Table 3.

Summary of aerobic laboratory studies of biodegradation of FAME and FAME–diesel blends

ReferenceSource of inoculumMediaMeasurementFAME and other substratesReported results
Peterson & Reece (1994)Not specified; however, BOD tests generally use sewage sludge and shake flask test generally uses a weak bacterial inoculumAqueous solution (not further described); no abiotic control reportedBOD; measurement for shake flask test not described, but is generally DOCRapeseed methyl esters (RME) and rapeseed ethyl esters (REE) (probably synthesized at the university); diesel; dextroseHigh BOD for RME and REE; in the shake flask test, 95% biodegradation of RME and REE within 28 days, compared with 40% of diesel; rate of degradation of RME similar to that of REE, but faster than that of dextrose and diesel
Stolz et al. (1995)Pond or lake water; topsoil; culture grown on soybean FAMEMineral salt mediumGC; methanol (by Draeger tubes)Soybean FAME100% FAME disappeared within 7 days with biomass and methanol production; nine aerobic FAME-degrading bacteria were isolated; detected esterase activity
Zhang et al. (1998)Organic-rich soil and aerated activated sewage sludge (unacclimated to FAME)Yeast extract, amino acids, mineralsCO2 production; GCSoybean and rapeseed FAME; soybean and rapeseed ethyl esters (SEE and REE) synthesized at the university using transesterification; neat rapeseed oil, neat soybean oil; Phillips 2-D reference diesel; blends of REE and dieselIn 28 days, 85.5% soybean FAME and 88.5% rapeseed FAME were mineralized to CO2 compared with 87.8% for dextrose, 76.0 – 78.5% for the neat oils and 26.2% for diesel; as measured by GC, 100% of rapeseed ethyl ester disappeared within 3 days
Pasqualino et al. (2006)Two different activated sludge samplesWater with mineral mediaCO2 productionFAME from waste cooking oil (from BIONET Europa); diesel and gasoline from fuel station; blends of waste cooking oil FAME with diesel and gasolineIn 28 days, almost 100% of the FAME was mineralized to CO2, whereas diesel and gasoline were mineralized at 50 and 56%
Makareviciene & Janulis (2003)Unspecified bacterial cultureNatural waterInfrared absorbanceRapeseed methyl ester; rapeseed ethyl ester; dieselIn 21 days, about 98% of RME and REE had degraded, compared with 61% of diesel
Schleicher et al. (2009)Culture isolated from uncontaminated soilWater with nutrientsAcid number by titration; microbial enumerationRapeseed methyl ester (commercial); diesel; B5, B10, B20 blends of the aboveIncrease in free fatty acid content when rapeseed methyl ester was incubated with a microbial culture; higher microbial numbers in B100 incubated under anaerobic than aerobic conditions
Russell et al. (2005)Potting soilPotting soilGCSoybean alkyl esters (ester not specified)In 28 days, 80 – 90% of the soybean alkyl ester had disappeared
Peterson & Moller (2005)Sewage sludgeAqueousBOD by EPA Method 405.1Soybean and rapeseed methyl esters; rapeseed ethyl esters; neat soybean oil and rapeseed oil; Phillips 2-D reference dieselBOD for methyl and ethyl esters and neat oils range from 1.5 to 1.7 × 106 mg l−1, compared with 0.4 × 106 mg l−1 for petroleum diesel
DeMello et al. (2007)Seawater (unacclimated to FAME)SeawaterGCFAME (parent oil not specified, but containing C13 to C18); commercial diesel; B20 blend of the above90% degradation of FAME within 21 days, compared with no loss in abiotic control
Mariano et al. (2008)River water, or soil from a petrol station with low fuel concentrationRiver water or soil from petrol stationCarbon dioxide (CO2) productionLaboratory-prepared castor oil alkyl ester blended with diesel to B5 and B20; commercial diesel and B2 (biodiesel component not specified)CO2 production from castor oil alkyl ester was 1.6-fold higher than for diesel
Owsianiak et al. (2009)Microbial consortium isolated from a crude oil site; identified by 16SrRNA to contain Pseudomonas alcaligenes, Ochrobactrum intermedium, Sphingobacterium sp., Pseudomonas putida, Klebsiella oxytoca, Chryseobacterium sp. and Stenotrophomonas maltophilia; maintained in laboratoryMineral medium at pH 7GCCommercial rapeseed methyl esters; diesel (EN 590:2004); B5, B10, B20, etc. blends of the above prepared in the laboratoryWithin 7 days, 76% disappearance of RME, compared with 42% of diesel
Cyplik et al. (2011)Microbial consortium isolated from crude oil site under aerobic conditions containing Achromobacter sp., Alcaligenes sp., Citrobacter sp., Comamonadaceae, Sphingobacterium sp., Pseudomonas sp. and Variovorax sp.Mineral medium at pH 7GCCommercial rapeseed methyl esters; diesel (EN 590:2004); B20 blends of the above prepared in the laboratoryWithin 5 days, complete disappearance of RME, compared with 10% disappearance of RME in the abiotic control and 20% diesel
Prince et al. (2008)Rainwater from detention pond (unacclimated to FAME)Pond water plus mineral salt mediumGCCommercial soybean methyl esters; B20 (soybean FAME)Half-lives for single FAME (palmitate, stearate, oleate and linoleate methyl esters) ranged between 2.1 and 2.6 days
