Economics Of Biodiesel Production Research Articles

Screening high oleaginous Chlorella strains from different climate zones

In outdoor cultivation, screening strains adapted to a wide temperature range or suitable strains for different environmental temperatures is of great importance. In this study, triacylglycerol (TAG) content of 23 oil-producing Chlorella strains from different climate zones were analyzed by thin layer chromatography. Four selected Chlorella strains (NJ-18, NJ-7, NMX35N and NMX139N) with rather high TAG content had higher total lipid content compared with Chlorella vulgaris SAG 211-11b. In particular, NJ-18 displayed the highest TAG productivity among the four high oil-producing Chlorella strains. Accumulation of TAGs in strain NMX35N changed a little from 30 to 40°C, showing a desirable characteristic of accumulating TAGs at high temperatures. Our results demonstrated that NJ-18 and NMX35N had suitable fatty acid profiles and good adaption to low and high temperatures respectively. Therefore, cultivation of the two Chlorella strains together might be a good option for economic biodiesel production during the whole seasons of the year.

Production of extracellular fatty acid using engineered Escherichia coli.

BackgroundAs an alternative for economic biodiesel production, the microbial production of extracellular fatty acid from renewable resources is receiving more concerns recently, since the separation of fatty acid from microorganism cells is normally involved in a series of energy-intensive steps. Many attempts have been made to construct fatty acid producing strains by targeting genes in the fatty acid biosynthetic pathway, while few studies focused on the cultivation process and the mass transfer kinetics.ResultsIn this study, both strain improvements and cultivation process strategies were applied to increase extracellular fatty acid production by engineered Escherichia coli. Our results showed overexpressing ‘TesA and the deletion of fadL in E. coli BL21 (DE3) improved extracellular fatty acid production, while deletion of fadD didn’t strengthen the extracellular fatty acid production for an undetermined mechanism. Moreover, the cultivation process controls contributed greatly to extracellular fatty acid production with respect to titer, cell growth and productivity by adjusting the temperature, adding ampicillin and employing on-line extraction. Under optimal conditions, the E. coli strain (pACY-‘tesA-ΔfadL) produced 4.8 g L−1 extracellular fatty acid, with the specific productivity of 0.02 g h−1 g−1dry cell mass, and the yield of 4.4% on glucose, while the ratios of cell-associated fatty acid versus extracellular fatty acid were kept below 0.5 after 15 h of cultivation. The fatty acids included C12:1, C12:0, C14:1, C14:0, C16:1, C16:0, C18:1, C18:0. The composition was dominated by C14 and C16 saturated and unsaturated fatty acids. Using the strain pACY-‘tesA, similar results appeared under the same culture conditions and the titer was also much higher than that ever reported previously, which suggested that the supposedly superior strain did not necessarily perform best for the efficient production of desired product. The strain pACY-‘tesA could also be chosen as the original strain for the next genetic manipulations.ConclusionsThe general strategy of metabolic engineering for the extracellular fatty acid production should be the cyclic optimization between cultivation performance and strain improvements. On the basis of our cultivation process optimization, strain improvements should be further carried out for the effective and cost-effective production process.

An analysis of potential feedstock and location for biodiesel production in Southern Africa

The economics of biodiesel production shows that the cost of raw material is the main driver of the overall production costs. Operation cost of biodiesel production does not reflect significant economy of scale because scale-dependent variable such as labour, chemical and maintenance costs are only a small part of the operating expenses. The success of the biodiesel industry is therefore reliant upon the availability of adequate supplies of reasonably priced feedstocks. The potential oil crops for use in Southern Africa countries for biodiesel production are not well-documented. This paper analyzes the potential availability of biodiesel feedstock in Southern Africa and discusses their suitability, adaptability of the various oils as precursors for biodiesel production. Potential feedstocks are identified which is by no means an all inclusive list but contains major oil crops/feedstock that can be used for biodiesel production. The current and future availability of each feedstock are evaluated and growing regions for dedicated biodiesel oil seeds is proposed using multi criteria decision analysis based on analytic hierarchy process methodology. This paper also discusses the sustainability of using non-food crops as biodiesel feedstock against the backdrop of current biofuel policies and initiatives in Southern Africa. This study provides investment information to potential investors and further set the context for biofuel discussion and development in the African continent.

Lipid composition in microalgal community under laboratory and outdoor conditions

Microalgae are the most sought after sources for biofuel production due to their capacity to utilize carbon and synthesize it into high density liquid. Current energy crisis have put microalgae under scanner for economical production of biodiesel. Modifications like physiological stress and genetic variation is done to increase the lipid yield of the microalgae. A study was conducted using a microalgal consortium for a period of 15 days to evaluate the feasibility of algal biomass from laboratory as well as outdoor culture conditions. Native algal strains were isolated from a tropical freshwater lake. Preliminary growth studies indicated the relationship between the nitrates and phosphates to the community structure through the days. The lipid profile done using Gas chromatography – Mass spectrometry, revealed the profile of the algal community. Resource competition led to isolation of algae, aided in the lipid profile of a single alga. However, further studies on the application of the mixed population are required to make this consortium approach economically viable for producing algae biofuels.

