Kinetics of Phosphate Ions and Phytase Activity Production for Lactic Acid-Producing Bacteria Utilizing Milling and Whitening Stages Rice Bran as Biopolymer Substrates.

A study evaluated nine kinetic data and four kinetic parameters related to growth, production of various phytase activities (PE act ), and released phosphate ion concentration ([Pi]) from five lactic acid bacteria (LAB) strains cultivated in three types of media: phytate (IP6), milling stage rice bran (MsRB), and whitening stage rice bran (WsRB). Score ranking techniques were used, combining these kinetic data and parameters to select the most suitable LAB strain for each medium across three cultivation time periods (24, 48, and 72 h). In the IP6 medium, Lacticaseibacillus casei TISTR 1500 exhibited statistically significant highest ( p ≤ 0.05) normalized summation scores using a 2:1 weighting between kinetic and parameter data sets. This strain also had the statistically highest levels ( p ≤ 0.05) of produced phosphate ion concentration ([Pi]) (0.55 g/L) at 72 h and produced extracellular specific phytase activity (ExSp-PE act ) (0.278 U/mg protein ) at 48 h. For the MsRB and WsRB media, Lactiplantibacillus plantarum TISTR 877 performed exceptionally well after 72 h of cultivation. It produced ([Pi], ExSp-PE act ) pairs of (0.53 g/L, 0.0790 U/mg protein ) in MsRB and (0.85 g/L, 0.0593 U/mg protein ) in WsRB, respectively. Overall, these findings indicate the most promising LAB strains for each medium and cultivation time based on their ability to produce phosphate ions and extracellular specific phytase activity. The selection process utilized a combination of kinetic data and parameter analysis.