The present work tested the bioethanol production by two strains of yeast, Saccharomyces cerevisiae. The marine strain displayed higher bioethanol production than the terrestrial strain did and hence, it was selected for optimizing the fermentation conditions for ethanol production by using the center composite design of response surface methodology. The R2 value of 0.92 of statistical model revealed its acceptability. The factors such as temperature, incubation period, acid processed sawdust and agitation were optimized on bioethanol production by S. cerevisiae. The marine strain showed the maximum ethanol production of 69.58% of total distillate under the optimal conditions: temperature 30 °C, sawdust concentration of 6.84 mg/l under the agitation speed of 360 rpm at 89 h of incubation. This work revealed that mangrove-derived marine yeast strain of S. cerevisiae was potential for bioethanol production over the terrestrial strain.