycle, could potentially be mitigated by adopting the use of biofuels with sustainable features. While bioethanol is currently being used as a major biofuel, especially for transportation worldwide, it is hygroscopic and contains less energy. Therefore, the prospect of biofuels has now shifted to higher alcohols, alkanes, and other molecules that have similar properties to existing gasoline and diesel fuels. Microalgae and cyanobacteria are aquatic photosynthetic microorganisms that can convert CO2 and water into carbon-rich lipids, a substrate for biodiesel production, more efficiently than the agricultural oleaginous crops, making them a superior option to traditional oil-seed crops. Cyanobacteria are gram-negative photosynthetic bacteria that have instrumental roles in global biological carbon sequestration, oxygen evolution, and nitrogen fixation. Furthermore, cyanobacteria have established genetic backgrounds, flexibility in genetic manipulation, and tolerance to the introduction of foreign genes. Metabolic engineering strategies in these photosynthetic hosts have resulted in the conception of cell factories capable of one-step synthesis of biofuel molecules from CO2, light, and water. Two freshwater cyanobacteria species, Synechocystis sp. PCC 6803 (Synechocystis 6803) and Synechococcus elongatus sp. PCC 7492 (Synechococcus 7492), and marine Synechococcus sp. PCC 7002 (Synechococcus 7002) are among the highly studied cyanobacteria for the production of biofuels. Here, we reviewed the recent progress in metabolic engineering and synthetic biology approaches in cyanobacteria for the synthesis of various biofuel molecules, ranging from alcohols to biodiesels and terpenes or terpenoids.

Optimization of process parameters of the growth of Chlorella vulgaris for the production of biodiesel feedstock (microbial lipid) using sago wastewater as substrate

The present study investigated the growth of microalgae Chlorella vulgaris in sago wastewater as a substrate for biodiesel production. The optimum conditions, namely pH, temperature, carbon dioxide (CO2), and carbon/nitrogen ratio (C/N), were studied. The central composite design (CCD) was developed using four coded factors for the experimental trials. The maximum algal biomass and lipid production was obtained as 26.50 and 14.10 g/L respectively at an optimum condition of pH of 8, the temperature of 35 °C, CO2 of 1%, and C/N ratio of 80. Different growth kinetic models, namely the Malthus equation, Tessier equation, Lineweaver-Burk plot, and logistic equation, were studied. The Lineweaver-Burk model fits the best modeling equation with a maximum specific growth rate of 0.062 h−1 and a Ks value of 0.86 g/L. The fatty acid profile of Chlorella vulgaris confirmed the presence of palmitic and linolenic acid to a percentage of 45.2 and 32.2%, respectively.

Utilization of pomegranate waste-peel as a novel substrate for biodiesel production by Bacillus cereus (MF908505)

The continuous rising demands and fluctuations in the prices of fossil fuels warrant searching for an alternative renewable energy source to manage the energy needs.

Utilization of coconut meal, a waste product of milk processing, as a novel substrate for biodiesel and bioethanol production

Coconut meal, a waste product left after coconut milk processing, was collected and utilized as raw substrate for biofuel production. Biofuel production was produced via two steps. Biodiesel was first produced from coconut meal’s oil. Afterward, bioethanol was produced by Saccharomyces cerevisiae, using coconut waste after oil extraction as the sole carbon source. In this study, oil extraction methods, including chill and centrifugation, fermentation, and dry processing, were determined. The highest yield was obtained from dry processing (42.2%). The moisture and free fatty acid content of waste coconut oil (WCO) was 0.1% and 0.3–0.5%, respectively. Therefore, WCO was favourable to use as a substrate for biodiesel production. The highest biodiesel yield (98.1%) was observed from an alkali catalyst. Fuel properties of biodiesel from WCO met the biodiesel standard of the USA (ASTM D6751-07) and Europe (EN 14214). Thereafter, solid coconut waste (SCW) after oil extraction was collected and pre-treated using 50% NaOH. Cellulose content (62.1%) significantly increased after alkali pre-treatment. Thereafter, pre-treated SCW was hydrolysed with cellulase derived from Trichoderma viride and Aspergillus niger. Glucose (20.3 g/L) was a major end product in enzymatic hydrolysate. SCW hydrolysate was utilized as fermentation medium without nutritional supplementation. The production of ethanol constantly increased and reached 8.5 g/L (equivalent to 82.4% of theoretical yield) after 60 h.

