Abstract:

The feasibilities of fermentation wastewater treatment and high-quality protein production by Chlorella pyrenoidosa was investigated. The removal rate of TP, TN, NH₃-N, COD and BOD separately reached 99.5%, 95.1%, 99.4%, 98.2% and 99.7% by C. pyrenoidosa under fed-batch treatment mode, which was 1.47, 1.45, 1.22, 1.13, and 1.19-fold more than batch treatment mode, respectively. The effluent quality of fermentation wastewater treated with C. pyrenoidosa met discharge standard of GB 25463—2010. The biomass and protein yield of C. pyrenoidosa subjected to fermentation wastewater treatment were separately 48.53g/L and 27.20g/L. The proportions of 18 amino acids and essential amino acids in C. pyrenoidosa protein were separately 58.56% and 26.44%. The amino acid score was 65.3, which indicated that C. pyrenoidosa protein was a high-quality single-cell protein source. Additionally, C₁₆—C₁₈ occupied approximate 86% of total fatty acids and also the contents of linoleic acid and linolenic were separately 27.06% and 25.82% in C. pyrenoidosa. Synchronously, the safety indexes of heavy metals and microorganisms of C. pyrenoidosa complied with GB 13078—2017 health standards for fodder. The digestibility of dry matter, crude protein, crude fat, and starch of C. pyrenoidosa in simulative pig intestinal gastric juice in vitro were separately 79.02%, 90.17%, 92.93%, and 87.81%. The bioavailability of small intestinal Caco-2 cells to peptides, triglycerides, free fatty acid, and carbohydrates of digestive C. pyrenoidosa were separately 97.57%, 85.79%, 91.55% and 35.22%, which were roughly equivalent to the digestibility and bioavailability of other feed protein such as corn and soybean. The outcomes of this work could provide a basis for industrial wastewater treatment coupling co-production of high-value fine chemicals by other microalgae.

Key words: biomass, fermentation wastewater, protein fodder, amino acid, digestion

摘要：

考察利用小球藻强化处理曲霉发酵废水（发酵废水）并联产高质蛋白饲料的可行性。小球藻在流加补料模式下使得发酵废水总磷（TP）、总氮（TN）、氨氮（NH₃-N）、化学需氧量（COD）、生化需氧量（BOD）去除率分别达到99.5%、95.1%、99.4%、98.2%和99.7%，较分批模式下污染物去除率提高了1.47倍、1.45倍、1.22倍、1.13倍和1.19倍，且其出水水质符合GB 25463—2010排放标准。联产获得小球藻生物量和蛋白高达48.53g/L和27.20g/L，藻蛋白中18种氨基酸含量为58.56%，8种必需氨基酸含量为26.44%，氨基酸评分65.3，属优质单细胞蛋白源。小球藻脂肪酸以C₁₆~C₁₈为主（˃86%），亚油酸和亚麻酸含量分别为27.06%和25.82%。小球藻重金属（铅、砷、镉、汞、铬）和微生物（沙门氏菌、霉菌、细菌）安全指标符合GB 13078—2017饲料卫生标准。进一步地，体外模拟猪肠胃液对藻粉干物质、粗蛋白、粗脂肪和淀粉消化率为79.02%、90.17%、92.93%和87.81%，小肠Caco-2细胞对藻粉消化物多肽、甘油三酯、游离脂肪酸和碳水化合物吸收率为97.57%、85.79%、91.55%和35.22%，与常规玉米、豆粕饲料消化吸收率相当，结果可为他种微藻净化工业废水耦合高值精细化学品生产提供依据。

关键词: 生物质, 发酵废水, 蛋白饲料, 氨基酸, 消化吸收