The prospect of utilizing yam peel hydrolysate (YPH) as a carbon source for lactic acid (LA) production using Rhizopus orysae was investigated in batch surface and submerged fermentation processes. The kinetics of biomass growth, substrate utilization and LA production were studied using models of modified Luedeking–Piret, logistic and simple Luedeking–Piret equations, respectively, for the surface and submerged processes. The YPH containing 80 g L⁻¹ of reducing sugars (glucose, xylose, ribose and others) was obtained by acid hydrolysis (H₂SO₄) of 100 g L⁻¹ of yam peel and used for fermentation. The LA yield from the YPH was 80.03% and 75.63% for the surface and submerged fermentation, respectively. These values were higher than those of synthetic glucose syrup (SGS), which were 77.36% and 38.96% for surface and submerged fermentation, respectively. The models were satisfactory for the fermentation processes with high accuracy of R² ((0.89 to 0.96), (0.95 to 0.99) and (0.86 to 0.99)) for biomass growth, substrate (SGS/YPH) utilization and LA production, respectively. The models also elucidated that the fermentation process was growth associated (α) instead of non-growth associated (β) because the value of α/β was greater than 1. This justified the other kinetic parameters obtained for the growth phase. Therefore, Rhizopus oryzae effectively converted YPH to LA with a high yield and purity. © 2021 Society of Industrial Chemistry and John Wiley & Sons Ltd

中文翻译：

---

乳酸生产：在动力学研究中使用山药皮水解物作为底物，使用米根霉

研究了利用山药皮水解物（YPH）作为使用米根霉生产乳酸（LA）的碳源在分批表面和深层发酵过程中的前景。分别使用改进的 Luedeking-Piret 模型、逻辑方程和简单的 Luedeking-Piret 方程对表面和水下过程的生物量生长、底物利用和 LA 生产的动力学进行了研究。通过酸水解（H ₂ SO ₄）100 g L ^-1得到含有80 g L ^-1还原糖（葡萄糖、木糖、核糖等）的YPH山药皮，用于发酵。YPH 的表面发酵和深层发酵的 LA 产率分别为 80.03% 和 75.63%。这些值高于合成葡萄糖浆 (SGS)，表面发酵和深层发酵分别为 77.36% 和 38.96%。这些模型对于发酵过程来说是令人满意的，R ²（（0.89 至 0.96）、（0.95 至 0.99）和（0.86 至 0.99））分别用于生物量生长、底物（SGS/YPH）利用和 LA 生产。模型还阐明了发酵过程与生长相关 ( α ) 而不是非生长相关 ( β )，因为α / β的值大于 1。这证明了为生长期获得的其他动力学参数是合理的。因此，米根霉以高产率和高纯度有效地将 YPH 转化为 LA。© 2021 工业化学学会和 John Wiley & Sons Ltd