Single cell oil and its application for biodiesel production

Abstract Micro-organisms such as bacteria (Bacillus), yeasts, molds and algae that can accumulate lipid more than 20% of their biomass are called oleaginous microorganisms. Microbial lipid has similarity with the plant’s oil in type and composition. Lipid accumulation in oleaginous micro-organisms occurs with starvation of the cell in nitrogen or other nutrients except carbon, such as phosphorus, zinc, iron and magnesium. Lipid body’s formation starts at the end of logarithmic phase and continues during station phase until carbon source begins to reduce. Microbial oil has potential for application in biodiesel production because of their similarity to plant’s oil in composition and structure of fatty acids. The main effort is biodiesel production from low cost substrats. At the current time rice straw and corn stalk are burned in farms and increase air pollution, affect on public health and waste energy sources. If biodiesel can be produced from plant and forestry residues, have environmental benefits beyond economical benefits. Generally there are three steps for production of microbial oil and ultimately use of this oil as the substrate for biodiesel production and other products. These steps are: 1- screening of oleaginous micro-organisms with high potential of lipid production. 2- increasing of lipid content by optimizing environmental parameters and also using mutation. 3- application of byproducts for lipid production. This review is covering different researches about single cell oil production by oleaginous yeasts, different parameters which affect optimized production and also potential of this oil for biodiesel production.

Microbial lipid production from SPORL-pretreated Douglas fir by Mortierella isabellina

The solid substrate and spent liquor obtained after SPORL pretreatment of Douglas fir residues were evaluated as substrates for the production of intracellular microbial lipid by Mortierella isabellina NRRL 1757. The production of lipid was investigated in a batch fermentation using different strategies viz. separate hydrolysis and fermentation, quasi-simultaneous saccharification and fermentation (Q-SSF), and whole slurry (solid substrate and spent liquor) saccharification and fermentation. The maximum lipid yield (0.21g/g sugar) was obtained with Q-SSF of the solid substrate. Nutrient supplementation was not necessary for lipid production from SPORL-pretreated Douglas fir. Detoxification of SPORL spent liquor with lime did remove the inhibitors and improved the fermentation for lipid production. The lipid produced had a similar fatty acid compositional profile to those of vegetable oil, suggesting that it could have potential as a substrate for biodiesel production.

Esterification of Oleic Acid and Bioalcohols Using Immobilized Lipase

Biodiesel has been receiving significant attention as a renewable and nonpolluting fuel. In this study, oleic acid and bioalcohols (ethanol and butanol) were used as substrates for biodiesel production. The reactions were performed in a solvent-free system using immobilized lipase (Novozym 435) as biocatalyst in a batch esterification process. The optimal conditions were 45°C, oleic acid to alcohol molar ratio of 1:2, Novozym 435 loading at 5% based on oleic acid weight and 250 rpm, in which the free fatty acid (FFA) conversion at 91.0% was obtained after 12 hours of the reaction.

