Laboratory of Industrial Microbiology and Food Biotechnology, Institute of Biology, University of Latvia, Ojara Vaciesa Street 4, LV-1004, Riga, Latvia.
Institute of Polymer Materials, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena Street 3/7, LV-1048, Riga, Latvia.
Appl Microbiol Biotechnol. 2022 Nov;106(22):7449-7460. doi: 10.1007/s00253-022-12213-5. Epub 2022 Oct 7.
Biomaterials and biopolymers, such as bacterial cellulose (BC), are becoming increasingly important as sustainable materials with a wide range of potential applications. However, BC industrial production is associated with several difficulties such as low BC production yields and high production costs; therefore, cheap alternative growth media, e.g. apple juice are being studied intensively. The aim of this study is to evaluate BC synthesis under static conditions on apple juice medium (AJM). The optimal concentration of apple juice in unsupplemented AJM for Novacetimonas hansenii MSCL 1646 was shown by its dilution 1:6 with water, which resulted in 0.89 ± 0.01 g/L of dry BC weight after 10 cultivation days. Low BC synthesis can be associated with insufficient N concentration in apple juice; therefore, different organic and inorganic N sources were evaluated in combination with AJM, and beef extract (5 g/L) was found to be the most suitable. Further, AJM optimisation experiment showed the optimal apple juice and beef extract concentrations as 1:2 and 15 g/L respectively, which resulted in 17.27 ± 0.07 g/L of dry BC weight, which is significantly higher than in standard Hestrin-Schramm (HS) medium (4.07 ± 0.02 g/L). Analysis of mechanical and physical properties showed that use of AJM results in changes in BC properties compared with the standard HS medium. Results of the study indicate that apple juice is an effective and cheap C source that in combination with appropriate N source leads to high BC synthesis and makes it suitable for industrial BC production. KEY POINTS: • Low quality apples can be used as raw material for BC production; • Beef extract improves BC synthesis in apple juice medium; • Use of apple juice and beef extract affect mechanical properties of BC.
生物材料和生物聚合物，如细菌纤维素（BC），作为具有广泛应用潜力的可持续材料变得越来越重要。然而，BC 的工业生产存在一些困难，例如 BC 产量低和生产成本高；因此，人们正在积极研究廉价的替代生长培养基，例如苹果汁。本研究旨在评估静态条件下在苹果汁培养基（AJM）上合成 BC。通过将苹果汁稀释 1:6 与水混合，Novacetimonas hansenii MSCL 1646 在未添加 AJM 的最佳苹果汁浓度为 0.89±0.01 g/L 的干 BC 重量，培养 10 天后。BC 低合成可能与苹果汁中 N 浓度不足有关；因此，评估了不同的有机和无机 N 源与 AJM 的组合，发现牛肉提取物（5 g/L）最适合。此外，AJM 优化实验表明，最佳的苹果汁和牛肉提取物浓度分别为 1:2 和 15 g/L，可获得 17.27±0.07 g/L 的干 BC 重量，显著高于标准 Hestrin-Schramm（HS）培养基（4.07±0.02 g/L）。机械和物理性能分析表明，与标准 HS 培养基相比，使用 AJM 会导致 BC 性能发生变化。研究结果表明，苹果汁是一种有效的廉价 C 源，与合适的 N 源结合可实现高 BC 合成，使其适合工业 BC 生产。要点：• 低质量的苹果可用作 BC 生产的原料；• 牛肉提取物可提高苹果汁培养基中的 BC 合成；• 苹果汁和牛肉提取物的使用会影响 BC 的机械性能。
