Effect of pH modification on bilge waste biodegradation by a native microbial community

Biodegradation pattern of hydrocarbons from a fuel oil-type complex residue by an emulsifier-producing microbial consortium

“…However, R 2 decreased to values lower to 0.65 (n = 14, p < 0.05) for both experiments when data of the whole duration of the assays were correlated. This fact indicated that the observed sharp turbidity increases could not be associated with microbial growth, suggesting that hydrocarbons emulsification could be responsible of them, as it was found in a previous study where the same microbial consortium was used [20]. Furthermore, the final turbidity values (16 and 5 AU for the high and the low initial BWOP concentrations, Figs.…”

“…The floating organic phase named bilge waste oily phase (BWOP), a partially weathered fuel oil-type residue, was previously physically and chemically characterized [18][19][20]. Hydrocarbon analyses were performed by dissolving BWOP in n-hexane and treating with silica gel (see more detail in Section 2.4).…”

“…Hydrocarbon analyses were performed by dissolving BWOP in n-hexane and treating with silica gel (see more detail in Section 2.4). BWOP was also fractioned in alumina column to quantified aliphatic and aromatic hydrocarbons [20]. Hydrocarbon-concentrations found by GC analysis were (expressed as g kg −1 BWOP): total hydrocarbons (TH), 542 (being 89% aliphatics and 11% aromatics); resolved TH (RTH), 136; and UCM, 406.…”

“…A microbial consortium was obtained by an enrichment procedure, using a mineral medium and 1% (v/v) BWOP as the only carbon and energy source [20]. The consortium, whose emulsifier production capacity was previously tested [20], was mechanically stirred using an orbital shaker (160 rpm) at 25 • C. Cultures were transferred twice a week in fresh liquid medium (1%, v/v) and then incubated in the same conditions. Inoculums used in the present study were prepared with a 48-h culture by washing and resuspending the cell at OD 450 = 0.1 [20].…”

“…The consortium, whose emulsifier production capacity was previously tested [20], was mechanically stirred using an orbital shaker (160 rpm) at 25 • C. Cultures were transferred twice a week in fresh liquid medium (1%, v/v) and then incubated in the same conditions. Inoculums used in the present study were prepared with a 48-h culture by washing and resuspending the cell at OD 450 = 0.1 [20]. Consortia used as inoculums were at least 10 transfers old since the start of the enrichment procedure.…”