Neochloris oleoabundans grown on anaerobically digested dairy manure for concomitant nutrient removal and biodiesel feedstock production

Microalgae have been investigated as a promising biodiesel feedstock; however, large-scale production is not currently cost-competitive with petroleum diesel, and its environmental impacts have received little attention. Using wastewater to supply nutrients for algal growth obviates synthetic fertilizer use, provides on-site nutrient removal, and reduces greenhouse gas emissions. In this work, anaerobically digested dairy manure was used to grow the oleaginous green alga Neochloris oleoabundans. In batch culture experiments with both synthetic media and anaerobic digester effluent, N. oleoabundans assimilated 90-95% of the initial nitrate and ammonium after 6 d and yielded 10-30% fatty acid methyl esters on a dry weight basis. Cellular lipid content and the N concentration in the growth media were inversely correlated. In addition, the proportion of polyunsaturated fatty acids (i.e. C16:3, C18:2, and C18:3) decreased with N concentration over time while the proportion of C18:1 fatty acid increased. Although N deficiency is likely the primary driver behind lipid accumulation, the influence of culture pH confounded results and requires further study. Other living microorganisms in the digester effluent were not observed to affect algal growth and lipid productivity, though the breakdown of organic nitrogen may have hindered lipid accumulation traditionally achieved through the manipulation of synthetic media. This work highlights the potential for waste-grown mono-algal cultures to produce high quality biodiesel while accomplishing simultaneous wastewater treatment.     

Culture of microalgal strains isolated from natural habitats in Thailand in various enriched media

Six freshwater microalgal strains in the class of Chlorophyceae, including Chlorococcum humicola, Didymocystis bicellularis, Monoraphidium contortum, Oocystis parva, Sphaerocystis sp., and Scenedesmus acutus were isolated from natural habitats in Thailand. The six strains were compared for their biomass yield, lipid content, and lipid productivity in four enriched culture media in batch mode. Significant differences were found across algal strains and culture media. The best strain was found to be C. humicola, which had the highest biomass yield of 0.113 g/l/d (in Kuhl medium), the highest lipid content of 45.94% (in BG-11 medium), and the highest lipid yield of 0.033 g/l/d (in 3NBBM medium). The 3NBBM medium, which has the lowest nitrogen concentration among the four culture media, was considered the optimal culture medium for C. humicola for lipid production. The fatty acid profile of C. humicola was also found to be affected by the culture medium. More oleic acid (C18:1) but less linolenic acid (C18:3) was accumulated in BG-11 and 3NBBM than in Kuhl and N-8 media. Lipid profiles of C. humicola were comparable to palm oil in the percentage of palmitic acid and the total amount of saturated fatty acids; however, C. humicola made more poly-unsaturated fatty acids such as linoleic (C18:2) and linolenic (C18:3) acids than oil palms. Lipids from C. humicola were believed to be acceptable for biodiesel production.     

Effects of enzymatic hydrolysis on lipid extraction from Chlorella vulgaris

In this study, the effects of enzymatic hydrolysis on lipid extraction from microalga (Chlorella vulgaris) were investigated prior to biodiesel production. The initial fatty acids content of C. vulgaris was 87.6 mg/g cell. The microalgal cell walls were hydrolyzed by cellulases and then their lipid fractions were extracted using various organic solvents such as hexane, methanol, and chloroform. Optimal pH and temperature for the enzymatic hydrolysis were pH 4.8 and 50 °C, respectively, and the maximal hydrolysis yield was 85.3%, which was achieved after 72 h. After the enzymatic hydrolysis, the lipid extraction yield by the organic solvents was improved compared to when there was no enzymatic hydrolysis process, by 1.29–1.73-fold depending on the solvents used. The total fatty acid methyl ester (FAME) productivity through the enzymatic hydrolysis was higher than when there was no enzymatic hydrolysis, by 1.10–1.69-fold depending on the solvents used. When lipid was extracted from the C. vulgaris after the enzymatic hydrolysis in chloroform-methanol solution, FAME productivity was 59.4 mg FAME/g cell.     

