Liguori Rossana, Soccol Carlos Ricardo, Vandenberghe Luciana Porto de Souza, Woiciechowski Adenise Lorenci, Ionata Elena, Marcolongo Loredana, Faraco Vincenza
Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy.
Department of Bioprocess Engineering and Biotechnology, Federal University of Paraná, Coronel Francisco H. dos Santos Avenue 210, 81531-990 Curitiba, PR, Brazil.
Biomed Res Int. 2015;2015:240231. doi: 10.1155/2015/240231. Epub 2015 Nov 10.
Six Lactobacillus strains were analyzed to select a bacterium for conversion of brewers' spent grain (BSG) into lactic acid. Among the investigated strains, L. acidophilus ATCC 43121 showed the highest yield of lactic acid production (16.1 g/L after 48 hours) when grown in a synthetic medium. It was then analyzed for its ability to grow on the hydrolysates obtained from BSG after acid-alkaline (AAT) or aqueous ammonia soaking (AAS) pretreatment. The lactic acid production by L. acidophilus ATCC 43121 through fermentation of the hydrolysate from AAS treated BSG was 96% higher than that from the AAT treated one, although similar yields of lactic acid per consumed glucose were achieved due to a higher (46%) glucose consumption by L. acidophilus ATCC 43121 in the AAS BSG hydrolysate. It is worth noting that adding yeast extract to the BSG hydrolysates increased both the yield of lactic acid per substrate consumed and the volumetric productivity. The best results were obtained by fermentation of AAS BSG hydrolysate supplemented by yeast extract, in which the strain produced 22.16 g/L of lactic acid (yield of 0.61 g/g), 27% higher than the value (17.49 g/L) obtained in the absence of a nitrogen source.
对六种乳酸杆菌菌株进行了分析，以选择一种能将啤酒糟（BSG）转化为乳酸的细菌。在所研究的菌株中，嗜酸乳杆菌ATCC 43121在合成培养基中生长时，乳酸产量最高（48小时后为16.1克/升）。然后分析了其在经过酸碱（AAT）或氨水浸泡（AAS）预处理的BSG水解产物上的生长能力。嗜酸乳杆菌ATCC 43121通过发酵AAS处理的BSG水解产物产生的乳酸比AAT处理的水解产物高96%，尽管由于嗜酸乳杆菌ATCC 43121在AAS BSG水解产物中的葡萄糖消耗量更高（46%），每消耗葡萄糖产生的乳酸产量相似。值得注意的是，向BSG水解产物中添加酵母提取物提高了每消耗底物的乳酸产量和体积生产率。通过发酵添加酵母提取物的AAS BSG水解产物获得了最佳结果，其中该菌株产生了22.16克/升的乳酸（产量为0.61克/克），比在没有氮源的情况下获得的值（17.49克/升）高27%。
