The General Applicability of in Situ Transesterification for the Production of Fatty Acid Esters from a Variety of Feedstocks

Journal of the American Oil Chemists' Society (Impact Factor: 1.54). 09/2007; 84(10). DOI: 10.1007/s11746-007-1119-4
Source: OAI


We previously described a method for fatty acid methyl ester (FAME) production wherein acylglycerol transesterification was achieved by reacting flaked full fat soybeans with alkaline methanol to create a product that met ASTM specifications for biodiesel. In the present work we explore the general applicability of this approach, termed in situ transesterification, to feedstocks other than soybeans. Materials investigated were distillers dried grains with solubles (DDGS), which is a co-product of the production of ethanol from corn, and meat and bone meal (MBM), a product of animal rendering. For both feedstocks, reaction conditions giving maximum lipid transesterification were predicted by statistical experimental design and response surface regression analysis, and then verified experimentally. Successful transesterification was achieved at ambient pressure and 35 °C. For DDGS, partial drying markedly reduced the methanol requirement to achieve a high degree (91.1% of maximum theoretical) of transesterification. Elevated reaction temperatures (to 55 °C was explored) caused little or no shortening of the time to completion. Protein was not removed from the DDGS during this treatment. For MBM, drying was not required to achieve a high degree (93.3%) of transesterification. The remaining meal retained approximately 90% of the protein originally present. Coupled with the previous work with soybeans, the data presented here indicate that in situ transesterification is generally applicable to lipid-bearing materials, which could substantially increase the supply of biodiesel.

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Available from: Karen Michele Wagner, Mar 12, 2014
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    • "Normally, high acyl acceptor volume for increasing lipids diffusion and FAME yield has been used in biomass transesterification (Ehimen et al., 2010). Acyl acceptor excess plays also a role as extraction solvent, improving the contact between catalyst and biomass, altering the permeability of the solid substrate (Haas et al., 2007). Besides, acyl acceptor excess is responsible for breaking linkages between glycerin and fatty acids during the reaction (Hidalgo et al., 2013). "
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    ABSTRACT: Direct transesterification of Botryococcus braunii with continuous acyl acceptor reflux was evaluated. This method combines in one step lipid extraction and esterification/transesterification. Fatty acid methyl esters (FAME) synthesis by direct conversion of microalgal biomass was carried out using sulfuric acid as catalyst and methanol as acyl acceptor. In this system, once lipids are extracted, they are contacted with the catalyst and methanol reaching 82%wt of FAME yield. To optimize the reaction conditions, a factorial design using surface response methodology was applied. The effects of catalyst concentration and co-solvent concentration were studied. Hexane was used as co-solvent for increasing lipid extraction performance. The incorporation of hexane in the reaction provoked an increase in FAME yield from 82% (pure methanol) to 95% when a 47%v/v of hexane was incorporated in the reaction. However, the selectivity towards non-saponifiable lipids such as sterols was increased, negatively affecting biodiesel quality. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Full-text · Article · Jan 2015 · Bioresource Technology
    • "Optimal commercial lipid extraction processes should not only consider total lipid yields and minimization of co-extraction of impurities such as pigments, but should also aim to preferentially extract specific fatty acids that provide optimal biodiesel characteristics [28] [29] [30]. Traditional hexane solvent extraction and in-situ transesterification [31] methods for biodiesel production may not be suitable for many microalgae because of the presence of water and cell wall barriers [32] [33]. The high levels of fat-soluble pigments in microalgae further complicate selective extraction of fatty acids and purification of the biofuel [34]. "
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    ABSTRACT: Commercially viable carbon–neutral biodiesel production from microalgae has potential for replacing depleting petroleum diesel. The process of biodiesel production from microalgae involves harvesting, drying and extraction of lipids which are energy- and cost-intensive processes. The development of effective large-scale lipid extraction processes which overcome the complexity of microalgae cell structure is considered one of the most vital requirements for commercial production. Thus the aim of this work was to investigate suitable extraction methods with optimised conditions to progress opportunities for sustainable microalgal biodiesel production. In this study, the green microalgal species consortium, Tarong polyculture was used to investigate lipid extraction with hexane (solvent) under high pressure and variable temperature and biomass moisture conditions using an Accelerated Solvent Extraction (ASE) method. The performance of high pressure solvent extraction was examined over a range of different process and sample conditions (dry biomass to water ratios (DBWRs): 100%, 75%, 50% and 25% and temperatures from 70 to 120 °C, process time 5–15 min). Maximum total lipid yields were achieved at 50% and 75% sample dryness at temperatures of 90–120 °C. We show that individual fatty acids (Palmitic acid C16:0; Stearic acid C18:0; Oleic acid C18:1; Linolenic acid C18:3) extraction optima are influenced by temperature and sample dryness, consequently affecting microalgal biodiesel quality parameters. Higher heating values and kinematic viscosity were compliant with biodiesel quality standards under all extraction conditions used. Our results indicate that biodiesel quality can be positively manipulated by selecting process extraction conditions that favour extraction of saturated and mono-unsaturated fatty acids over optimal extraction conditions for polyunsaturated fatty acids, yielding positive effects on cetane number and iodine values. Exceeding biodiesel standards for these two parameters opens blending opportunities with biodiesels that fall outside the minimal cetane and maximal iodine values.
    No preview · Article · Dec 2014 · Energy Conversion and Management
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    • "The alternate use of the one-step in situ transesterification method for biodiesel production has been discussed to potentially lead to the reduction of the energetic, raw material, and economic process requirements when compared to the use of the conventional oil extraction and transesterification process [13]. "
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    ABSTRACT: A research on production of biodiesel from lipid of phytoplankton Porphyridium cruentum through ultrasonic method has been done. In this research, we carried out a series of phytoplankton cultures to determine the optimum time of growth and biodiesel synthesis process from phytoplankton lipids. Process of biodiesel synthesis consists of two steps, that is, isolation of phytoplankton lipids and biodiesel synthesis from those lipids. Oil isolation process was carried out by ultrasonic extraction method using ethanol 96%, while biodiesel synthesis was carried out by transesterification reaction using methanol and KOH catalyst under sonication. Weight of biodiesel yield per biomass Porphyridium cruentum is 40,27%. Characterization of biodiesel was well carried out in terms of physical properties which are density and viscosity and chemical properties which are FFA content, saponification value, and iodine value. These values meet the American Society for Testing and Materials (ASTM D6751) standard levels, except for the density value which was 0.9461 g·cm−3 and the FFA content which was 4.6671%.
    Full-text · Article · Mar 2014
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