Studies on the reduction of organic load from palm oil mill effluent (POME) by bacterial strains

Introduction Palm oil mill effluent (POME) containslarge quantities of organic matter in the form of total suspendedsolids (TSS), volatile suspended solids (VSS), totalsolids (TS), oil and grease (O & G) that increase biochemicaloxygen demand (BOD) and chemical oxygendemand (COD) of POME if left untreated. The main aim ofthe present study was to investigate the ability of bacterialstrains either pure (individually) or mixed (combinations),to degrade and metabolize organic load from palm oil milleffluent.Results Sequencing of the 16S rRNA of the isolatessuggests that they were identified as Micrococcus luteus101 PB, Stenotrophomonas maltophilia 102 PB, Bacilluscereus 103 PB, Providencia vermicola 104 PB, Klebsiellapneumoniae 105 PB and Bacillus subtilis 106 PB. The useof mixed cultures in the present study showed moreextensive removal of organic load (COD and BOD) thanpure single cultures. Mixed cultures were found to reducethe pollutant dynamically. Thus, the mixed cultures C1(Bacillus cereus 103 PB and Bacillus subtilis 106 PB)were the most effective bacterial combination for use inbiological treatment technology of POME having thehighest COD and BOD reduction rate. C1 produced thehighest degradative activity in reducing COD (90.64 %)and BOD (93.11 %).Conclusion The indigenous microbial isolates fromPOME were observed to possess potential to degradeorganic components whereas the use of mixed culturesresulted in more extensive degradation of COD and BODthan pure single cultures. This suggests that mixed cultureof bacteria in the present study can be used for bioremediationof environment contaminated with polluted wastewaters.This study, however, indicates the prospect ofisolating indigenous microorganisms in the POME foreffective biotreatment of POME.