The Present work focused on the development and optimisation of an engineering-oriented biochemical fermentor for producing ethanol from rice straw by incorporating pretreatment chemistry, simultaneous saccharification and fermentation (SSF), material-energy balance, and
mechanical design into one engineering frame. At bench scale, a laboratory-sized 31.17 L batch fermentor was designed and assessed using design-level computations and literature-supported benchmarks. The system produced ethanol at approximately 1 L d⁻¹, with a product rate of
1.0 g L⁻¹ h⁻¹ and 67% fermentable sugar utilisation under thermally favourable conditions (pH 4.8-5.0, temperature range of 37-380C). Energy analysis indicated that distillation was the largest contributor to energy consumption and costs in ethanol production, and that fermentation
efficiency was the primary determinant of ethanol yield. The energy performance of this system matches that of other reported laboratory-scale lignocellulosic ethanol systems. In terms of contributions, this research differs significantly from prior work, which has focused primarily on
biochemical optimisation(i.e., optimising yields)of ethanol production systems rather than on engineering-based design of such systems. The primary limitation of this study was the reliance on design-level energy estimates without including detailed thermal simulations or pilot-scale
validation of the fermentor design. Overall, this study demonstrates the technical feasibility of converting rice straw into ethanol as a sustainable waste valorisation strategy and provides a scalable basis for future process improvement through heat exchange and process optimisation.