Department of Chemical Engineering and Food Technology, Faculty of Sciences, IVAGRO, University of Cádiz, Puerto Real, Spain.
J Sci Food Agric. 2021 Aug 15;101(10):4108-4117. doi: 10.1002/jsfa.11046. Epub 2021 Jan 28.
Exhausted sugar beet pulp pellets (ESBPP) were used as raw material for lactic acid (LA) fermentation. The enzymatic hydrolysis of ESBPP was performed with the solid obtained after the fungal solid-state fermentation of ESBPP as a source of hydrolytic enzymes. Subsequently, a medium rich in glucose and arabinose was obtained, which was used to produce LA by fermentation. For LA production, two Lactobacillus strains were assayed and the effects of the supplementation of the hydrolysate with a nitrogen source and the mode of pH regulation of the fermentation were investigated. Moreover, a kinetic model for LA fermentation by Lactobacillus plantarum of ESBPP hydrolysates was developed.
L. plantarum produced a LA concentration 34% higher than that produced by L. casei. The highest LA concentration (30 g L ) was obtained with L. plantarum when the hydrolysate was supplemented with 5 g L yeast extract and the pH was controlled with CaCO . The concentration of acetic acid differed depending on the concentration of CaCO added, producing its maximum value with 27 g L CaCO . The proposed kinetic model was able to predict the evolution of substrates and products depending on the variation of the pH in the hydrolysate, according to the amount of CaCO added.
ESBPP can be revalorised to produce LA. A pure LA stream or a mixture of LA and acetic acid, depending on the pH control method of the fermentation, can be produced. Thus, this control is of great interest depending on the destination of the effluent. © 2020 Society of Chemical Industry.
利用废弃的糖用甜菜渣颗粒（ESBPP）作为原料进行乳酸（LA）发酵。采用 ESBPP 真菌固态发酵后的固体作为水解酶源对 ESBPP 进行酶解。随后，得到富含葡萄糖和阿拉伯糖的培养基，用于发酵生产 LA。对于 LA 生产，我们检测了两种乳杆菌菌株，并研究了水解物补充氮源和发酵过程中 pH 调节方式的影响。此外，还建立了 ESBPP 水解物发酵生产 LA 的动力学模型。
与 L. casei 相比，L. plantarum 产生的 LA 浓度高 34%。当水解物补充 5 g/L 酵母提取物并用 CaCO 控制 pH 时，L. plantarum 可获得最高的 LA 浓度（30 g/L）。添加 CaCO 的浓度不同，产生的乙酸浓度也不同，当添加 27 g/L CaCO 时，乙酸浓度达到最大值。所提出的动力学模型能够根据水解物 pH 的变化来预测基质和产物的演变，具体取决于 CaCO 的添加量。
ESBPP 可以回收利用来生产 LA。可以根据发酵的 pH 控制方法生产出纯净的 LA 流或 LA 和乙酸的混合物，这取决于废水的去向。因此，这一控制方法非常有趣。© 2020 英国化学学会。