Prospecting the biofuel potential of new microalgae isolates

The continued search and urgent need for renewable fuel sources have necessitated the exploration of microalgae to identify relevant species for making biofuels. The aim of the study was bioprospecting and screening native microalgae strains from freshwater habitats of the Almaty region, Kazakhstan, to assess the potential for producing biofuel. The studied strains demonstrated simultaneous biomass productivity, lipid productivity, suitable fatty acid composition, and biodiesel properties. The sequence analysis of the ribosomal DNA internal transcribed spacer partial region and ribulose-bisphosphate carboxylase gene (rbcL) led to the identification of five microalgae: Monoraphidium griffithii ZBD-01, Nephrochlamys subsolitaria ZBD-02, Ankistrodesmus falcatus ZBD-03, Parachlorella kessleri ZBD-04, and Desmodesmus pannonicus ZBD-05. P. kessleri had the highest biomass production (1.42 ± 0.08 g L⁻¹ day⁻¹), lipid productivity (29 ± 1.2 g L⁻¹day⁻¹), and C₁₆–C₁₈ fatty acid contents (90%), followed by A. falcatus and M. griffithi. Gas chromatography/mass spectrometry analysis indicated that the dominant fatty acids in these strains were palmitic, stearic, and oleic acids. The calculated biodiesel properties of P. kessleri and A. falcatus based on fatty acid methyl esters (FAME) profiles showed relatively good fuel properties (cetane numbers - 48 and 50; iodine and saponification values - 83.4 and 103.6 g I₂/100 g oil, 260.8 and 199.5 mg KOH g⁻¹), which correlate well with. Our results suggest that P. kessleri and A. falcatus are promising strains for biodiesel production due to their high lipid productivity, fatty acid profile with relatively high content of oleic acid, and suitable biodiesel properties. The isolated native species of microalgae from natural freshwater bodies of the Almaty region present opportunities for further exploitation for the sustainable production of biomass and biodiesel.     

Bioconversion of organic wastes into biodiesel and animal feed via insect farming

Approximately one-third of all food produced for human consumption worldwide is wasted. The current waste management practices are not only costly but also have adverse impact on environment. In this study, black soldier fly (BSF) (Hermetia illucens) larvae were grown on food wastes to produce fat and protein-rich BSF prepupae as a novel strategy for efficient organic waste management. The lipid content in BSF prepupae was characterized for fatty acids profile. Whole BSF prepupae, pressed cake, and meal were analyzed for important animal feed characteristics. BSF-derived oil has high concentration of medium chain saturated fatty acids (67% total fatty acids) and low concentration of polyunsaturated fatty acids (13% total fatty acids), which makes it potentially an ideal substrate for producing high quality biodiesel. BSF (prepupae, pressed cake, and meal) has feed value comparable to commercial feed sources. Thus, the bioconversion of organic waste into BSF prepupae has significant potential in generating high-value products with simultaneous waste valorization.     

Co-production of biodiesel and alpha-linolenic acid (omega-3 fatty acid) from microalgae,Desmodesmus sp. MCC34

Microalgae are a potential source of biofuel and nutraceuticals. In the present study, Desmodesmussp. MCC34 was identified as a promising species for biodiesel and omega-3 fatty acid productions after initial screening since it had displayed the highest lipid productivity of 15.9 mg L^?1 day^?1 and alpha-linolenic acid of 24% of total fatty acids. Using silver ion chromatography, 92% of pure alpha-linolenic acid was selectively removed from total lipid of Desmodesmussp. MCC34, while the residual oil having a higher amount of saturated and monounsaturated fatty acids displayed biodiesel property adhering to international standards, suggesting fuel co-application.

Abbreviations: ALA: alpha-linolenic acid methyl ester; GLAME: gamma-linolenic acid methyl ester; FAME: atty acid methyl ester; SFA: aturated fatty acid; MUFA: monounsaturated fatty acid; PUFA: polyunsaturated fatty acid.     

