This study investigates the quantity of bioethanol produced from Zygnema microalgal biomass by performing proximate analysis and determining the reducing sugar concentration prior to fermentation. Bioethanol concentration was measured using a UV-Visible spectrophotometer, and ethanol percentage was estimated following Sirajo et al. (2019). Results indicated that bioethanol yield increased with longer retention times, reaching the highest concentration at Day 9 (0.94±0.15 g/dm³) at pH 7.5 and 30°C, and the lowest at Day 3 (0.54±0.056 g/dm³) at pH 6.5 and 20°C (Table 1). The measured quantity, viscosity, and density of the bioethanol produced were within the recommended ASTM standard ranges, indicating its suitability for use in internal combustion engines without adverse effects.