Production of phytase from Lactobacillus paracasei strain and its probiotic profile

ABSTRACT

Phytase, as an effective enzyme for phytic acid degradation, has significance in bioremediation, poultry and aquaculture. In view of such an environmental and industrial importance, phytase producing probiotic bacteria have gained attention. Here, we screened lactic acid bacteria (LAB) for their phytase producing potential. The strain showing maximum phytase activity was studied for its probiotic characteristics. Among 20 LAB isolated from Kalarei, an edible source, two isolates K.J (a) and K exhibiting maximum enzyme activity (5.18 U/mL and 5.0 U/mL) were selected. In optimization studies for production of phytase using ‘one-variable-at-a-time’ (OVAT) approach, isolate K showed maximum (5.92 U/mL) enzyme activity. The strain was identified by ribotyping as Lactobacillus paracasei and the sequence was submitted in NCBI GenBank under accession number MK280749. Further optimization studies for phytase production were carried out using Plackett–Burman design and central composite design (CCD) of response surface methodology (RSM). Statistically optimized four significant variables incubation temperature, initial pH, maltose and peptone resulted in an increase (6.37 U/mL) in enzyme activity. The enzyme was purified 3.97 fold with a specific activity of 278 U/mg.The molecular weight of enzyme was 70 kDa and optimum activity was determined at 37°C, pH 5.5. The strain was designated as Lactobacillus paracasei SMVDUDB1 and showed promising probiotic characteristics viz. survival rate above 80% (low pH, high bile salt concentration under simulated gastrointestinal conditions), hydrophobicity with chloroform (96.74%), autoaggregation (69.61%) and coaggregation ability (82.79%) with Bacillus subtilis.