Biological Methods in Biodiesel Production and Their Environmental Impact (original) (raw)

Biotechnological processes for biodiesel production using alternative oils

Applied Microbiology and Biotechnology, 2010

As biodiesel (fatty acid methyl ester (FAME)) is mainly produced from edible vegetable oils, crop soils are used for its production, increasing deforestation and producing a fuel more expensive than diesel. The use of waste lipids such as waste frying oils, waste fats, and soapstock has been proposed as low-cost alternative feedstocks. Non-edible oils such as jatropha, pongamia, and rubber seed oil are also economically attractive. In addition, microalgae, bacteria, yeast, and fungi with 20% or higher lipid content are oleaginous microorganisms known as single cell oil and have been proposed as feedstocks for FAME production. Alternative feedstocks are characterized by their elevated acid value due to the high level of free fatty acid (FFA) content, causing undesirable saponification reactions when an alkaline catalyst is used in the transesterification reaction. The production of soap consumes the conventional catalyst, diminishing FAME production yield and simultaneously preventing the effective separation of the produced FAME from the glycerin phase. These problems could be solved using biological catalysts, such as lipases or whole-cell catalysts, avoiding soap production as the FFAs are esterified to FAME. In addition, by-product glycerol can be easily recovered, and the purification of FAME is simplified using biological catalysts.

Production of Biodiesel by Enzymatic Transesterification: Review

American Journal of …, 2010

Waste sardine oil, a byproduct of fish industry, was employed as a low cost feedstock for biodiesel production. It has relatively high free fatty acid (FFA) content (32 mg KOH/g of oil). Lipase enzyme immobilized on activated carbon was used as the catalyst for the transesterification reaction. Process variables viz. reaction temperature, water content and oil to methanol molar ratio were optimized. Optimum methanol to oil molar ratio, water content and temperature were found to be 9:1, 10 v/v% and 30°C respectively. Reusability of immobilized lipase was studied and it was found after 5 cycles of reuse there was about 13% drop in FAME yield. Engine performance of the produced biodiesel was studied in a Variable Compression Engine and the results confirm that waste sardine oil is a potential alternate and low-cost feedstock for biodiesel production.

REVIEW Biodiesel Fuel Production by Transesterification of Oils

Biodiesel (fatty acid methyl esters), which is derived from triglycerides by transesterification with methanol, has attracted considerable attention during the past decade as a renewable, biodegradable , and nontoxic fuel. Several processes for biodiesel fuel production have been developed, among which transesterification using alkali-catalysis gives high levels of conversion of triglycer-ides to their corresponding methyl esters in short reaction times. This process has therefore been widely utilized for biodiesel fuel production in a number of countries. Recently, enzymatic trans-esterification using lipase has become more attractive for biodiesel fuel production, since the glyc-erol produced as a by-product can easily be recovered and the purification of fatty methyl esters is simple to accomplish. The main hurdle to the commercialization of this system is the cost of lipase production. As a means of reducing the cost, the use of whole cell biocatalysts immobilized within biomass support particles is significantly advantageous since immobilization can be achieved spontaneously during batch cultivation, and in addition, no purification is necessary. The lipase production cost can be further lowered using genetic engineering technology, such as by developing lipases with high levels of expression and/or stability towards methanol. Hence, whole cell bio-catalysts appear to have great potential for industrial application.

Biodiesel fuel production by transesterification of oils

Journal of bioscience and bioengineering, 2001

Biodiesel (fatty acid methyl esters), which is derived from triglycerides by transesterification with methanol, has attracted considerable attention during the past decade as a renewable, biodegradable, and nontoxic fuel. Several processes for biodiesel fuel production have been developed, among which transesterification using alkali-catalysis gives high levels of conversion of triglycerides to their corresponding methyl esters in short reaction times. This process has therefore been widely utilized for biodiesel fuel production in a number of countries. Recently, enzymatic transesterification using lipase has become more attractive for biodiesel fuel production, since the glycerol produced as a by-product can easily be recovered and the purification of fatty methyl esters is simple to accomplish. The main hurdle to the commercialization of this system is the cost of lipase production. As a means of reducing the cost, the use of whole cell biocatalysts immobilized within biomass support particles is significantly advantageous since immobilization can be achieved spontaneously during batch cultivation, and in addition, no purification is necessary. The lipase production cost can be further lowered using genetic engineering technology, such as by developing lipases with high levels of expression and/or stability towards methanol. Hence, whole cell biocatalysts appear to have great potential for industrial application.