Production of microbial oil with high oleic acid content by Trichosporon capitatum

Microbial oils with high unsaturated fatty acids content, especially oleic acid content, are good feedstock for high quality biodiesel production. Trichosporon capitatum was found to accumulate lipid with around 80% oleic acid and 89% total unsaturated fatty acids content on nitrogen-limited medium. In order to improve its lipid yield, effects of medium components and culture conditions on cell growth and lipid accumulation were investigated. Optimization of media resulted in a 61% increase in the lipid yield of T. capitatum after cultivation at 28 °C and 160 rpm for 6 days. In addition, T. capitatum could grow well on cane molasses and afford a lipid yield comparable to that on synthetic nitrogen-limited medium. The biodiesel from the microbial oil produced by T. capitatum on cane molasses displayed a low cold filter plugging point (−15 °C), and so T. capitatum might be a promising strain to provide lipid suitable for high quality biodiesel production.     

Biomass and lipid productivities of marine microalgae isolated from the Persian Gulf and the Qeshm Island

In this work, the screening of 147 microalgal strains from the Persian Gulf and the Qeshm Island (Iran) were done in order to choose the best ones, in terms of growth (biomass) rate and lipid content for biodiesel production. A methodology, combining experiments in lab-scale and pilot plant (open pond) used to produce and evaluate biomass and lipid productivity is presented for the systematic investigation of the potential of different microalgae species. The culture conditions, including photo flux (180 ??E m⁻² s⁻¹), photoperiod (12 h light/dark), temperature (25 °C), pH (≈8), air (carbon dioxide) and growth medium, were kept constant for all experiments. Microalgae were screened in two stages using optical density (for evaluation of biomass concentration) and Nile red and gas chromatography (for determination of lipid content and fatty acid fractions). In general, maximum specific growth rate and the maximum biomass productivity were obtained after 8-12-day culture. Nannochloropsis sp. and Neochloris sp. were selected from the marine microalgal culture collection, due to their high biomass (50 and 21.7 g L⁻¹, respectively) and oil content (52% and 46%, respectively). If the purpose is to produce biodiesel only from one species, Nannochloropsis sp. presented the most adequate fatty acid profile, namely linolenic and other polyunsaturated fatty acids. However, the microalgae Chlorella sp. can also be used if associated with other microalgal oils. In addition, selected strains could be potent candidates for commercial production in the open pond culture.     

A potent lipid producing isolate of Epicoccum purpurascens AUMC5615 and its promising use for biodiesel production

Oils of oleaginous microorganisms are a powerful alternative to vegetable oils for biodiesel production. In this study, the fungus Epicoccum purpurascens AUMC5615 isolated from Egypt showed a potent high lipid content (80% lipid) when grown on 4% sucrose in submerged culture under continuous illumination. Under dark submerged conditions the lipid content has drastically decreased to 12%. In light static conditions, the lipid content was 70%; however, the net lipid yield was significantly lower than that of light submerged cultures because of the decrease in growth under light static conditions in comparison to light submerged cultures. Under dark static conditions the lipid content of the fungus has declined to 30%. These results indicate that light plays a crucial role in the lipid accumulation whereas submersion enhances the growth of the fungus. Concomitantly, the highest yield of carotenoids was obtained under light submerged conditions followed respectively by light static, dark submerged and dark static. This synchronized increase in carotenoids content might be implicated in protecting the high lipid pools in the fungus from peroxidation. Growing the fungus on 4% of crude molasses resulted in a net lipid production of 26.8 g per liter under light submerged conditions. The determination of fatty acids by GC/MS revealed that the major constituents are four saturated fatty acids, hexadecanoic, n-decanoic, dodecanoic and octadecanoic acids. These saturated fatty acids would give valuable stability properties of such fungal biodiesel. The current investigation opens the scope for the possible use of this promising fungal isolate in biodiesel production.     