Lipid composition in microalgal community under laboratory and outdoor conditions

Microalgae are the most sought after sources for biofuel production due to their capacity to utilize carbon and synthesize it into high density liquid. Current energy crisis have put microalgae under scanner for economical production of biodiesel. Modifications like physiological stress and genetic variation is done to increase the lipid yield of the microalgae. A study was conducted using a microalgal consortium for a period of 15 days to evaluate the feasibility of algal biomass from laboratory as well as outdoor culture conditions. Native algal strains were isolated from a tropical freshwater lake. Preliminary growth studies indicated the relationship between the nitrates and phosphates to the community structure through the days. The lipid profile done using Gas chromatography – Mass spectrometry, revealed the profile of the algal community. Resource competition led to isolation of algae, aided in the lipid profile of a single alga. However, further studies on the application of the mixed population are required to make this consortium approach economically viable for producing algae biofuels.

A Novel Biodiesel and Glycerol Carbonate Production Plant

Crude glycerol is the byproduct of biodiesel production plant and the economic value of glycerol may affect the profitability of the biodiesel production plant. As the production rate of bioglycerol increases, its market values drop considerably. Therefore, conversion of bioglycerol into value-added products can reduce the overall cost, hence, leading to a more economical biodiesel production plant. In a direct carboxylation reaction, CO2 reacts with glycerol to produce glycerol carbonate and water. This study presents a direct comparison of the economic analysis of the conventional biodiesel production plant and the possible next generation biodiesel-glycerol carbonate production plant. At the end of 15-year project, the net present value of the biodiesel-glycerol carbonate production plant is $13.21 million higher than the conventional biodiesel plant. The stochastic model has predicted that the biodiesel-glycerol carbonate and conventional biodiesel production plants has about 30% and 63% chance of getting negative net present value, respectively. Heterogeneous catalyst, Ca3La1, is used for transesterification reaction to reduce separation steps in the biodiesel production process.

KI-impregnated oyster shell as a solid catalyst for soybean oil transesterification

Research on inexpensive and green catalysts is needed for economical production of biodiesel. The goal of the research was to test KI-impregnated calcined oyster shell as a solid catalyst for transesterification of soybean oil. Specific objectives were to characterize KI-impregnated oyster shell, determine the effect of reaction variables and reaction kinetics. The catalyst was synthesized by impregnating KI on calcined oyster shells. X-ray diffraction analysis indicated the presence of portlandite and potassium iodide on the surface and a 31-fold increase in surface as a result of calcination and KI impregnation. Under the conditions tested, ideal reaction variables were 1mmolg−1 for catalyst loading, 50°C for temperature, 10:1 for methanol/oil, and 4h for reaction time. The transesterification followed a first-order reaction (k=0.4385h−1). The option of using oyster shell for the production of transesterification catalysts could have economic benefits to the aquaculture industry in the US.

Simplifying biodiesel production: The direct or in situ transesterification of algal biomass

AbstractThe in situ esterification/transesterification of algal biomass lipids to produce FAME for potential use as biodiesel was investigated. Commercial algal biomass was employed, containing 20.9 wt% hexane extractable oil. This consisted of 35.1 wt% free fatty acids (FFA), 18.2 wt% TAG, and 8.8 wt% MAG, accounting for 62.1% of the extractable material. Other constituents of the hexane extractable material, accounting for 37.9% of the extracts, were not further characterized. The predominant fatty acids in the oil were palmitic (42.4 wt%), oleic (30.6 wt%), linoleic (22.8 wt%), and linolenic (16.1 wt%). Small amounts of 10‐keto 16:0 and 10‐OH 16:0 fatty acids were also present. Statistical experimental design was employed to coordinately examine the effects of the amounts of methanol, sulfuric acid, and reaction temperature (23–65°C) on the yield of FAME in 2 h reactions. Three methods of feedstock preparation were examined – as received, oven dried, and water‐washed/dried. For all feedstocks conditions could be identified which were predicted to yield greater than 90% maximum theoretical FAME production. Oven drying the feedstock reduced the amount of methanol required, with 83% of maximum yield obtained at a methanol/fatty acid molar ratio of 220:1 (4 mL methanol/g substrate). Water washing the biomass did not reduce the methanol required for high level transesterification.Practical applications: In biodiesel production by the conventional method of alkali‐catalyzed transesterification of a refined vegetable oil/the combination of feedstock and process costs threatens the economic viability of biofuel production. In situ esterification/transesterification is a method for producing biodiesel wherein a lipid‐bearing material is directly treated with reagents that catalyze fatty acid alkyl ester production from FFA and acylglycerols. By eliminating the need to isolate and refine the feedstock lipid, this approach to biodiesel production eliminates some of the processing steps required by contemporary methods. This could provide a welcome reduction in the cost of biodiesel production. There is presently considerable interest in the possibility of biofuel production from algal biomass. This study describes the application and optimization of in situ transesterification to a lipid‐bearing algal biomass. Application of this technology could facilitate the economical production of biodiesel from algal biomass.

