Valorisation of untreated cane molasses for enhanced phytase production by Bacillus subtilis K46b and its potential role in dephytinisation.

BACKGROUND: The high cost of phytase production is the most limiting factor in its application in animal feeds. The present study aimed to develop a low-cost medium for production of a novel phytase in submerged fermentation using inexpensive agro-industrial by-products. The applicability of phytase in dephytinisation of commonly used food/feed ingredients, i.e. soybean meal and wheat bran, was also investigated. RESULTS: Using a one-factor-at-a-time approach, soybean meal and cane molasses were identified as significant agro-industrial by-products and these factors were subsequently optimised using response surface methodology (RSM). A central composite design was employed to further enhance phytase yield. Under optimum conditions of soybean meal 22.3 g L-1 , cane molasses 100 g L-1 and 39 h fermentation, phytase production increased to 56.562 U mL-1 , indicating more than 28-fold enhancement. The enzyme efficiently dephytinised wheat bran and soybean meal after 24 h incubation at 56.5 °C and increased inorganic phosphate content by 240% and 155%, respectively. CONCLUSION: Soybean meal and cane molasses were successfully used for enhancement of phytase production as economical carbon, nitrogen and phytic acid sources using RSM. The phytase showed a good capability to dephytinise wheat bran and soybean meal, demonstrating that the enzyme can be considered as a potential candidate for industrial food and feed applications. © 2016 Society of Chemical Industry.

A novel phytase characterized by thermostability and high pH tolerance from rice phyllosphere isolated Bacillus subtilis B.S.46.

In this study, an extracellular alkali-thermostable phytase producing bacteria, Bacillus subtilis B.S.46, were isolated and molecularly identified using 16S rRNA sequencing. Response surface methodology was applied to study the interaction effects of assay conditions to obtain optimum value for maximizing phytase activity. The optimization resulted in 137% (4.627 U/mL) increase in phytase activity under optimum condition (56.5 °C, pH 7.30 and 2.05 mM sodium phytate). The enzyme also showed 60-73% of maximum activity at wide ranges of temperature (47-68 °C), pH (6.3-8.0) and phytate concentration (1.40-2.50 mM). The partially purified phytase demonstrated high stability over a wide range of pH (6.0-10.0) after 24 h, retaining 85% of its initial activity at pH 6 and even interestingly, the phytase activity enhanced at pH 8.0-10.0. It also exhibited thermostability, retaining about 60% of its original activity after 2 h at 60 °C. Cations such as Ca(2+) and Li(+) enhanced the phytase activity by 10-46% at 1 mM concentration. The phytase activity was completely inhibited by Cu(2+), Mg(2+), Fe(2+), Zn(2+), Hg(2+) and Mn(2+) and the inhibition was in a dose dependent manner. B. subtilis B.S.46 phytase had interesting characteristics to be considered as animal feed additive, dephytinization of food ingredients, and bioremediation of phosphorous pollution in the environment.