Alfano Alberto, Parecha Darshankumar, Fusco Alessandra, Savio Vittoria, De Chiara Ida, Muscariello Lidia, Donnarumma Giovanna, Schiraldi Chiara
Department of Experimental Medicine, University of Campania Luigi Vanvitelli, Napoli, Italy.
Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania Luigi Vanvitelli, Caserta, Italy.
BMC Biotechnol. 2025 Jul 1;25(1):62. doi: 10.1186/s12896-025-00997-z.
There is growing interest in newly isolated lactic acid bacteria from traditional sources. In this study, a Lactococcus lactis strain identified and isolated from natural whey starter cultures of cow milk for the production of artisanal cheeses was cultivated in optimized vegan grade medium to assess its growing ability and metabolic fingerprint. In fact, traditionally fermented dairy products are considered nutritionally complete and possibly functional to human health with a number of benefits not only to the gastro-intestinal tract but also in a systemic manner.
In fed batch experiments, we achieved 14 g/L dry cell weight and 1.9∙10 viable colony forming unit increasing the values of experiment threefold and twofold respect to the batch processes, respectively. Additionally, the lactic acid (LA) production was quantified, and a maximal concentration of 78 g/L was achieved, which is approximately five-fold corresponding to the batch experiment results. This is in agreement with kinetic modeling of LA inhibition studies that highlighted a halved growth rate (µ) at 35 ± 5 g/L of LA whilst the growth blockage occurred at about 80 g/L. The samples obtaining after ultrafiltration processes and tested on three different pathogens, Enterococcus faecalis, Salmonella enterica subsp. enterica serovar Typhimurium and enteroinvasive Escherichia coli, gave a reduction on viability by 6-9 log on average.
This paper focused its attention on optimization of fermentation conditions (in particular a vegan grade media using Design of Experiment approach) using fed-batch and microfiltration processes increasing the production of biomass and bioactive molecules, with respect to the batch processes. At the end of the fed-batch fermentation, a downstream process based on membranes was performed in order to obtain bioactive molecules that proved antimicrobial activity against intestinal/food spoilage pathogens.
人们对从传统来源新分离出的乳酸菌越来越感兴趣。在本研究中，从用于生产手工奶酪的牛奶天然乳清发酵剂培养物中鉴定并分离出的一株乳酸乳球菌，在优化的纯素等级培养基中培养，以评估其生长能力和代谢指纹。事实上，传统发酵乳制品被认为营养全面，可能对人体健康有益，不仅对胃肠道有诸多益处，而且对全身也有好处。
在补料分批实验中，我们分别实现了14 g/L的干细胞重量和1.9×10个活菌落形成单位，与分批培养过程相比，实验值分别提高了三倍和两倍。此外，对乳酸（LA）产量进行了定量，达到了78 g/L的最大浓度，约为分批实验结果的五倍。这与LA抑制研究的动力学模型一致，该模型强调在35±5 g/L的LA浓度下生长速率（µ）减半，而在约80 g/L时生长受阻。超滤过程后获得的样品在三种不同病原体（粪肠球菌、肠炎沙门氏菌亚种肠炎血清型鼠伤寒沙门氏菌和肠侵袭性大肠杆菌）上进行测试，平均使活力降低了6-9个对数。
本文重点关注使用补料分批和微滤工艺优化发酵条件（特别是采用实验设计方法的纯素等级培养基），相对于分批工艺增加生物质和生物活性分子的产量。在补料分批发酵结束时，进行了基于膜的下游工艺，以获得对肠道/食品腐败病原体具有抗菌活性的生物活性分子。
