The effect of fermentation conditions (temperature, salt concentration, and pH) with lactobacillus strains for producing Short Chain Fatty Acids

Abstract

Short-Chain Fatty Acids are one of the vital metabolites generated by the fermentation of dietary fiber in the gastrointestinal tract through bacterial fermentation and play an essential role in human health. This a study aimed to evaluate the effects of different fermentation conditions, including temperature (30, 42 °C), salt concentrations (2, 4 and 6%), pH (4.5, 5 and 6), and their interaction effects on the production of short-chain fatty acids (acetic acid, propionic acid, isobutyric acid, butyric acid, isovaleric acid, valeric acid) by Lactobacillus fermentum ATCC 9338, Lactobacillus fermentum 19SH and Lactobacillus acidophilus ATCC 4356. Once grown under different fermentation conditions, supernatants and pellets of fermentation media were separated, and then SCFAs were measured using Gas chromatography/mass spectrometry (GC-MS). Results revealed that fatty acid content was altered in each fermentation condition, and the highest amount after lactic acid belonged to propionic acid. Accordingly, Lb. Fermentum 19sh, Lb. Fermentum ATCC9938, and Lb. Acidophilus ATCC4356 produced the highest levels of isovaleric acid, acetic acid, propionic acid, isobutyric acid, butyric acid, and valeric acids, respectively. The results indicated a relationship between the production of short-chain fatty acids and the growth of bacterial strains and cell membrane characteristics.