Lipid production by eukaryotic microorganisms isolated from palm oil mill effluent

• Palm oil mill effluent (POME) contained microorganisms able to accumulate lipids.
• Community composition of the organisms enriched from POME was analyzed.
• Graphium penicilloides isolated from POME contained more than 20 wt% lipids.

Microbial oil production combined with wastewater management is one option for a more sustainable future. Micrographs of microbial cultures enriched from palm oil mill effluent (POME) showed lipid inclusion in the eukaryotic cells, indicating the cells can accumulate lipids. However, enriching the culture did not increase the total lipids. Therefore, eukaryotic microorganisms were isolated from POME to investigate whether these microorganisms are potential lipid producers. Four strains were isolated, and their lipid synthesis capabilities were compared with known oleaginous yeasts in a synthetic oil-free medium. Two strains (identified as Galactomyces geotrichum and Graphium penicillioides) had the potential to accumulate lipid accumulation based on the increase in triacylglycerol content. G. penicillioides was the most promising strain for lipid production as this strain accumulated more lipids than the well-known oleaginous yeast Cryptococcus curvatus (29.1 ± 3.0 wt% vs. 20.2 ± 2.9 wt%). To our knowledge, oil synthesis and accumulation by G. penicillioides have not previously been reported.