Divyashree S, Anjali P G, Somashekaraiah Rakesh, Sreenivasa M Y
Department of Studies in Microbiology, University of Mysore, Mysuru, Karnataka, India.
Biotechnol Rep (Amst). 2021 Sep 6;32:e00672. doi: 10.1016/j.btre.2021.e00672. eCollection 2021 Dec.
A total of 130 isolates were screened, twelve isolates were characterized for probiotic attributes and two isolates with best probiotic features were evaluated in the study. Isolates MYSRD108 and MYSRD71 survived gastric conditions and were susceptible to tested antibiotics. Isolates showed more vital cell surface traits such as autoaggregation of 89.2 and 88.5% and cell surface hydrophobicity of 61 and 64%. PCR amplification followed by 16sRNA sequencing results confirmed that the isolates as (MYSRD 108) and (MYSRD 71). During this study, the Cells and their Cell Free Supernatant (CFS) were examined for antimicrobial activity. Both the isolates inhibited different bacterial pathogens in which the growth of was significantly reduced. Further, their CFS also showed inhibitory effects against with agar well diffusion and Minimum Inhibitory Concentration using Broth micro dilution method. The antimicrobial compounds in the CFS was characterized to different constraints such as pH neutralization, heat treatment, Hydrogen peroxide test and storage stability at -20> °C and represented that the antagonistic acitivity against is due to the presence of organic acids in the supernatants that lowered the pH. These strains were further examined for the inhibition of biofilm. The results indicated that CFS reduced biofilm by more than 75% and the number of biofilm was effectively reduced using 15% concentration of CFS. These strains may be used to produce antimicrobial compounds which can be a substitute for chemical preservatives in food industry.
共筛选了130株分离株,对12株分离株进行了益生菌特性鉴定,并在研究中对具有最佳益生菌特性的2株分离株进行了评估。分离株MYSRD108和MYSRD71在胃部环境中存活,且对测试抗生素敏感。分离株表现出更重要的细胞表面特征,如自聚集率分别为89.2%和88.5%,细胞表面疏水性分别为61%和64%。PCR扩增后进行16sRNA测序结果证实,这些分离株为(MYSRD 108)和(MYSRD 71)。在本研究中,对细胞及其无细胞上清液(CFS)进行了抗菌活性检测。两种分离株均抑制不同的细菌病原体,其中[具体细菌名称]的生长显著降低。此外,它们的CFS通过琼脂孔扩散法和肉汤微量稀释法测定最低抑菌浓度,也显示出对[具体细菌名称]的抑制作用。CFS中的抗菌化合物通过不同的条件进行了表征,如pH中和、热处理、过氧化氢测试以及在-20°C下的储存稳定性,结果表明对[具体细菌名称]的拮抗活性是由于上清液中存在有机酸降低了pH值。进一步检测了这些菌株对[具体细菌名称]生物膜的抑制作用。结果表明,CFS使[具体细菌名称]生物膜减少了75%以上,使用15%浓度的CFS可有效减少[具体细菌名称]生物膜的数量。这些菌株可用于生产抗菌化合物,在食品工业中可作为化学防腐剂的替代品。