Biodiesel synthesis by a one-step method in a genetically engineered Escherichia coli using rice straw hydrolysate and restaurant oil wastes as raw materials

To reduce the cost of biodiesel, the utilization of rice straw hydrolysate and restaurant oil wastes as the substrates for biodiesel production in a recombinant strain by a one-step method was investigated. A recombinant Escherichia coli pET28a (+)-PAW, which encodes enzymes for the ethanol pathway and acyltransferase, was constructed. Fermentation results in Luria-Bertani medium revealed that xylose was favourable for fatty acid ethyl esters (FAEEs) production (2.79 g l(-1) ) by E. coli pET28a (+)-PAW. When rice straw hydrolysate and restaurant oil wastes were utilized as the monosaccharide substituent and the fatty acids substituent, 0.27 g l(-1) FAEEs and 0.249 g l(-1) FAEEs were obtained, respectively. 1.27 g l(-1) FAEEs was obtained in the restaurant oil wastes medium supplemented by 2% sodium oleate. The fermentation results indicated that the strain was effective in biodiesel production. The rice straw hydrolysate and restaurant oil wastes could be utilized by E. coli as the substrates for FAEE production. This novel exploration might pave the way for biodiesel production from waste materials by genetically engineered microorganism.

Comparative analysis for the production of fatty acid alkyl esterase using whole cell biocatalyst and purified enzyme from Rhizopus oryzae on waste cooking oil (sunflower oil)

The petroleum fuel is nearing the line of extinction. Recent research and technology have provided promising outcomes to rely on biodiesel as the alternative and conventional source of fuel. The use of renewable source – vegetable oil constitutes the main stream of research. In this preliminary study, Waste Cooking Oil (WCO) was used as the substrate for biodiesel production. Lipase enzyme producing fungi Rhizopus oryzae 262 and commercially available pure lipase enzyme were used for comparative study in the production of Fatty Acid Alkyl Esters (FAAE). The whole cell (RO 262) and pure lipase enzyme (PE) were immobilized using calcium alginate beads. Calcium alginate was prepared by optimizing with different molar ratios of calcium chloride and different per cent sodium alginate. Entrapment immobilization was done for whole cell biocatalyst (WCB). PE was also immobilized by entrapment for the transesterification reaction. Seven different solvents – methanol, ethanol, n-propanol, n-butanol, iso-propanol, iso-butanol and iso-amyl alcohol were used as the acyl acceptors. The reaction parameters like temperature (30°C), molar ratio (1:3 – oil:solvent), reaction time (24h), and amount of enzyme (10% mass ratio to oil) were also optimized for methanol alone. The same parameters were adopted for the other acyl acceptors too. Among the different acyl acceptors – methanol, whose reaction parameters were optimized showed maximum conversion of triglycerides to FAAE-94% with PE and 84% with WCB. On the whole, PE showed better catalytic converting ability with all the acyl acceptor compared to WCB. Gas chromatography analysis (GC) was done to determine the fatty acid composition of WCO (sunflower oil) and FAAE production with different acyl acceptors.

Chemical Extraction and Property Analyses of Marula Nut Oil for Biodiesel Production

To identify and develop alternative and renewable sources of fuel for the transport sector is a present chal- lenge for engineers and researchers. This work was carried out to assess yield of marula (Sclero carrya/birrea) nut and chemical properties of crude marula nut oil for biodiesel production in Botswana. Chemical extrac- tion of marula oil was done to establish actual oil content by use of hexane/iso-propyl alcohol solvent in a soxhlet set up. Distillation was carried out on a Rotavapor system prior to oil purging using nitrogen gas. The results indicated that marula nuts have about 58.6% oil content. Characterisation of the extracted crude oil was carried out to determine its chemical composition using the Waters GCT Premier Time of Flight (TOF) Mass Spectrometer (MS) coupled to the Agilent 6890 N Gas Chromatography (GC) system. Ethyl oleate (ethyl ester) was found to be the dominant fatty acid. Trans-Oleic acid was also abundant but could not be quantified because it was not found in the standard mixture. Crude marula oil was also found to have an ester content of 93.7%, acid value of 1.4 mg KOH/g, and free fatty acid content of 0.7%. These results are mar- ginally out of specifications for biodiesel by international standards, implying that crude marula oil is a po- tential substrate for biodiesel production.