Screening of phytase producing lactic acid bacteria and their application todecrease phytic acid in jack beans (Canavalia ensiformis)

Phytase (myo-inositol hexakis-phosphate phosphohydrolase) is an enzyme capable of hydrolyzing phytic acid (PA). The hydrolysis of PA by phytase leads to an increase in the bioavailability of the minerals for humans or animals. Lactic acid bacteria (LAB) are considered safe phytase producers for further applications. Nevertheless, the best candidate for phytase-producing LAB remains to be explored. Lactiplantibacillus plantarum IIA-1A5, Lactobacillus acidophilus IIA-2B4, Enterococcus faecium IIA-2D2, and Pediococcus pentosaceous IIA-2A2 were LAB isolated from the meat of Peranakan Ongole cattle, which were proven to be excellent fermentation starters. Nevertheless, the ability of these LAB to produce phytase has never been investigated. This study aimed to determine the production and activity of phytase from these LAB and apply the LAB with the phytase activity in the fermentation of jack beans (Canavalia ensiformis) to measure the phytic acid degradation. The phytase activity was then assayed spectrophotometrically using the Phytase Assay Kit (K-PHYTASE) method, which revealed that only L. plantarum IIA-1A5 and L. acidophilus IIA-2B4 strains exhibited detectable phytase activity of 20 and 60 mU/mL, respectively. No phytase activity was detected for E. faecium IIA-2D2 and P. pentosaceous IIA-2A2. Furthermore, L. plantarum IIA-1A5 and L. acidophilus IIA-2B4 have been shown to be able to decrease phytic acid levels in jack beans from 6.3 g/100 mL to 2.4 g/100 mL (L. plantarum IIA-1A5) and 3.6 g /100 mL (L. acidophilus IIA-2B4). Altogether, these results demonstrated that L. plantarum IIA-1A5 is better as a novel phytase-producing LAB than L. acidophilus IIA-2B4.