Food Biotechnology Research Group, Institute of Food and Beverage Innovation, Zurich University of Applied Sciences (ZHAW), Einsiedlerstrasse 31, 8820 Wädenswil, Switzerland; Department of Biological Sciences, First Technical University, Ibadan, Nigeria.
Food Biotechnology Research Group, Institute of Food and Beverage Innovation, Zurich University of Applied Sciences (ZHAW), Einsiedlerstrasse 31, 8820 Wädenswil, Switzerland.
Int J Food Microbiol. 2022 Apr 2;366:109563. doi: 10.1016/j.ijfoodmicro.2022.109563. Epub 2022 Feb 5.
MALDI-TOF MS is a technique for high-throughput characterization of foodborne microbiota, however, its application for studying African traditional fermented foods is limited. A total of 164 out of 220 lactic acid bacterial (LAB) isolates from Kunu-zaki were identified using MALDI-TOF MS, with 100% identity of representative strains compared to 16S rRNA gene sequencing. MALDI-TOF MS profiling combined with 16S rRNA gene sequencing revealed a total of 15 LAB species in Kunu-zaki, where the most predominant species were Lactiplantibacillus plantarum (40.46%), Weissella confusa (27.27%), and Pediococcus pentosaceus (15.00%). Phenotypic screening of all isolates revealed strains of W. confusa (57), Lactiplantibacillus sp. (9), Companilactobacillus musae (1), Ligilactobacillus saerimneri (1) and Leuconostoc citreum (1) that are capable of producing dextran and/or fructan. Dextransucrase genes were detected in all EPS-producing strains by PCR. Weissella confusa YKDIA1 and YKDIA4 produced 11.93 and 11.70 g/L dextran from millet-sorghum flour hydrolysate-sucrose, respectively. Kunu-zaki produced using W. confusa YKDIA1 had high water holding capacity (100%) and viscosity ranging from 49.46-139.24 mPas. In this study, MALDI-TOF MS adequately revealed the LAB species composition in Kunu-zaki in a high-throughput strategy and further, the dominant occurrence of EPS-producing LAB strains and their potentials to influence the rheological properties of Kunu-zaki were demonstrated.
基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）是一种高通量鉴定食源性微生物的技术，但在研究非洲传统发酵食品方面的应用有限。采用 MALDI-TOF MS 对 220 株库纳扎基乳酸菌（LAB）分离株中的 164 株进行了鉴定，代表性菌株的鉴定结果与 16S rRNA 基因测序结果完全一致。MALDI-TOF MS 分析与 16S rRNA 基因测序相结合，共鉴定出库纳扎基 15 种 LAB 物种，其中最主要的物种为植物乳杆菌（40.46%）、魏斯氏菌（27.27%）和戊糖片球菌（15.00%）。对所有分离株进行表型筛选，发现有 57 株魏斯氏菌、9 株植物乳杆菌、1 株伴放线杆菌、1 株乳酸片球菌和 1 株柠檬明串珠菌能够产生葡聚糖和/或果聚糖。所有产 EPS 菌株均通过 PCR 检测到了葡聚糖蔗糖酶基因。魏斯氏菌 YKDIA1 和 YKDIA4 分别从小米-高粱粉水解物-蔗糖中生产出 11.93 和 11.70 g/L 的葡聚糖。利用魏斯氏菌 YKDIA1 生产的库纳扎基具有高持水能力（100%）和 49.46-139.24 mPas 范围的粘度。本研究采用 MALDI-TOF MS 高通量策略充分揭示了库纳扎基中的 LAB 物种组成，进一步证明了产 EPS 的 LAB 菌株的优势存在及其对库纳扎基流变特性的影响潜力。
