Screening of Fatty Acid Production by Bifidobacterium lactis in Soybean Cakes

Microbial fermentation using solid substrates offers a safe, cost-effective straightforward approach for generating valuable organic acids, constituting the third-tier product category in addition to enzymes and secondary metabolites. This study investigated potentials of soybean meal paste as a substrate without the need of additional supplements, with the specific aim of propagating probiotic cultures and assessing performance of Bifidobacterium lactis in fatty acid production.

A homogenized soybean meal paste was prepared with an initial moisture content of 65% to begin solid-bed fermentation. This paste was inoculated with 4% of microbial culture and then incubated at 37 °C.

After 24 h of fermentation, strain showed significant acidification and increases in cell numbers. Moreover, the microorganism demonstrated significant capacity to modulate levels of saturated and unsaturated fatty acids within the media, in contrast to the control media. The fatty acid composition shifted to a higher proportion of saturated fatty acids as well as further decreases in omega-3 acid than omega-6 fatty acid. Inoculation of the bacteria at 4% with substrate fermentation led to significant increases in the microbial population to 9.98 log CFU/g and decreases in pH levels to 5.1 at the optimal temperature of 37 °C.

The soybean paste demonstrates potentials as a carrier for this probiotic microorganisms, facilitating fatty acid production. This microorganism enhanced nutritional and functional characteristics of the substrate, rendering soybean meal an appealing option for the production of innovative products for market consumers. The findings suggest promising solutions for the cost-effective and sustainable production of organic acids and fatty acids using solid substrates and probiotic microorganisms.