Table 5.

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

ReferenceSource of inoculumMediaMeasurementFAME and other substratesReported results
Stolz et al. (1995)Pond or lake water; topsoil; culture grown on soybean FAMEMineral salt medium; nitrate as electron acceptorGC; methanol (by Draeger tubes); nitriteSoybean FAME100% removal of FAME (as measured by GC) was observed in 14 days in anaerobic microcosms compared with about 50% in the uninoculated controls; 100% removal was observed in 7 days in parallel aerobic microcosms; the denitrifying bacterium H1 (B. solanocearum) was isolated using soybean FAME as the soil source of carbon
Cyplik et al. (2010)Microbial consortium isolated from crude oil site under aerobic conditions containing Achromobacter, Alcaligenes, Citrobacter, Comamonadaceae, Sphingobacterium, Pseudomonas and VariovoraxMineral salt medium, pH 7; nitrate as electron acceptorNitrate and nitrite; GCCommercial rapeseed FAME; commercial diesel20% removal of FAME v. 5% removal of diesel within 5 days, with 100% removal of FAME over the same period in parallel aerobic microcosms; nitrate depletion and nitrite production was observed; the microbial community structure was similar when grown on FAME or diesel
Corseuil et al. (2011)Groundwater and sediments (unacclimated to FAME)Groundwater and sediments; nitrate and sulphate as electron acceptorsGC; nitrate and sulphateFAME from soybean oil and castor oil (from Paraná Institute of Technology)Rate and extent of soybean oil FAME removal was greater than for castor oil FAME; stearate (C18:0) disappeared more slowly from soybean FAME than the other C16 and C16 FAME; sequential depletion of nitrate followed by sulphate was observed with soybean oil FAME; however, only nitrate was depleted with castor oil FAME
Adair & Wilson (2009, 2010a,b)Sediments from jet fuel release site; sediments from a biodiesel release siteUnspecified; with or without sulphate as electron acceptorMethaneBiodiesel (unspecified)Conversion of 3 mg biodiesel l−1 to methane was observed per day; the rate was similar in the presence and absence of sulphate
Aktas et al. (2010)Anaerobic cultures: (1) hydrocarbon degradation under sulphate and methanogenic conditions from contaminated aquifer sediments at natural gas field; (2) alkane-degrading methanogenic culture from contaminated aquifer sediments at natural gas field; (3) marine oil degrading sulphate-reducing culture from sunken ship; (4) culture from seawater ballast tank; none, except possibly (4), were acclimated to FAMESeawater or freshwater with CO2/N2 headspace; sulphate as electron acceptor followed by methanogenesis after sulphate depletionSulphate reduction; methane production; GCSoybean FAMEIn the presence of FAME, sulphate was consumed by three of the inocula within 1 month with methane produced by two of the inocula; FAME was converted to free fatty acids ranging in chain length from C6 to 24 in the inoculated microcosms, whereas in the sterile controls only C16–C24 FAME were observed; the detection of the shorter chain length fatty acids was consistent with β-oxidation; sulphate reduction was observed
Borges et al. (2014)Lagoon sediments; (unacclimated to FAME)Mineral salt medium; sulphate as electron acceptorMethane production; benzene by GCLaboratory-produced FAME from soybean oil, castor oil and pork lardMethane production was observed within about 40 days in all live microcosms and reached maximum methane production within 150 – 200 days; rates of methane production were similar among all three FAME (soybean, pork and castor); short-chain acids (acetate, propionate, formate, pyruvate and malonate) were detected with malonate the predominant acid in all three FAME microcosms
Sørensen et al. (2011)Water obtained in summer or winter from a light diesel storage tank diluted to c. 106 cells ml−1Water from diesel tank; limited nitrate and sulphateMethane production; biomass productionCommercial animal fat (pork lard) FAME; commercial fossil dieselWhen water obtained during the summer was used as inocula, methane production was observed to occur for 13 days in the presence of FAME and blends of FAME with diesel (B5, B10, B20, B50), but not with diesel; a five-fold increase in biomass was also measured; no methane production was observed when water obtained during the winter was used as inocula