The Regulation Of Bacterial Cellulose Biosynthesis And The Fermentation Of Monasus-Bacterial Cellulose Composite

Bacterial Cellulose (BC) is an polysaccharides produced by some microorganisms,which is assembled by some glucan chains. It’s formed with0.9%cellulose,0.3%boundwater and98.8%free water, therefore, it contains a lower solid content which is notdigested by human body, and increases the satiety. Consequently, it can reduce thefood-intake and be used as low calorie diet food. In addition, BC has higher water-holdingcapacity and cation-exchange capacity than plant cellulose, which make it moreeffectively to decreased the concentrations of serum triglyceride, serum total cholesterol,serum low-density lipoprotein. Moreover the fiber can promote bowel movements,dilute the toxins, increase intestinal peristalsis, prevent the occurrence of constipation andcolon cancer, so BC has the great potential applications in the healthy food. Red yeast rice,which is a traditional fermented products grown on japonica rice, rice or glutinous rice byMonascus purpureus. In this paper, BC was modified by adding the water-solublepolysaccharides (e.g. sodium alginate, agar, gum arabic and xanthan gum) to the culturemedium. And monascus-BC composite was fermentated by adding BC into monascussolution. The contents are as follows:1. Different concentrations of sodium alginate, agar, gum arabic and xanthan gumwere added to the fermentation medium of BC respectively, under the conditions of staticculture or dynamic culture at28℃, and then the modified BC films or particles wereproduced. The effects of polysaccharides on BC biosynthesis, morphology and propertieswere studied.2. To make some color on BC and improve it value, we also add BC film into themedium of monascus and were fermented together, so that the red monasus pigment,lovastatin and other physiological activity component can get into the BC.The results shows:1. In the static culture conditions, the viscosity of the growth medium increased bypolysaccharides addition, which hindered the movements of the bacterial, and thetransportation of oxygen and nutrients, so BC yield decreased. The SEM and FTIR resultsshowed that the water-soluble polysaccharide got into the network of BC and combined with the fibers of cellulose. But the structure of BC was reserved, so there weren’t anydifferences on the water-holding capacity and rehydration. However, in the dynamicculture conditions, due to the influence of the shear force, adding different concentrationsof sodium alginate and agar, the different shape of BC particles were produced. Theparticles can be suspended in aqueous solution under the certain concentrations, whichmake it very suitable for food and beverage application.2. BC films were added into the medium of monascus, thus the monasus-BCcomposite was produced. This composite had a good color stability under the condition ofautoclaving or frozen. The SEM results showed that Monascus mycelium penetrated theempty space of bacterial cellulose network and could grow well with the structural of BC,so the network of BC was very suitable for the growth of the monascus. This provided atheory that BC can be a supportive carrier for growth of other microorganisms.