A two step process for production of omega 3-polyunsaturated fatty acid concentrates from sardine oil using Cryptococcus sp. MTCC 5455 lipase

• A two step process developed for PUFA concentrates using Cryptococcus sp. lipase.
• Lipase activity was 60 U/mL at 72 h and 25 °C in a 3.7 L fermenter.
• Hydrolysis of various fish oils by the lipase were evaluated.
• Urea complexation of the hydrolysed sardine oil enriched PUFA content to 72.1%.
• A mixture of enriched PUFA containing 44.3% EPA and 11.6% DHA was obtained.

The omega-3 polyunsaturated fatty acid concentrates rich in eicosapentaeonic acid (EPA) and docosahexaenoic acid (DHA) were prepared by a two-step process involving the hydrolysis of sardine oil using lipase obtained from Cryptococcus sp. MTCC 5455 followed by urea complexation. The lipase was produced in a 3.7 L fermenter with an agitator speed of 300 rpm and airflow rate of 1 vvm at 25 °C. A maximum activity of 60 ± 2 U/mL and a productivity of 0.8 U/mL/h was obtained at 72 h, which was 1.6 times greater than at shake flask level. The concentrated enzyme could hydrolyse sardine oil effectively and the reaction conditions were optimized by central composite rotatable design. A hydrolysis ratio of 83.7% was obtained at 72 h with 1000 U of lipase and 1% (w/v) Triton X-100 concentration. Urea complexation of the hydrolysed sardine oil enriched the contents of EPA and DHA to 44.3% and 11.6%, which were 2.6 and 1.8 times higher than the initial content of the oil. Spectral properties of the enriched PUFA concentrates were evaluated by ATR-FTIR and 1H NMR spectroscopy. PUFA enrichment using native lipase from yeast Cryptococcus sp. was attempted for the first time in this study.

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