Characterization of fatty acids and hydrocarbons of chlorophycean microalgae towards their use as biofuel source

Microalgae accumulate important biofuel precursors such as fatty acids and hydrocarbons. Identification of microalgal strains with ideal fuel quality precursor profile is important during bioprospection studies. In this direction, thirty two freshwater green microalgae were characterized for their biomass productivity, fatty acid and hydrocarbon composition under autotrophic growth conditions. Scenedesmus dimorphus CFR 1-05/FW, Oocystis pusilla CFR 6-01/FW and Quadrigula lacustris CFR 7-01/FW were high biomass producing strains with shorter doubling time. Lipid accumulation was monitored by nile red staining with mild acetic acid pretreatment (at 7 m mol L⁻¹) to microalgal cells. Six strains viz., S. dimorphus CFR 1-05/FW, Scenedesmus obtusus CFR 1-09/FW, Chlorococum sp. CFR 2-01/FW, C. humicola CFR 2-03/FW, Chlorella sorokiniana CFR 3-01/FW, Dictyosphaerium CFR 5-01/FW showed lipid accumulation of >20% mass fraction at stationary phase. Palmitic, oleic and alpha linolenic acids were major fatty acids in all the chlorophycean species. Fuel grade hydrocarbons which can be directly blended with petroleum fuels were identified. Fourteen strains showed hydrocarbon content of >10% mass fraction of dry biomass. n-Paraffins of chain length between C15 to C20 were predominant hydrocarbons in all the strains. Branched isoprenoid hydrocarbons were detected in Scenedesmus sp. CFR 1- 13/FW constituting 49% mass fraction of total hydrocarbons. High quantities of n-tetradecane (40%) was detected in Kirchneriella cornuta CFR 8-01/FW. The similarity of microalgal hydrocarbon profiles with paraffinic and isoparaffinic fraction of petroleum diesel and compliance of FAME based biodiesel to international standards indicate the suitability of algae derived biofuels for blending with conventional petroleum fuels.     

Isolation and identification by 18S rDNA sequence of high lipid potential microalgal species for fuel production in Hainan Dao

To exploit indigenous microalgal species with the potential for biodiesel production, 101 algal cultures were isolated from partial waters in Hainan province. Eight cultures were selected based on their high biomass, high lipid content and ease of cultivation, then identified based on morphology and 18S rDNA sequence analysis. These isolates were identified as Tetranephris brasiliensis DL12, Ankistrodesmus gracilis DL25, Ankistrodesmus sp. CJ02, Desmodesmus subspicatus WC01, A. gracilis CJ09, Chlorella vulgaris CJ15, Desmodesmus sp. WC08, Chlorella sorokiniana XS04, respectively. Desmodesmus sp. WC08 reached the highest biomass concentration (2.32 g L⁻¹) with the lipid content of 31.30%. Higher lipid content of 47.90% and 47.39% were gained by A. gracilis CJ09 and C. vulgaris CJ15, respectively. However, C. vulgaris CJ15 and Desmodesmus sp. WC08 had higher lipid productivity (117.37 mg L⁻¹ d⁻¹and 115.73 mg L⁻¹ d⁻¹, respectively) in terms of comprehensive consideration. The fatty acid compositions of these microalgal species were mainly palmitic, palmitoleic, stearic, oleic with GC–MS (gas chromatography–mass spectrometer) analysis. A. gracilis CJ09, T. brasiliensis DL12, A. gracilis DL25 and Desmodesmus sp. WC08 had the higher oleic acid content (over 50% of the total fatty acids) than the others. The results suggest that marine microalgae strain Desmodesmus sp. WC08 can be the most appropriate candidate for producing oil for biodiesel, based on its higher biomass productivity, lipid productivity and fatty acid profile.     