화학응집제를 이용한 미세조류의 응집 특성

The aim of the study was to optimize harvesting method for concentrating microalgae from microalgae mass culture. It is well known that the mass density of microalgae is usually very low and these are small size (5-20 μm) in the culture medium. It is essential that microalgae is harvested and concentrated economically for economical biodiesel production from microalgae. In this study, to determine optimized conditions for microalgae harvesting by chemical flocculation. Flocculation of three algae, Chlorella ellipsoidea, Dunaliella bardawil, and Dunaliella tertiolecta, was performed using various chemical flocculants, such as inorganic flocculants (aluminium sulfate, aluminium potassium sulfate, ferrous sulfate, ferric sulfate, ferric chloride, calcium hydroxide, sodium carbonate, sodium nitrite, and sodium aluminate), organic flocculant (polyacrylamide), and biopolymer flocculants (chitosan and starch). The results indicated that aluminium based inorganic flocculants is suitable for microalgae harvesting such as Chlorella ellipsoidea, Dunaliella bardawil, and Dunaliella tertiolecta. The results also recommended that flocculant doses, agitation speed, agitation time, sedimentation time for economical microalgae harvesting method using chemical flocculants.

Two-step bioprocess employing whole cell and enzyme for economical biodiesel production

A preliminary research for feasible and economical bioprocess for biodiesel production was carried out. A microorganism producing lipase was isolated from grease-contaminated soil. After chemically mutating twice, the microorganism exhibited 2.5 times higher intracellular lipase activities than wild type one and was used as a whole cell biocatalyst for biodiesel production. 0.1% toluene treatment followed by freeze drying was the optimum preparation method for whole cell biocatalyst. 1 g whole cell biocatalyst corresponded to 0.15 g commercial enzyme under mild methanol inhibition condition, while corresponding to 0.7 g enzyme under severe methanol inhibition environment. A two-step process, biodiesel production by the whole cell and sequentially by commercial enzyme, was suggested. This novel process, combining the advantages of whole cell and enzyme, saved the usage of commercial enzyme and alleviated enzyme deactivation by methanol.

Characterization and optimization of extracellular alkaline lipase production by Alcaligenes sp. Using stearic acid as carbon source

The aim of this study was to improve the production of an extracellular alkaline lipase from Alcaligenes sp. (ATCC 31371) by optimization of the culture medium, for economic production of biodiesel from waste vegetable oil. A number of carbon sources including different types of starch, sugar, sugar alcohol, organic acids, and surfactants were investigated. Polyoxyethylene (20) sorbitan tristearate, whose side chain is stearic acid, was the most effective carbon source for lipase production. Box-Behnken experimental design was used for three factors (soy protein, sodium nitrate, and stearic acid) and the optimal composition for maximum lipase production (1.7-fold enhancement) was established as soy protein 4.07%, sodium nitrate 0.17%, and stearic acid 0.28% at 28°C with an agitation rate of 220 rpm for 24 h. The enzyme was purified to homogeneity and the recovery of the lipase activity was 7.8% with a 30-fold purification. The estimated molecular size of the protein determined by SDS-PAGE was 33 kDa. The optimum pH and temperature of the purified lipase was 8.5 and 40°C, respectively. The purified enzyme was stable in the pH range of 6.0 and 9.5 and in the temperature range of 20 and 50°C.

Esterification of free fatty acids in waste cooking oils (WCO): Role of ion-exchange resins

Although WCO plays a crucial role for the economical production of biodiesel, free fatty acid (FFA) level in the nature of WCO cause saponification problems during transesterification. Acidic ion-exchange resins can be used to decrease WCO free fatty acid level. In this study, activities of resins (Amberlyst-15 (A-15), Amberlyst-35 (A-35), Amberlyst-16 (A-16) and Dowex HCR-W2) in direct FFA esterification were examined in the temperature range of 50–60°C and the effect of catalyst amount (1–2wt%) on FFA conversion was also analyzed. FFA conversion increased with increasing reaction temperature and catalyst amount. Order of catalytic activities was found as A-15>A-35>A-16>Dowex HCR-W2. This was related to the size of average pore diameters and magnitude of BET surface area.

Production of alkyl esters from tallow and grease using lipase immobilized in a phyllosilicate sol‐gel

AbstractThe lipase‐catalyzed synthesis of alkyl esters from tallow and grease using Pseudomonas cepacia lipase (PS‐30) immobilized within a phyllosilicate sol‐gel matrix was investigated. The effects of the presence of alcohol and of the amount of enzyme used were studied. The matrix‐immobilized PS‐30 lipase effectively converted grease and tallow to ethyl esters in greater than 95% yield when using ethanol. The final conversion of grease or tallow to alkyl esters was aided by the addition of molecular sieves (0.4 wt% of substrates) to the reaction mixture. The matrix‐immobilized PS‐30 enzyme was easily recovered and could be reused at least five times without losing its activity. Accordingly, the phyllosilicate sol‐gel immobilized PS‐30 lipase is potentially useful for the economic production of biodiesel fuel.