Zentou Hamid, Zainal Abidin Zurina, Yunus Robiah, Awang Biak Dayang R, Abdullah Issa Mohammed, Yahaya Pudza Musa
Department of Chemical and Environmental Engineering, Universiti Putra Malaysia, Serdang 43400, Malaysia.
ACS Omega. 2021 Feb 1;6(6):4137-4146. doi: 10.1021/acsomega.0c04025. eCollection 2021 Feb 16.
Despite the advantages of continuous fermentation whereby ethanol is selectively removed from the fermenting broth to reduce the end-product inhibition, this process can concentrate minor secondary products to the point where they become toxic to the yeast. This study aims to develop a new mathematical model do describe the inhibitory effect of byproducts on alcoholic fermentation including glycerol, lactic acid, acetic acid, and succinic acid, which were reported as major byproducts during batch alcoholic fermentation. The accumulation of these byproducts during the different stages of batch fermentation has been quantified. The yields of total byproducts, glycerol, acetic acid, and succinic acid per gram of glucose were 0.0442, 0.023, 0.0155, and 0.0054, respectively. It was found that the concentration of these byproducts linearly increases with the increase in glucose concentration in the range of 25-250 g/L. The results have also showed that byproduct concentration has a significant inhibitory effect on specific growth coefficient (μ) whereas no effect was observed on the half-velocity constant ( ). A new mathematical model of alcoholic fermentation was developed considering the byproduct inhibitory effect, which showed a good performance and more accuracy compared to the classical Monod model.
尽管连续发酵具有优势，即能从发酵液中选择性去除乙醇以减少终产物抑制，但该过程会使少量副产物浓缩到对酵母产生毒性的程度。本研究旨在建立一个新的数学模型，以描述包括甘油、乳酸、乙酸和琥珀酸在内的副产物对酒精发酵的抑制作用，这些副产物在分批酒精发酵过程中被报道为主要副产物。已对这些副产物在分批发酵不同阶段的积累进行了量化。每克葡萄糖产生的总副产物、甘油、乙酸和琥珀酸的产量分别为0.0442、0.023、0.0155和0.0054。研究发现，在25 - 250 g/L范围内，这些副产物的浓度随葡萄糖浓度的增加呈线性增加。结果还表明，副产物浓度对比生长系数（μ）有显著抑制作用，而对半速度常数（ ）没有影响。考虑到副产物抑制作用，建立了一个新的酒精发酵数学模型，与经典的莫诺德模型相比，该模型表现良好且更准确。
