Overproduction of a potential red pigment by a specific self-immobilization biomembrane-surface liquid culture of Penicillium novae-zeelandiae.

A specific self-immobilization biomembrane-surface liquid culture (SIBSLC) was developed to overproduce a potential penicillium red pigment. Statistic analysis shows that both glucose concentration and membrane diameter are important factors influencing the yield of red pigment. After the optimization using central composite experimental design, the maximum yield of red pigment in shake flask reaches 4.25 g/l. The growth of strain HSD07B consists of three phases, and the pigment secreted in the decelerated phase, is originated from the interior of biomembrane where glucose exhaustion occurs. In addition, the batch and continuous SIBSLC were conducted for production of the pigment, and the latter was more competitive in consideration of the fact that it not only increased 61.5 % of pigment productivity, but also simplified the production process. Moreover, the pigment produced by SIBSLC is potentially acceptable for food applications although it is distinguished from the co-cultured red pigment we reported previously in components.

Improvement of the production of a red pigment in Penicillium sp. HSD07B synthesized during co-culture with Candida tropicalis.

Co-culture of Penicillium sp. HSD07B and Candida tropicalis resulted in the production of a red pigment consisting of six components as determined by TLC and HPLC. The pigment showed no acute toxicity in mice and was mot mutagenic in the Ames test. The pigment was stable between pH 2 and 10 and temperatures of 10-100°C and exhibited good photo-stability and resistance to oxidization by hydrogen peroxide and reduction by Na(2)SO(3). Glucose and ratio of C. tropicalis to strain HSD07B (w/w) in the inoculum were the important factors influencing production of the pigment. Under optimized conditions, a pigment yield of 2.75 and 7.7 g/l was obtained in a shake-flask and a 15 l bioreactor, respectively. Thus, co-culture of strain HSD07B and C. tropicalis is a promising way to produce a red pigment potentially useful for coloring applications.