González-Orozco Brianda D, Kosmerl Erica, Jiménez-Flores Rafael, Alvarez Valente B
Department of Food Science and Technology, The Ohio State University, Columbus, OH, United States.
Front Microbiol. 2023 Aug 3;14:1236634. doi: 10.3389/fmicb.2023.1236634. eCollection 2023.
Due to the increasing consumer demand for the development and improvement of functional foods containing probiotics, new probiotic candidates need to be explored as well as novel means to enhance their beneficial effects. OSU-BDGOA1 is a strain isolated from kefir grains that has demonstrated probiotic traits. This species is the main inhabitant of kefir grains and is responsible for the production of an exopolysaccharide (EPS) whit vast technological applications and potential bioactivities. Research has shown that interkingdom interactions of yeast and lactic acid bacteria can enhance metabolic activities and promote resistance to environmental stressors.
Comparative genomic analyses were performed to distinguish OSU-BDGOA1 from other strains of the same species, and the genome was mined to provide molecular evidence for relevant probiotic properties. We further assessed the cumulative effect on the probiotic properties of OSU-BDGOA1 and yeast co-culture compared to monocultures.
Survival during simulated digestion assessed by the INFOGEST digestion model showed higher survival of OSU-BDGOA1 and in co-culture. The adhesion to intestinal cells assessed with the Caco-2 intestinal cell model revealed enhanced adhesion of OSU-BDGOA1 in co-culture. The observed increase in survival during digestion could be associated with the increased production of EPS during the late exponential and early stationary phases of co-culture that, by enhancing co-aggregation between the yeast and the bacterium, protects the microorganisms from severe gastrointestinal conditions as observed by SEM images. Immune modulation and barrier function for recovery and prevention of flagellin-mediated inflammation by Typhimurium heat-killed cells (HKSC) in Caco-2 cells were also measured. OSU-BDGOA1 in mono- and co-culture regulated inflammation through downregulation of pro-inflammatory cytokine expression and increased membrane barrier integrity assessed by TEER, FD4 permeability, and expression of tight junctions.
The results of the study warrant further research into the application of co-cultures of yeast and LAB in functional probiotic products and the potential to increase EPS production by co-culture strategies.
由于消费者对含益生菌的功能性食品的开发和改进需求不断增加，需要探索新的益生菌候选菌株以及增强其有益效果的新方法。OSU-BDGOA1是从开菲尔粒中分离出的一种已表现出益生菌特性的菌株。该物种是开菲尔粒的主要栖息菌，负责产生具有广泛技术应用和潜在生物活性的胞外多糖（EPS）。研究表明，酵母和乳酸菌的跨界相互作用可增强代谢活性并促进对环境应激源的抗性。
进行比较基因组分析以区分OSU-BDGOA1与同一物种的其他菌株，并挖掘基因组以提供相关益生菌特性的分子证据。我们进一步评估了与单培养相比，OSU-BDGOA1与酵母共培养对益生菌特性的累积影响。
通过INFOGEST消化模型评估的模拟消化过程中的存活率显示，OSU-BDGOA1在共培养中的存活率更高。用Caco-2肠细胞模型评估的对肠细胞的粘附显示，OSU-BDGOA1在共培养中的粘附增强。观察到的消化过程中存活率的增加可能与共培养的指数后期和稳定期早期EPS产量的增加有关，通过增强酵母和细菌之间的共聚集，保护微生物免受严重的胃肠道条件影响，如扫描电子显微镜图像所示。还测量了Caco-2细胞中OSU-BDGOA1对鼠伤寒沙门氏菌热灭活细胞（HKSC）介导的鞭毛蛋白介导的炎症的免疫调节和屏障功能恢复及预防作用。单培养和共培养中的OSU-BDGOA1通过下调促炎细胞因子表达来调节炎症，并通过TEER、FD4通透性和紧密连接表达评估增加膜屏障完整性。
该研究结果值得进一步研究酵母和乳酸菌共培养在功能性益生菌产品中的应用以及通过共培养策略增加EPS产量的潜力。
