Biorefinery Potential of Parkia biglobosa Seed Coat Through Phenolic Recovery Followed by Bioethanol Production

Abstract The Parkia biglobosa seed coat is a residue from African locust bean processing that warrants investigation as a feedstock for sequential product recovery. This review proposes a cascade in which phenolic compounds are recovered before the remaining solids are converted to bioethanol. A targeted narrative assessment connects seed-coat composition and phytochemical screening with extraction and conversion studies on other biomass and with established analytical methods. Reported tannins motivate investigation of a phenolic-containing extract, but the available evidence does not establish its recovery yield or the fermentability of the resulting seed-coat residue. The proposed sequence comprises feedstock preparation, aqueous or aqueous-ethanol extraction, extract and solvent recovery, composition-informed pretreatment, enzymatic hydrolysis, fermentation, and ethanol separation. Its central requirement is compatibility between stages: extraction must recover a useful phenolic fraction while preserving sufficient convertible carbohydrate. Particular attention is given to soluble-sugar losses, interpretation of phenolic assays, pretreatment-derived inhibitors, and differentiation of the extraction solvent from newly produced ethanol. Proximate carbohydrate content is not treated as measured glucose or glucan, and no feedstock-specific ethanol yield is predicted. The contribution is a testable integration framework that links both products to the same initial biomass and makes unresolved material flows explicit. Establishing residual-solid composition, extract quality, and actual sugar-to-ethanol conversion would determine whether the proposed cascade merits further development. Economic and environmental benefits remain hypotheses requiring dedicated assessment. Keywords: Parkia biglobosa; seed coat; cascade biorefinery; phenolic recovery; enzymatic hydrolysis; bioethanol.