Optimization Of Synthesis Of Bacterial Cellulose In Kombucha By Response Surface Methodology

Kombucha is a kind of folk acid health drink with many beneficial effects to humanhealth. Because of its fragrance, simple making and a variety of health functions,Kombucha has been very popular with people of all ages. There is usually a film floating atthe surface of Kombucha liquid when cultured statically. The film was synthesized byGluconacetobacter spp with the help of yeast strains. The film makes up with bacterialcellulose (BC).Bacterial cellulose (BC) is also by the name of Microbial Cellulose that is a naturalPolymer synthesized by bacteria. From the cellulose composition, BC is a linearcondensation Polymer consisting of D-anhydroglucopyranose units (glucose unit forconvenience) joined together by B-l,4-glycosidic bonds (thus a l,4-β-D glucan) like plantcellulose. While to physical, chemistry and mechanical properties, it displays uniqueproperties including high crystallinity, high water holding capacity, nanofibre-networkstructure, high tensiles trength and elastic modulus. Due to its unusual material properties,BC has recently become a kind of attractive biomedical material in the internationalresearch that was extensively applied to food, paper, biomedical materials, acousticdiaphragms and so on. However, the lower yield of bacterial cellulosecan not meet theindustrial requirement, so how to improve the yield of bacterial cellulose become the focusresearch of many scholars. Therefore, we will do the systemic study on the raise ofproduction of bacterial cellulose by improving the technology and researching itscharacteristics are of great significance.It is quite know that BC is a secondary metabolite so that study on the influence ofnutrient content on cellulose production is very important. In our research, we use twodifferent Gluconacetobacter spp and yeast fermentation to synthetic BC, and the optimumparameters of major factors affecting the yields and productivities of BC were searched inboth two different Kombucha.In the experiment of Gluconacetobacter spp SRTS and yeastfermentation to synthetic BC, five culture factors were examined: temperature, inoculum,the initial pH of medium, volume and inoculum age. The yields and productivities of BCand sugar consumed were measured after cultured statically for22days. Fermentationconditions were optimized by Response surface methodology (RSM) based onBox-Behnken experimental design. Quadratic polynomial mathematical models with goodcorrelation were constructed and employed in the tests. The results show that the optimum conditions of BC fermentation were as follows: inoculum of10.37%, initial pH value of4.96and volume of77.13mL.In the experiment of Gluconacetobacter spp RST and yeast fermentation to syntheticBC, five culture factors were examined: temperature, inoculum, the initial pH of medium,volume and inoculum age. The yields and productivities of BC and sugar consumed weremeasured after cultured statically for22days. Fermentation conditions were optimized byResponse surface methodology (RSM) based on Box-Behnken experimental design.Quadratic polynomial mathematical models with good correlation were constructed andemployed in the tests. The results show that the optimum conditions of BC fermentationwere as follows: temperature of26.54℃, initial pH value of9.99and inoculum age of60.18h. The experimental data and the predicted value of model were fit well.