Production of α-Glycerylphosphorylcholine in Fermented Roots, Tubers, and Fruits

Abstract

Vegetables and fruits, high in starch and sugars, are promising substrates for bioethanol production, but can also yield valuable nootropic compounds, such as alpha-glycerylphosphorylcholine (alpha-GPC). This compound is a known cognitive enhancer that works by increasing the release of acetylcholine, a neurotransmitter essential for learning and memory. In this study, select root and tuber crops, as well as fruits, were subjected to Saccharomyces cerevisiae fermentation to observe the co-production of ethanol and alpha-GPC. The ethanol yields from these substrates were comparable to those from wheat (var. AC Andrew), ranging from 30.44 g/L (beet) to 70.04 g/L (lotus root). Aside from ethanol, alpha-GPC was also produced, with purple top turnip yielding 0.91 g/L, the second highest concentration after wheat (used as a reference), which produced 1.25 g/L. Although alpha-GPC yields in the tested substrates were lower than those from cereal grains (e.g., wheat and barley), a noteworthy observation was the production of methanol in many of these substrates. Methanol was detected in all feedstocks except wheat, with concentrations ranging from 0.10 g/L (cassava) to 1.69 g/L (purple top turnip). A linear regression analysis revealed a strong correlation between methanol and alpha-GPC content (R2 = 0.876; slope = 0.52), suggesting a potential link in their biosynthetic pathways. These feedstocks not only proved effective as substrates for bioethanol production, but also showed potential for generating value-added compounds such as alpha-GPC. This dual-purpose potential presents new market opportunities for producers by leveraging both biofuel and nootropic compound production. Furthermore, the observed relationship between methanol and alpha-GPC production warrants further investigation to elucidate the metabolic pathways involved.