Mikrobiyal Selüloz Üretimi ve Üretim Koşullarının Araştırılması

Abstract

The aim of this study is to identify cellulose producing microorganisms isolated from homemade vinegars and to investigate the production of low cost microbial cellulose using these microorganisms and herbal teas, factors affecting microbial cellulose production and properties of cellulose. For this reason, bacteria with the highest cellulose production and yeast were selected from the isolates and mixed cultures were prepared by combining them in certain proportions. The microbial cellulose productions of these cultures were compared. It was determined that the most effective culture for microbial cellulose production was the mixed culture prepared by combining Komagataeibacter europaeus and Zygosaccharomyces parabailii in a 2:1 ratio. Microbial cellulose productions were compared using this culture and three different herbal teas (black tea, green tea and hibiscus tea) as production medium. Accordingly; It was determined that the most effective herbal tea as an alternative production medium for microbial cellulose production was 10% green tea. By comparing the microbial cellulose productions of different carbon sources (glucose, sucrose, lactose, maltose and fructose), it was determined that the highest microbial cellulose production occurred with 10% glucose in green tea medium. When additional nitrogen sources were added to the basic medium prepared with green tea and glucose to increase production, there was no significant increase in microbial cellulose production. In order to determine the appropriate physiological conditions affecting the microbial cellulose production and to increase the production, microbial cellulose production was carried out at different pH, inoculum ratio, temperature, agitation rates and different incubation times. In the medium prepared with 10% green tea and 10% glucose, it was determined that the optimum physiological conditions for microbial cellulose production were achieved at; medium with pH 5, inoculation ratio of 20% and incubation under static conditions with an incubation period of 168 hours at 30°C. As a result of the study, it was determined that the amount of microbial cellulose obtained in Hestrin & Schramm medium increased from 14.7 g/L to 43.75 g/L in green tea medium. In order to determine the effect of light on the production, production was carried out in dark and lighted conditions and it was determined that light had no effect on microbial cellulose production. Also in addition to these, ascorbic acid and vegetable oils were added to the medium in order to increase the production. It was determined that the cellulose production amount increased by 2.4% with 1% ascorbic acid added to the medium with 1% v / v ratio and reached 44.8 g/L, while, it was determined that with 2% olive oil added to the medium, the production increased by 3.5% to 45.35 g/L. It was also found that olive oil, sunflower oil and coconut oil increased microbial cellulose production up to 2.5% concentration. The high amount of microbial cellulose was produced with the reuse of green tea, which was used in the study and became waste, in the same medium again, and it was shown that the low-cost green tea can be used in microbial cellulose production 10 times in a row. Cellulose produced in our study was characterized by SEM (Scanning Electron Microscope) image, FTIR (Fourier Transform Infrared Spectroscopy) and TGA (Thermogravimetric Analysis) analyzes. As a result, it was shown that microbial cellulose production can be achieved with low-cost green tea medium using the mixed culture prepared with microorganisms isolated from homemade vinegar.