Modified rotary biofilm reactor: A new tool for enhanced carotene productivity by Blakeslea trispora

Abstract

The objective of this study was to build up a modified rotary biofilm reactor (MRBR) and to evaluate it as a fermentation system for carotene production by the fungus Blakeslea trispora. In this system, the discs are adjoined to the medium, and the air is introduced into the substrate by an air pump through a silicone tube in order to spray the medium on the discs of the reactor. The microorganism is grown on the discs forming a biofilm, which is stable until the end of fermentation. The major advantage of this reactor is the maximum carotene concentration, which is achieved in a short fermentation time, resulting in high carotene productivity. The maximum carotene productivity (57.5 mg/L/day) was obtained in a culture grown in 1 L of the synthetic medium with an initial pΗ of 11.0, an aeration rate of 4 vvm, an inoculum ratio 1:5 of (+) and (−) strain of B. trispora and the discs rotating at 13 rpm. The carotene productivity in the MRBR was six times higher compared to that obtained in the conventional stirred tank reactor (STR). The results, along with the advantages of the MRBR, show that the suggested fermentation system can be used for carotene production by B. trispora in industrial scale.