Ginn et al. (2012)Silty-loam soilSoil slurry with mineral salts mediumGC with mass spectrometry detection; CO2 productionSoybean methyl esters; animal fat methyl esters; ultralow-sulphur diesel, B20 blends, with and without antioxidant (BioExtend containing TBHQ) and biocide additiveCO2 production was observed for a duration of 28 – 30 days, with no CO2 production in the absence of the inoculum (soil); no significant effect of additives on aerobic biodegradation
Vauhkonen et al. (2011)Activated sludge, or groundwaterMineral media, or groundwaterOxygen uptake (OECD 301F test)Rapeseed methyl esters (commercial); rapeseed oilIn 28 days, 60.8% RME and 65.8% rapeseed oil were biodegraded with a sewage sludge inoculum; only 19% RME and 9.9% rapeseed oil biodegraded with groundwater as the inoculum
Elazhari-Ali et al. (2012)Sandy soilWet sandy soil, with and without inorganic nutrients (N, P); oxygenGC of hydrocarbonsB20 made from commercial rapeseed FAME and 12 hydrocarbons blended in the laboratory to resemble gasoline or keroseneToluene was removed at essentially the same rate from the hydrocarbon-only mixture and B20 in the presence of added nutrients, but more rapidly from the hydrocarbon-only mixture (v. B20) in the absence of added inorganic nutrients
Meneghetti et al. (2012)Two soils: clayey soil and sandy soilSoil with and without fertilizerCO2 production; GCVegetable oil methyl esters (source not specified)Reductions of 16.8% in clayey soil and 58.5% in sandy soil were observed by GC in the absence of fertilizer after 110 days; higher percentage reductions were observed in the presence of fertilizer (59.8% in clayey soil and 90.4% in sandy soil; production of CO2 was reported, but appeared to be only a small proportion of the FAME
Yassine et al. (2013a)Culture isolated from aeration tank of wastewater treatment plant and gasoline and triglyceride degrading cultures; acclimated to diesel and FAMEAqueous minimal mineral medium containing vitaminGC/MSCommercial soybean methyl esters; low-sulphur diesel; blends of the above (B20, B40, B60 and B8)Rapid loss initially of FAME from both biotic and abiotic microcosms; biological utilization rates for FAME increased with increasing carbon chain length and decreasing number of double bonds
Yassine et al. (2013b)Culture derived from wastewater activated sludge and gasoline- and triglyceride degrading cultures (acclimated to FAME and FAME–diesel blendsAqueous minimal mineral medium containing vitaminGC/MS; CO2 evolution; biomass productionCommercial soybean methyl esters; low-sulphur diesel; blends of the above (B20, B40, B60 and B80)Rapid loss initially of FAME from both biotic and abiotic microcosm; 64% FAME mineralized within 7 days and 75% within 42 days; C10–C12 alkanes metabolized faster in the presence of FAME
Fuller et al. (2013)Creek waterCreek water; oxygenGC of polyaromatic hydrocarbons (PAH)Tallow and canola oil FAME (10:90 w/w); commercial diesel; B20 blend of the aboveAfter 28 days, a higher proportion of the mass of PAH pyrene, fluoranthene, methylpyrenes, and C2-alkyl fluoranthenes and pyrenes were removed in the B20 blend than in diesel alone
Horel & Schiewer (2014)Cultures isolated from soil and adapted to (1) fish oil alkyl ester (2) Syntroleum, or (3) dieselUnsaturated sandy soil with NPK fertilizer addedCO2 production; microbial enumeration; GC/MSFish oil alkyl ester (ester not specified); diesel; Syntroleum (synthetic oil)Production of CO2 from fish oil alkyl ester lagged behind that from diesel and the synthetic oil even using the inoculum adapted to fish oil alkyl ester; however, maximum CO2 production in 28 days was similar for both diesel and fish oil alkyl ester (<20%)
Lisiecki et al. (2014)Microbial consortium isolated from a crude oil site and enriched on diesel as soil source of carbon; contained Achromobacter, Alcaligenes, Citrobacter, Comamonadaceae, Sphingobacterium, Pseudomonas and VariovoraxMineral salts medium; oxygen, but microcosms were saturated, undisturbed and sealedCO2 production; GC of hydrocarbon fractionsCommercial rapeseed FAME; diesel (EN 590:2004); B10, B20, B30, B40, B50, B60, B70, B80, B90 blends of the above prepared in the laboratoryIn the FAME and diesel microcosms, c. 58 and 30% of FAME and diesel were mineralized to CO2 within 578 days, respectively; the presence of FAME did not appear to enhance the rate or extent of diesel degradation; rates of CO2 production were as predicted by the ratio of FAME to diesel; residual fractions of aromatic and aliphatic hydrocarbons were generally the same in the B10 to B80 microcosms
Thomé et al. (2014)Clayey soilUnsaturated soil with intermittent air flow; no amendmentsWeight per cent of residual hexane-extractable materialB20 blend of commercial soybean alkyl ester (ester not specified) with petroleum dieselAfter 60 days, B20 reductions of up to 85% were observed for the aerated soils and 64% for the unaerated (possibly anoxic) control