厌氧发酵产酸是酱渣资源化的新途径。研究表明,基质与微生物之比(F/M)越低,酱渣预处理液厌氧发酵产酸的效果越好。当F/M为1∶1时,预处理液中可溶性蛋白质及碳水化合物的降解率最高,分别为71.23%和73.43%;酸性、中性和碱性蛋白酶及α-淀粉酶的活性最大,分别为5.336 U/mL、3.964 U/mL、4.726 U/mL及14.04μg maltose/min;单位体积酱渣预处理液发酵所得挥发性脂肪酸(VFA)的浓度和乙酸浓度均最高,分别为0.17g/mL和0.14g/mL,乙酸占总末端发酵产物比例也最大,为82.19%。可溶性蛋白质在发酵初期(2 d内)的转化主要源于酸性蛋白酶的催化降解。发酵产物包括乙醇、乙酸、丙酸、异丁酸、正丁酸、戊酸等,但均以乙酸为主。不同F/M条件下,厌氧产酸过程中均存在明显的丙酸累积现象,F/M为20∶1时,丙酸累积量最高,约为4.00 g/L。

Anaerobic acidogenesis provides a novel pathways to reutilize soy sauce residue.The results showed that the efficiency of anaerobic acidogenesis was improved along with decreasing F /M.When F /M was 1 ∶ 1,more VFA,especially acetate,was produced from soy sauce residue.The degradation rates of soluble proteins and carbohydrates were highest with 71.23% and 73.43%.The activities of acid-protease,neutral-protease,alkaline-protease and α-amalyse were also highest with 4.116 U /mL,3.812 U /mL,3.049 U /mL and 13.72 ug maltose /min,respectively.The yields of the total organic acids and acetatic acid per unit substrate were 0.17 g /mL and 0.14 g /mL.And,the percentage of acetatic acid in the total VFA amounted to 82.19%.The conversion of soluble proteins at the beginning period of fermentation was due to the catalytic degradation of acid-protease.The fermentation products involved in ethanol,acetatic aicd,propionatic acid,iso-butyratic acid,butyratic acid and valeratic acid.A certain amount of propionatic acid accumulated during the anaerobic acidogenesis.Under 20∶ 1 F /M,the concentration of propionatic acid was highest with around 4.00 g /L.