Key Laboratory of Translational Tumor Medicine in Fujian Province, School of Basic Medicine Science, Putian University, Putian City, 351100, Fujian Province, China.
School of Pharmacy, Fujian Medical University, Fuzhou City, 350004, Fujian Province, China.
Appl Microbiol Biotechnol. 2023 Mar;107(5-6):1551-1562. doi: 10.1007/s00253-023-12407-5. Epub 2023 Feb 1.
In this study, loquat extract was selected as a promising substrate for bacterial cellulose (BC) production. A new BC-producing bacterial strain was isolated from residual loquat and identified as Komagataeibacter rhaeticus. BC production with different carbon sources and with loquat extract was investigated. Among all tested carbon sources, glucose was demonstrated to be the best substrate for BC production by K. rhaeticus, with up to 7.89 g/L dry BC obtained under the optimal initial pH (5.5) and temperature (28 °C) with 10 days of fermentation. The total sugar and individual sugars were investigated in different loquat extracts, in which fructose, glucose, and sucrose were the three main sugars. When loquat extract was prepared with a solid‒liquid (S-L) ratio of 2:1, the concentrations of glucose, fructose, and sucrose were 7.91 g/L, 9.31 g/L, and 2.84 g/L, respectively. The BC production obtained from loquat extract was higher than that of other carbon sources except glucose, and 6.69 g/L dry BC was obtained from loquat extract with an S-L ratio of 2:1. After BC production, all sugars substantially decreased, with the utilization of glucose, fructose, and sucrose reaching 93.9%, 87.9%, and 100%, respectively. These results suggested that the different sugars in loquat extract were all carbon sources participating in BC production by K. rhaeticus. Structural and physicochemical properties were investigated by SEM, TGA, XRD, and FT-IR spectroscopy. The results showed that the structural, chemical group, and water holding capacity of BC obtained from loquat extract were similar to those of BC obtained from glucose, but the crystallinity and thermal stability of BC were higher than those of BC from mannose and lactose but lower than those of BC from glucose and fructose. KEY POINTS: • A new BC-producing strain was isolated and identified as Komagataeibacter rhaeticus. • Loquat extract is an alternative substrate for BC production. • The BC obtained from loquat extract owns advanced physicochemical properties.
在这项研究中，批杷提取物被选为生产细菌纤维素（BC）的有前途的基质。从剩余的批杷中分离出一种新的 BC 生产菌株，并鉴定为罗伊氏固氮菌。研究了不同碳源和批杷提取物对 BC 生产的影响。在所有测试的碳源中，葡萄糖被证明是罗伊氏固氮菌生产 BC 的最佳底物，在最佳初始 pH（5.5）和温度（28°C）下，发酵 10 天可获得高达 7.89 g/L 的干 BC。研究了不同批杷提取物中的总糖和单糖，其中果糖、葡萄糖和蔗糖是三种主要糖。当批杷提取物的固液比（S-L）为 2:1 时，葡萄糖、果糖和蔗糖的浓度分别为 7.91 g/L、9.31 g/L 和 2.84 g/L。从批杷提取物中获得的 BC 产量高于除葡萄糖以外的其他碳源，而从 S-L 比为 2:1 的批杷提取物中获得 6.69 g/L 的干 BC。BC 生产完成后，所有糖的含量都大幅下降，葡萄糖、果糖和蔗糖的利用率分别达到 93.9%、87.9%和 100%。这些结果表明，批杷提取物中的不同糖都是罗伊氏固氮菌参与 BC 生产的碳源。通过 SEM、TGA、XRD 和 FT-IR 光谱对结构和物理化学性质进行了研究。结果表明，从批杷提取物中获得的 BC 的结构、化学基团和持水能力与从葡萄糖中获得的 BC 相似，但从批杷提取物中获得的 BC 的结晶度和热稳定性高于从甘露糖和乳糖中获得的 BC，但低于从葡萄糖和果糖中获得的 BC。 关键点： • 分离并鉴定出一种新的 BC 生产菌株，鉴定为罗伊氏固氮菌。 • 批杷提取物是 BC 生产的替代基质。 • 从批杷提取物中获得的 BC 具有先进的物理化学性质。
