Study of Canola Meal Extract in the Synthesis of Lipids by Mortierella alpina

Abstract

Quality and cost-effective raw materials and the utilization of agriculture by-products with potential quality attributes and negligible commercial value can be supplemented in several microbial processing industries. Canola meal (CM), a by-product of canola processing, has an excellent nutritional profile composed of protein, carbohydrates, vitamins, and minerals, and could serve as a potential candidate for microbial culture media. Saskatchewan, as a global leader in canola production, has plans for upscaling its canola processing facilities. The efficient utilization of canola meal extract (CME) in the production of lipids and polyunsaturated fatty acids, such as arachidonic acid (ARA) has the potential to serve as valuable ingredients or base chemicals for food, feed, and nutraceutical industries. This current study focused on the incorporation of alkaline extract (AE) and subcritical extract (SE) of CM in a culture medium of an oleaginous fungus, Mortierella alpina ATCC 32223, by replacing conventional yeast extract (YE) at a level of 50 % and 100 %. Extraction for AE was conducted at 75 °C with a pH of 10.5, while for SE, it was carried out at 160 °C without pH control. Initial trials were conducted to examine the effect of aeration at a level of 0.5 to 2.0 vvm on fungal growth and it was found that increasing aeration rate increased fungal growth rate from 0.16 day-1 to 0.39 day-1. Also, the ARA percentage in the lipid increased from 10.39% to 21.86%. It became evident that ARA production was positively correlated with biomass accumulation and its lipid content. During the replacement of YE by CME, it was observed that the 100% substitution of YE by CME yielded growth results similar to that of the control, which employed standard media containing YE. Moreover, AE- and SE-supplemented media exhibited a higher ARA accumulation of 144.91 mg/L and 165.8 mg/L, respectively, in comparison to standard media (124.87 mg/L). Interestingly, when glucose was omitted from the culture, media supplemented with 100% AE performed better as compared to standard media. However, the limitation of glucose had an adverse effect on both the growth and lipid content of the culture