PDF(Pubmed)
Abstract：
Pichia yeasts are capable of forming biofilms during vinegar production and causing spoilage in various beverages. In addition, there exists a significant likelihood of encountering yeast contamination which can prevent vinegar production. The present study investigates the detection and characterization of the Pichia manshurica (P. manshurica) biofilm on traditionally produced homemade apple vinegar. The unique characteristics of vinegar were analyzed with a focus on the constituent, known as the \"mother of vinegar\", whose composition is comprised of cellulosic biofilm and acetic acid bacteria, including Gluconobacter oxydans (G. oxydans) Briefly, P. manshurica was isolated from apple vinegar and characterized in terms of the effect of biofilm formation on the surface of the cellulosic film on vinegar production. Microbial identification of vinegar with/without contamination by P. manshurica was analyzed through MALDI-TOF mass spectrometry (MS), and biofilm was characterized by Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), and crystal violet staining. Accordingly, MS spectrum of isolates was identified as G. oxydans and P. manshurica with a ratio of 2.01 and 1.94, respectively. The FTIR analysis indicated that the peaks within the range of 1150-900 cm-1 revealed a high content of polysaccharide in P. manchuria-contaminated biofilm, which is attributed to the stretching vibration of C-C and C-O bonds. The spectral region from 2921.51 to 2853.71 cm-1 exhibited the characteristic of lipids in bacterial cell walls and membranes. SEM images of bacterial biofilms revealed a three-dimensional network composed of ultrafine fibers with a ribbon-like shape; however, the condensed reticulated structure was observed in contaminated biofilms. The presence of two microbial populations was detected regarding the morphological analysis. Crystal violet staining of contaminated-cellulosic biofilms visualized bacterial and yeast colonization. Concisely, this study emphasizes that the proliferation of Pichia during apple fermentation has the potential to adversely affect the quality of the homemade vinegar, due to its distinct biofilm characteristics.
摘要：
毕赤酵母能够在醋生产期间形成生物膜并在各种饮料中引起腐败。此外,有一个很大的可能性遇到酵母污染，可以防止生产醋。本研究调查了曼氏毕赤酵母（P.manshurica）传统生产的自制苹果醋上的生物膜。分析了醋的独特特性，重点是成分，被称为“醋之母”，其组成由纤维素生物膜和乙酸细菌组成，包括氧化葡糖杆菌(G.oxydans)简而言之，从苹果醋中分离出马尾松，并根据纤维素膜表面生物膜的形成对醋生产的影响进行表征。通过MALDI-TOF质谱（MS）分析了有/无污染的醋的微生物鉴定。通过傅里叶变换红外光谱(FT-IR)对生物膜进行表征,扫描电子显微镜（SEM），和结晶紫染色。因此，分离物的MS谱分别鉴定为氧化甘草和马尾松，比例分别为2.01和1.94。FTIR分析表明，在1150-900cm-1范围内的峰表明，在受P.满洲污染的生物膜中多糖含量高，这归因于C-C和C-O键的拉伸振动。从2921.51到2853.71cm-1的光谱区域表现出细菌细胞壁和细胞膜中脂质的特征。细菌生物膜的SEM图像显示了由带状超细纤维组成的三维网络；但是，在污染的生物膜中观察到浓缩的网状结构。关于形态学分析,检测到两种微生物群体的存在。受污染的纤维素生物膜的结晶紫染色使细菌和酵母定植可视化。简洁地说，这项研究强调，苹果发酵过程中毕赤酵母的增殖有可能对自制醋的质量产生不利影响，由于其独特的生物膜特征。
