Utilization of microbial oil obtained from crude glycerol for the production of polyol and its subsequent conversion to polyurethane foams

•Crude glycerol was converted to microbial oil using a robust oleaginous yeast.•Microbial oil was chemically converted to polyol.•Suitability of obtained polyols for polyurethane production demonstrated.•Carbon present in glycerol waste fixed via polyurethane formation.

We have demonstrated possible use of microbial oil in biopolymer industries. Microbial oil was produced from biodiesel based crude glycerol and subsequently converted into polyol. Fermentation of crude glycerol in a batch bioreactor using Rhodosporidium toruloides ATCC 10788 produced 18.69 g/L of lipid at the end of 7 days. The microbial oil was then chemically converted to polyol and characterized using FT-IR and 1H NMR. For comparison, canola oil and palm oil were also converted into their respective polyols. The hydroxyl numbers of polyols from canola, palm and microbial oil were found to be 266.86, 222.32 and 230.30 (mg KOH/g of sample) respectively. All the polyols were further converted into rigid and semi-rigid polyurethanes (maintaining the molar -NCO/-OH ratio of 1.1) to examine their suitability in polymer applications. Conversion of microbial lipid to polyurethane foam also provides a new route for the production of polymers using biodiesel based crude glycerol.

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