Search for new strains of microalgae-producers of lipids from natural sources for biodiesel production

Biomass of high-yielding strains of phototrophic microorganisms actively accumulating lipids is a promising non-traditional raw material for bioenergy including the production of biodiesel. In this study, we present results of searching for new strains of microalgae-producers of lipids from hot springs. Within the framework of research, the primary screening of water for the presence of lipid - accumulative microalgae was carried out with the help of qualitative reaction with lipid-specific dyes, as well as 5 axenic isolates of microalgae with stable growth were identified in the laboratory and their productivity and fatty acid composition were studied. The isolated strains were identified as Chlorella vulgaris sp-1, Ankistrodesmus sp-21, Scеnеdеsmus obliquus sp-21, Chlorella pyrenoidosa sp-13 and Chlamydomonas sp-22. The obtained data showed that the isolated strains determined by biomass in the range 1.3 g/l to 1.81 g/l. As a result of the research, it was established that the highest content of lipids was observed in the strains Chlorella vulgaris sp-1 and Scеnеdеsmus obliquus sp-21, which is 28.7 and 29.8% of the cell dry weight, respectively. The analysis of the fatty acid composition of the cells showed that the largest mass fraction of saturated and monounsaturated fatty acids was found in strain Scеnеdеsmus obliquus sp-21 - 61.9%. In the result, Scеnеdеsmus obliquus sp-21 strain isolated from thermal sources was selected as a promising candidate for biodiesel production.     

Optimization of conversion of waste rapeseed oil with high FFA to biodiesel using response surface methodology

In the present study, waste rapeseed oil with high free fatty acids (FFA) was used as feedstock for producing biodiesel. In the pretreatment step, FFA was reduced by distillation refining method. Then, biodiesel was produced by alkaline-catalyzed transesterification process, which was designed according to the 2⁴ full-factorial central composite design. The response surface methodology (RSM) was used to optimize the conditions for the maximum conversion to biodiesel and understand the significance and interaction of the factors affecting the biodiesel production. The results showed that catalyst concentration and reaction time were the limiting conditions and little variation in their value would alter the conversion. At the same time, there was a significant mutual interaction between catalyst concentration and reaction time.The biodiesel produced in the present experiment was analyzed by gas chromatography/mass spectrometry (GC/MS), which showed that it mainly contained six fatty acid methyl esters. In addition, the diesel indexes analysis showed that most of the fuel properties were in reasonable agreement with the 0# diesel standard of China (GB252-2000) and the biodiesel standard of America (ASTM D6751).     

Jet range hydrocarbons converted from microalgal biodiesel over mesoporous zeolite-based catalysts

In order to produce jet biofuel from lipids derived from microalgal biomass, lower-viscosity and smaller-molecular microalgal biodiesel was converted into jet range hydrocarbons over four mesoporous zeolite-based catalysts decorated with nickel. Ni/Meso-Y catalyst exhibited a high selectivity (44.5%) of jet range alkane (C₈C₁₆) from light microalgal biodiesel. The conversion pathway of light microalgal biodiesel to jet range hydrocarbons was proposed that majority of fatty acids first deoxygenated to C₁₅C₁₆ through decarbonylation and then long chain alkane cracked into short chain alkane. The other fatty acids first cracked into short chain acids and then further deoxygenated through decarbonylation to jet range alkane, in which a part of alkane converted to aromatic hydrocarbons through aromatization. Meso-Y catalyst was suitable for conversion of heavy microalgal biodiesel to jet range hydrocarbons with low selectivity (4.47%) of aromatic hydrocarbons, but the other three catalysts (Meso-HZSM-5, Meso-Hbeta and SAPO-34) gave high aromatic hydrocarbons selectivity.     

