Evaluation Of Anovel Bio-reactor For Bacterial Cellulose Production

Bacterial cellulose (BC) is a kind of biodegradable natural nano-structured cellulose, whichis produced by microorganisms. Bacterial cellulose has unique physical and chemical properties.It has been hot topics in the field of biological materials all over the world in recent years.Bacterial cellulose has been widely used in food and beverage industry and has great potential inspecial paper industry, oil exploitation, biomedical materials and other fields. The main problemof bacterial cellulose is its low efficiency in production. It couldn’t be produced in largequantities. We need to develop efficient bioreactors and to search for productive strains in orderto improve production.Fermentation reactors for bacterial cellulose production at present have two kinds. One isshallow dish reactor, the other is stirred tank reactor. In industrial production, reactor willdirectly affect the yield of bacterial cellulose. A proper reactor is very important for industrialproduction. On the one hand it should meet the requirement for rapid growth of the strain, on theother hand, the reactor should take the production of cellulose into account. By changing thefermentation tank’s design such as the shape of a container and a stirring paddle, can get idealcellulose products. Researchers are using different methods to improve the reactor. This articleused a new type of bioreactor, which works through a low speed drum furnished by gauze. Thereactor built a dynamic environment, which was designed on the basis of the physiological habitsof bacteria. The reactor could improve the oxygen transfer rate and could avoid negative effectsof high shear force on the growth of strain. This reactor improved the production efficiency ofBC. This subject will make further study of the reactor to improve cellulose production so as to provide a reference for the industrial production. This subject compared three different culturingmethods under same condition to analyze the potentiality of this reactor.Acetobacter xylinum could produce the largest quantities of BC. Nearly all factory use it.Our laboratory has several modified A. xylinus strains. We used these strains to select the mostproductive strain in the reactor and compared the properties of BC. The cellulose obtained bydifferent culturing methods was analyzed by scanning electron microscope observation. Andmoisture content, water retention properties and tensile strength of the BC were also compared.The result showed that the production efficient of drum rector up to82.5mg L-1h-1washigher than shallow dish reactor35.9mg L-1h-1and stirred tank reactor55.7mg L-1h-1. The shapeof cellulose produced by the stirred tank reactor is irregular. The production of the drum reactorhave the Young modulus of1040MPa close to shallow dish reactor’s1300MPa.DHU-ZGD-1gained the highest production in the novel reactor of25.3g L-1under4%sugar rate about20%higher than the second one. The production rate have reached150.6mgL-1h-1. The cellulose of this strain had the best mechanical properties compared with other strainsthe Young modulus have reached1150MPa. The maximum tensile strength reached50MPa,50%higher than other strains. It’s the suitable strain for the reactor.This novel reactor used in the study is a simple prototype. Its sealing and use couldn’t meetthe requirement of industrial production. We intend to enlarge the reactor model, and design a30L stainless steel tank out of the reactor. We try to make improvements for the reactor for futureindustry production.