Biorefi ning of food waste has gained increasing attention as a sustainable approach for producing platform chemicals 

such as lactic acid. In this study, corncob (CC), a byproduct of corn processing, was utilized as a feedstock for biorefi ning 

through biomass hydrolysis and lactic acid fermentation. Due to the low enzymatic digestibility of raw CC caused by its 

lignin content, KOH pretreatment was conducted prior to enzymatic hydrolysis to enhance glucose recovery. Among the 

tested KOH concentrations (1–5%), 3% KOH pretreatment yielded the highest biomass-to-glucose conversion (25.38%), 

with a solid recovery (SR) of 47.60%, glucan content (GC) of 57.23%, and enzymatic digestibility (ED) of 84.70%. These 

values represent a signifi cant improvement compared to raw CC (biomass-to-glucose conversion: 7.97%; SR: 100%; GC: 

35.22%; ED: 20.57%). Compositional and physicochemical analyses confi rmed that 3% KOH-pretreated CC (3%KpCC) had 

a reduced lignin content (11.69%) compared to raw CC (20.48%), along with irregular cracks and crevices that improved 

enzymatic digestibility via easier enzyme access. Fermentation of Lacticaseibacillus rhamnosus with the hydrolysate as 

an alternative carbon source for 24 h was found to produce about 9.89 g/L lactic acid and 98.9% conversion, similar to the 

control medium (about 9.81 g/L production and 98.1% conversion). Overall, the mass balance analysis revealed a 3.2-fold 

increase in lactic acid production (251 g/kg biomass) with the 3% KOH pretreatment process compared to the control. This 

study demonstrates a signifi cantly improved biorefi nery strategy that eff ectively contributes to both CC waste management 

and value-added chemical production.