Determination of agricultural waste and microalgae biomass usagecapacities for biobutanol production

In this thesis, it was aimed to investigate the use of industrial tea wastes (ITW) as second generation raw material and Dunaliella salina biomass as third generation raw material for renewable and sustainable biobutanol production. In this context, initially, the medium was optimized by examining initial ITW sugar concentration, nitrogen source type and concentration, and concentrations of Mg2+, Fe2+ and Zn2+ mineral salts. Additionally, the effect of fermentation time on biobutanol production was investigated.As a result of optimization studies, the highest total ABE, biobutanol concentration, biobutanol yield (g/g) and biobutanol productivity (g/L/h) obtained as 9.73 g/L, 6.21 g/L, 0.258 g/g and 0.065 g/L/h using 40 g/L ITW sugar, 0.1 g/L MgSO4.7H2O, 0.01 g/L FeSO4.7H2O and 0.001 g/L ZnSO4.7H2O after 96 hours, respectively. Additionally, in studies with D. salina biomass, parameters such as microalgae cultivation conditions, initial mixotrophic microalgal biomass concentration and fermentation time were optimized for biobutanol production. As a result of the study, the highest total ABE, biobutanol, biobutanol yield (g/g) and biobutanol productivity (g/L/h) in P2 medium containing 200 g/L microalgae biomass and 60 g/L glucose were determined as 13.89 g/L, 11.88 g/L, 0.331 g/g and 0.165 g/L/h after 72 hours, respectively. The results obtained from the study show that both ITW and D. salina biomass are promising raw materials for biobutanol production by Clostridium beijerinckii DSMZ 6422. Furthermore, ITW was evaluated in the literature on biobutanol production for the first time. The thesis is the first study in which D. salina was grown mixotrophically using marble waste.