Laboratory of Marines Biotechnologies and Environment (BIOMARE), Faculty of Sciences BO. Box 20, Chouaib Doukkali University, El Jadida 24000, Morocco.
Laboratory of Genetic, Biodiversity and Bio-Resources Valorisation, University of Monastir, Monastir, Tunisia.
World J Microbiol Biotechnol. 2023 Oct 6;39(12):331. doi: 10.1007/s11274-023-03784-0.
The present study aimed at characterizing lactic acid bacteria (LAB) strains isolated from traditional sourdoughs collected in different regions of Morocco. Isolated strains were firstly identified using Gram staining and catalase reaction test. Presumptive LAB strains were then checked for various phenotypical properties including growth at 45 °C, resistance to NaCl, enzyme production, acidification capacity, diacetyl and exopolysaccharide (EPS) production, and antifungal activity. Finally, selected LAB strains were identified using 16S rDNA sequencing. Results showed that 32.1% of the isolates were thermophilic (45 °C) and 83.9% were resistant to NaCl (6.5%). Moreover, 51.7 and 37.5% were able to produce diacetyl and EPS, respectively. Regarding enzyme production, 55.3 and 7.1% of the isolates showed lipolytic and proteolytic activities, respectively. Low pH values (3.37-3.76) were obtained after 24 h of incubation of LAB strains in de Man, Rogosa and Sharpe (MRS) broth. Antifungal activity test against Aspergillus flavus, Aspergillus niger and Penicillium spp. showed an inhibition rate up to 50%. Bacterial DNA sequencing showed that LAB isolates belong to seven species, chiefly Levilactobacillus brevis, Lentilactobacillus parabuchneri, Lactiplantibacillus plantarum, Pediococcus pentosaceus, Enterococcus hirae, Bifidobacterium pseudocatenulatum, and Companilactobacillus paralimentarius. These findings, for the first time in Moroccan sourdoughs, indicate that the isolated LAB strains have good multifunctional properties and could be suitable as good starters for sourdough bread production under controlled conditions.
本研究旨在对从摩洛哥不同地区采集的传统酸面团中分离的乳酸菌（LAB）菌株进行特征描述。首先通过革兰氏染色和过氧化氢酶反应试验对分离株进行鉴定。然后，对假定的 LAB 菌株进行各种表型特性检查，包括在 45°C 下的生长情况、耐盐性、酶的产生、酸化能力、双乙酰和胞外多糖（EPS）的产生以及抗真菌活性。最后，使用 16S rDNA 测序鉴定选定的 LAB 菌株。结果表明，32.1%的分离株为嗜热菌（45°C），83.9%的分离株耐盐（6.5%）。此外，51.7%和 37.5%的分离株分别能够产生双乙酰和 EPS。关于酶的产生，55.3%和 7.1%的分离株分别具有脂肪酶和蛋白酶活性。LAB 菌株在德芒、罗高萨和夏普（MRS）肉汤中培养 24 小时后，可获得低 pH 值（3.37-3.76）。对黄曲霉、黑曲霉和青霉属的抗真菌活性测试表明，抑制率高达 50%。细菌 DNA 测序结果表明，LAB 分离株属于七种物种，主要是短乳杆菌、副双歧杆菌、植物乳杆菌、戊糖片球菌、海氏肠球菌、假双歧杆菌和拟双歧杆菌。这些发现，这是在摩洛哥酸面团中首次发现，表明分离的 LAB 菌株具有良好的多功能特性，可作为在控制条件下生产酸面团面包的良好发酵剂。