Screening of marine microalgae for biodiesel feedstock

Biodiesel production from microalgae lipids is increasingly regarded as a more sustainable and feasible alternative to conventional biodiesel feedstocks derived from terrestrial bioenergy crops. A total of ninety-six strains of marine microalgae, with an elevated biomass productivity and intracellular lipid content, were isolated from the coastal waters of Singapore using an automated flow cytometric cell-sorting technique. Cell sorting was based on the two-dimensional distribution of algal cells for red fluorescence (representing chlorophyll auto-fluorescence) against forward-light scatter (representing cell size) and red vs. green fluorescence. Twenty-one of the strains were further characterized with respect to cell growth rate, biomass concentration, lipid content (total and neutral lipid) and fatty acid profile. The growth rates of Skeletonema costatum, Chaetoceros and Thalassiosira species were greatest among the entire strains, but in terms of absolute lipid yield Nannochloropsis strains predominated. Nannochloropsis strains had a lipid content ranging from 39.4% to 44.9% of dry weight biomass. Transesterification of the lipids yielded 25-51% of fatty acid methyl ester (FAME) i.e. biodiesel, where total FAME content ranged between 11 and 21% of dry weight biomass. This study describes the microalgae screening process and demonstrates that Nannochloropsis is a promising species for biodiesel feedstock.     

Oil assessment of Halamphora coffeaeformis diatom growing in a hybrid two-stage system for biodiesel production

The lipid content, composition and productivity of the marine benthic diatom Halamphora coffeaeformis were studied in order to evaluate its potential as feedstock for biodiesel production. Cultures were carried out in two stages: I) in photobioreactors (PBRs) to increase the biomass as inoculum for larger volumes, and II) in raceway ponds to increase naturally the triacylglycerol (TAG) content during the stationary growth phase. Biomass concentrations of 0.64 g L⁻¹ and 0.23 g L⁻¹ were reached in the PBR and the raceway pond, respectively. Total lipid content was 54.4 (±11.6) % ash free dry weight (AFDW) in the raceway pond on day 19 (harvest day), with a neutral lipid content of 34% AFDW. The TAG productivity in the raceway pond was 1.2 mg L⁻¹ d⁻¹. The indicators of biodiesel, calculated from fatty acid profile composition, showed that H. coffeaeformis oil was of good quality, according to international standards. Some hypothetical aspects are proposed in order to improve lipid productivity and net energy ratio in processes at larger scales.     

Cyprinus carpio fish oil: A novel feedstock for biodiesel production

Biodiesel was developed from a novel nonedible oil source, namely Cyprinus carpio fish oil. The acid value of fish oil was very low (0.70 mg KOH/g oil, 0.35 free fatty acid content). As a result, biodiesel was produced through a one-step transesterifcation process, i.e. alkali-catalyzed transesterification with methanol. The optimal conditions for producing biodiesel from fish oil were investigated. The highest biodiesel yield (97.22% ~ 96.88% w/w ester content) was obtained under optimum conditions of 0.75% KOH w/w, 7:1 methanol to oil molar ratio, 60°C reaction temperature and 60-minute duration. Properties of the produced biodiesel as well as its blends with petro-diesel fulfilled the standard limits as prescribed by ASTM D6751 and EN 14214 indicating its suitability as a fuel for diesel engines.     

Effect of carbon supply mode on biomass and lipid in CSMCRI's Chlorella variabilis (ATCC 12198)

CSIR-CSMCRI's Chlorella variabilis (ATCC 12198) was evaluated through autotrophic, mixotrophic and heterotrophic growth for lipid production. Autotrophic growth was assessed by providing sodium bicarbonate/sodium carbonate/CO₂ (air in a medium). Higher lipid productivity (115.94 mg L⁻¹ d⁻¹) with higher biomass productivity (724.98 mg L⁻¹ d⁻¹) of this strain was attained through bicarbonate and CO₂ sequestration in a photobioreactor. Ability to regulate the pH in favorable bicarbonate/carbonate ratio showed its potential in alkaline effluent based carbon sequestration system for biofuel generation. The simultaneous study was also conducted to understand the effect of elevated CO₂ (0.4, 1 and 1.2 g L⁻¹) in air on the culture to assess adaptation, growth and lipid in the closed chamber conditions. It was observed that CO₂ sequestration by the microalgae from the CO₂ enriched environment was optimum at 1 g L⁻¹ C. variabilis adapted to comparatively higher CO₂ (1 g L⁻¹) but grew better in low CO₂ (0.4 g L⁻¹). It was also observed that the growth, lipid content and fatty acid composition was significantly affected by CO₂ supply strategies. The effect of intermittently added sodium bicarbonate at different pH on microalgal lipid content and composition of fatty acids was observed which could affect the quality of biodiesel. The effect on fatty acid composition was observed in response to carbon supply mode during the microalgal growth at different pH dictating the properties of biodiesel.     