FEATURES OF BIODIESEL PRODUCTION FROM WASTE OILS AND TECHNICAL ANIMAL FATS

Biodiesel (fatty acid methyl esters), which is derived from triglycerides by transesterification with methanol, has attracted considerable attention during the past decade as a renewable, biodegradable, and nontoxic fuel. Several processes for biodiesel fuel production have been developed, among which transesterification using alkali-catalysis gives high levels of conversion of triglycerides to their corresponding methyl esters in short reaction times. This process has therefore been widely utilized for biodiesel fuel production in a number of countries. The characteristics of biodiesel have made the pursuit of high quality biodiesel production attractive. Utilization of waste cooking oil is a key component in reducing biodiesel production costs up to 60–90%. Researchers have used various types of homogeneous and heterogeneous catalyzed transesterification reaction for biodiesel production. The main hurdle to the commercialization of this system is the cost of lipase production. As a means of reducing the cost, the use of whole cell biocatalysts immobilized within biomass support particles is significantly advantageous since immobilization can be achieved spontaneously during batch cultivation, and in addition, no purification is necessary. Consequently, the study of the transformation of waste of vegetable and animal fats is promising and has great potential for industrial application.

A review on catalytic biodiesel production

The industrialization of societies and as the result, the increase of demand for fuel in the world and speculations on the reduction of fossil fuels and on the other hand, the issue of world health emphasizes on the necessity of substituting renewable and clean energy, so biodiesel as the best substitute for diesel fuels is common. In general, three ways are used to produce biodiesel including pyrolysis, micro-emulsification and transesterification among which transesterification is known as the most usual and common way. The catalysts used in transesterification are divided into three groups of acidic, alkaline and enzymatic catalysts in which the acidic and alkaline catalysts in turn divide into two groups of heterogeneous and homogeneous. The Transesterification reaction using acidic catalysts involves more time for the reaction and high cost. The alkaline catalysts produce an appropriate amount of product in moderate operational conditions and show a better performance in comparison with the other catalysts. These catalysts have a limitation in use for raw material containing high free fatty acids. The way of using Lipase catalysts is the most viable method that can be applied, however it requires high costs. Given today's high total cost as the main obstacle for producing biodiesel, using animal fats and waste oils as raw material and using the heterogeneous catalysts and preferably renewable ones is suggested so as to reduce the total cost.

Recent advances in biodiesel production: Challenges and solutions

Science of The Total Environment, 2021

Mono alkyl fatty acid ester or methyl ethyl esters (biodiesel) are the promising alternative for fossil fuel or petroleum derived diesel with similar properties and could reduce the carbon footprint and the green house gas emissions. Biodiesel can be produced from renewable and sustainable feedstocks like plant derived oils, and it is biodegradable and non-toxic to the ecosystem. The process for the biodiesel production is either through tradition chemical catalysts (Acid or Alkali Transesterification) or enzyme mediated transesterification, but as enzymes are natural catalysts with environmentally friendly working conditions, the process with enzymes are proposed to overcome the drawbacks of chemical synthesis. At present 95% of the biodiesel production is contributed by edible oils worldwide whereas recycled oils and animal fats contribute 10% and 6% respectively. Although every process has its own limitations, the enzyme efficiency, resistance to alcohols, and recovery rate are the crucial factors to be addressed. Without any benefit of doubt, production of biodiesel using renewable feedstocks and enzymes as the catalysts could be recommended for the commercial purpose, but further research on improving the efficiency could be an advantage.