Enhancement of mycelial growth and polysaccharide production in Ganoderma lucidum (the Chinese medicinal fungus, `Lingzhi') by the addition of ethanol
Methanol, ethanol, 1-propanol and 2-propanol, at 1.5% (v/v), enhanced the growth and polysaccharide production of Ganoderma lucidum. Ethanol was the most effective at 1.5% (v/v) for increasing the biomass production, however, the maximal polysaccharide concentration was produced with 2% (v/v) ethanol in the medium. There was no new polysaccharide component produced by the addition of ethanol.
Exopolysaccharide biosynthesis and related enzyme activities of the medicinal fungus, Ganoderma lucidum, grown on lactose in a bioreactor
Exopolysaccharide (EPS) production and biosynthesis were studied in Ganoderma lucidum, a fungus used in traditional Chinese medicine, grown with lactose in a bioreactor. β-Galactosidase activity, which implies the existence of a lactose permease system, was induced by lactose. Lactose feeding also increased α-phosphoglucomutase activity and EPS accumulation but decreased phosphoglucose isomerase activity and lactate concentration in the culture broth. A maximum cell density of 22 g l−1 and EPS at 1.25 g l−1 were obtained in fed-batch bioreactor culture.
Bistage control of pH for improving exopolysaccharide production from mycelia of Ganoderma lucidum in an air-lift fermentor.
It was found that pH control definitely affects mycelial cell growth and exopolysaccharide (EPS) production of the mycelial cultivation of Ganoderma lucidum. Compared to the case of uncontrolled pH cultivation, a culture system whose pH was kept constant at 3 and 6 exhibited improved mycelial cell growth and EPS production, respectively. The bistage pH control technique, that is, shifting the pH from 3 to 6 at the initial phase of the exponential growth, is introduced to improve cell growth and EPS production. This technique can greatly increase EPS production to 20.1 g/l from 4.1 g/l in the case of uncontrolled pH cultivation, without adverse effects on cell growth as in the case of constant maintenance of a high pH. It was also proved that bistage pH control retained the desirable morphologies of the mycelia during cultivation and resulted in low viscosity and yield stress of the culture broth. It will be useful for the application of the culture process to mycelial growth in a large-scale fermentor.