Cheng Wenjun, Chen Xuehan, Gong Lipeng, Wei Jinyu, Ding Jian, Shi Zhongping
The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China.
ACS Omega. 2022 Jan 11;7(3):2918-2928. doi: 10.1021/acsomega.1c05840. eCollection 2022 Jan 25.
Recombinant semisolid hazardous waste treatment is difficult and traditional solid waste treatment is not applicable. However, wastes have features of high density and enriched proteins/polysaccharides, which could supply nitrogen/carbon sources for butyric acid production. The waste was first treated using NaOH to form a waste yeast suspension, and then the suspension was mixed with glucose to obtain a starting medium containing 5.6 g DCW/L (dry cell weight) yeast to initiate butyrate fermentation. The suspension was intermediately supplemented to bring the total waste yeast concentration to 26.3 g DCW/L while continuously feeding the concentrated glucose solution. With the proposed strategy, butyrate concentration reached high levels of 51.0-54.0 g/L using as the strain. Amino acids/oligosaccharides/SO in the suspension, raw material costs, complicated pretreatment process, and butyric acid cleaner production could be effectively utilized, reduced, eliminated, and realized. However, the apparent waste reduction rate was only 49% per batch, thus a "tanks in-series type's repeated waste treating system" model was developed to theoretically explore the possibility of increasing the waste yeast reduction rate . The simulation results indicated that when setting the treatment unit numbers at 4, waste solid concentration could decrease from 26.3 to 3.37 g DCW/L and the hazardous waste yeast reduction rate would increase from 49 to 97%.
重组半固体危险废物处理困难，传统固体废物处理方法不适用。然而，这些废物具有高密度以及富含蛋白质/多糖的特点，可为丁酸生产提供氮/碳源。首先用氢氧化钠处理该废物以形成废酵母悬浮液，然后将该悬浮液与葡萄糖混合，得到含有5.6 g DCW/L（干细胞重量）酵母的起始培养基，以启动丁酸盐发酵。在连续进料浓缩葡萄糖溶液的同时，对悬浮液进行中间补充，使废酵母总浓度达到26.3 g DCW/L。采用所提出的策略，使用该菌株时丁酸盐浓度达到了51.0 - 54.0 g/L的高水平。悬浮液中的氨基酸/寡糖/SO、原材料成本、复杂的预处理过程以及丁酸清洁生产都能够得到有效利用、降低、消除并实现。然而，每批废物的表观减少率仅为49%，因此开发了一种“串联罐式”重复废物处理系统模型，以从理论上探索提高废酵母减少率的可能性。模拟结果表明，当将处理单元数量设置为4时，废固体浓度可从26.3 g DCW/L降至3.37 g DCW/L，危险废酵母减少率将从49%提高到97%。
