Effect of Carbon Sources on Different Strains of Phytase-Producing Bacteria Isolated from Malaysia’s Hot Spring

Abstract

Animal feed from cereal grains and oilseed meals mainly containing phytic acid which has adverse effects on animal nutrition and its environment. Ruminants can easily digest the phytic acid as they have fungi and bacteria in their guts which can produce phytase to degrade the phytic acid. Meanwhile, phytic acid in non-ruminant animals is poorly digested due to the lack of sufficient phytase in their guts. Thus, the feed must be supplemented with inorganic phosphate to ensure it can absorb adequate nutrients. This study aimed to determine the effects of using different carbon sources to the growth of different strains of phytase producing bacteria based on optical density (OD), colony forming unit (CFU), and their phytase production. All four strains of potentially producing-phytase bacteria have been isolated from several hot springs in Malaysia. The bacteria were grown in modified Phytase Screening Medium (PSM) with glucose and lactose as a carbon source and under optimum culture conditions (pH 5.5, 37˚C, 200 rpm) for 72 hours. For quantitative screening of phytase production, the bacterial cultures were harvested to obtain the supernatants that were used to measure the amount of inorganic phosphorus released by the bacterial strains. Among these carbon sources, glucose has shown consistency between their CFU counts and the observed ODs whereas lactose shown inconsistency. Meanwhile, the maximum phytase activity was recorded for all strains in the presence of glucose in which bacteria strain L3 (0.0404 U/mL), RT (0.0359 U/mL), B9 (0.0262 U/mL), and A (0.0263 U/mL). As for the overall, strain L3 (Labis, Johor) gave a promising rate of inorganic phosphate released with optimum phytase activity value of 0.0404 U/mL in presence of glucose and lactose. The optimisation of the fermentation medium can contribute to more economical production of industrial enzyme as phytase has the potential to produce feed additives for poultry feeding.