Investigation of bioethanol production from tea wastes by using different microorganisms

In this study, bioethanol production using tea wastes as a substrate source has been investigated by different microorganisms. The reducing sugars in holocelulose structure were obtained by applying acidic, basic and enzymatic pre-treatment techniques to the tea wastes. In dilute acid hydrolysis experiments, the parameters of temperature, time, solid concentration, acid concentration, and particle size have been optimized. According to the results obtained from the hydrolysis experiments by dilute sulphuric acid, the optimum conditions were determined as the pre-treatment time of 130 min., tea concentration of 55 g / L, acid concentration of 1,15 % (v / v), the geometric mean particle size of 840 µ, and at the temperature of 120 °C. In the hydrolysis carried out at the optimum conditions, % 35 of the sugar with holocelulose (cellulose+hemicellulose) structure was passed to the hydrolysate media. The fermentation experiments were performed as batch and by supplying anaerobic conditions. The working volume was 100 mL in the 250 mL volumetric flasks. As a result of the fermentation experiments, production yields values for E. coli KO11 and S. cerevisiae were obtained as 5,1 g/L and 3 g/L, respectively. Furthermore, in this thesis, the hydrolysis and bioethanol production yields of another tea samples such as factory waste, green tea and packets were also investigated and compared with the tea waste used.