Biofortification of Indian rice (IR-532-E-576) with monacolin K by RSM optimisation using Monascus purpureus MTCC 1090

Abstract

The present study demonstrates that the monacolin K concentration of Monascus-fermented rice can be increased by proper optimisation of fermentation parameters using a Box-Behnken experimental design. The monacolin K level was increased by up to 10% in a response surface method (RSM)-optimised medium composition as compared to a composition optimised using a classical method. The effect of nutritional factors such as substrate sources, carbon sources, nitrogen sources and inducers on monacolin K production was studied using Monascus purpureus MTCC 1090 in solid-state fermentation using Indian rice as the substrate. Other fermentation parameters like pH, temperature and particle size of substrate were also optimised using the ‘one-factorat-a-time’ classical method. The concentrations of most significant factors and their interactions were studied using RSM. The optimal medium components for enhanced monacolin K production were found to be fructose, 2.14% (w/w); sodium nitrate, 0.16% (w/w); acetic acid, 0.60% (v/w) at pH 5, temperature 30°C and particle size of selected substrate (IR-532-E-576 rice) 2 mm. A maximum monacolin K fortification of up to 37.002 μg/ml was obtained under the optimised conditions.