Analysis of performance and emission patterns of novel biofuel feedstock neat coconut fatty acid distillate (CFAD) fuelled single-cylinder diesel engine

This study examined the potential of using coconut fatty acid distillate (CFAD), a by-product of the processing of edible oils, as a diesel engine fuel. The major novelty of this study is to assess the CFAD as a viable feedstock of biodiesel to address global energy demands. CFAD has not been specifically researched as a feedstock for producing biodiesel or as a fuel for diesel engines, despite the fact that numerous studies on the production and performance of biodiesel have already been conducted. Fourier transform infrared (FTIR) spectroscopy, gas chromatography (GC), and FTIR were used to analyze the fuel. According to the results of the GC test, CFAD oil contains 91.53% saturated fatty acids, compared with only 8.47% unsaturated fatty acids. High saturation values can be seen in myristic acid (16.92%) and lactic acid (45.33%). Longer hydrocarbon chain lengths indicate higher energy density and boiling point, which also indicate lesser volatility. At a frequency of 1708.54 cm⁻¹, C─H stretching vibrations have been identified through FTIR investigation. The vibrations of C─C stretching at 1465.47 cm⁻¹ indicate the presence of alkenes/fingerprint phase. The blends used for this investigation include 90% diesel with 10% CFAD (CFAD10), 80% diesel with 20% CFAD (CFAD20), 70% diesel with 30% CFAD (CFAD30), and 100% CFAD. The CFAD 10%, 20%, and 30% blends as well as the CFAD100 had brake thermal efficiency values of 27.24%, 26.23%, 24.88%, and 21.52%, correspondingly, at full load. The average increment in brake-specific energy consumption for CFAD10, CFAD20, CFAD30, and CFAD100 over diesel fuel was 8.23%, 10.88%, 13.77%, and 25.90%, respectively. The behavior of CFAD exhibits reduced cylinder pressure because of the large content of moderate saturated fatty acids in this substance. The net heat release rate (NHRR) and cylinder pressure have a similar relationship in that the NHRR increases with increasing diesel volume. In comparison to diesel, the CO emissions from the CFAD20, CFAD30, and CFAD100 blends increased by 10.79%, 16.66%, and 35.89% at maximum load, respectively. It has been reported that NO_x is reduced more significantly the more CFAD is present in the mixture. The blend CFAD10 had the least amount of smoke. The high viscosity of the CFAD and its blends influences the fuel droplets range and the development of spray in the cylinder, which results in delayed combustion and higher unburned hydrocarbon emissions.     

Renewable energy sources from Michelia champaca and Garcinia indica seed oils: A rich source of oil

Michelia champaca and Garcinia indica seeds yielded 45.0% and 45.5% of oil. The fatty acid profiles of both the seed oils were examined. The saponification value (SV), iodine value (IV) and cetane number (CN) of fatty acid methyl esters of both the seed oils were empirically determined. The saponification value (SV) and iodine value (IV) are in good agreement with the experimentally observed values. The fatty acid compositions, iodine value and cetane number were used to predict the quality of fatty acid methyl esters of oil for use as biodiesel. Thus, the fatty acid methyl esters of seed oils of M. champaca and G. indica were found to be the most suitable biodiesel and they meet the major specification of biodiesel standards. The selected plants M. champaca and G. indica have great potential for biodiesel. M. champaca and G. indica seed oils were found to contain keto fatty acids along with the other normal fatty acids, respectively. These fatty acids have been detected and characterized by UV, FTIR, ¹H NMR, ¹³C NMR, MS, GC techniques and chemical transformations.