Development of a Menaquinone-7 enriched product through the solid-state fermentation of Bacillus licheniformis

Abstract

Bone fracture is a significantly prevalent issue in both large and small animals, in particular cats, dogs, and horses. Recent studies have shown that adequate consumption of the vitamin Menaquinone-7 (MK-7) has the ability to reduce the incidence of bone fractures, by increasing the bone mineral density. Therefore, the development of an MK-7 enriched animal feed poses as a promising concept that is likely to significantly benefit the health and wellbeing of animals, and improve their quality of life. The aim of this investigation was to build on the different aspects of previously conducted studies, and apply the relevant findings and experimental procedures to enhance the production of MK-7 through the solid-state fermentation of Bacillus licheniformis, for the unique application of an MK-7 enriched animal feed, in order to limit the incidence of bone fractures in animals. An optimisation study was performed using composite face-centered experimental design. The most ideal combination of the experimental variables for the biosynthesis of MK-7 was determined to be 10% (w/w) tryptone, 20% (w/w) glucose, and 2% (w/w) K2HPO4, when the soybean substrate is inoculated with 5% (v/w) of B. licheniformis and incubated at a temperature of 32 °C, for a fermentation period of 72 hours. The optimisation process was then validated and the highest concentration of MK-7 (12.507 mg/kg) that was obtained was fairly similar to the value predicted by the model. The results and observations from this research are a valuable step towards achieving a better understanding of the ability of feed grade bacterial cultures to enhance the production of MK-7 through solid-state fermentation for the development of functional animal feed in the future.