Department of Pharmacy, State University of Maringá-UEM, Av. Colombo 5790, Maringá-PR 87020-900, Brazil.
Molecules. 2012 Aug 8;17(8):9476-88. doi: 10.3390/molecules17089476.
The preservation of Bacillus firmus strain 37 cells by lyophilization was evaluated and response surface methodology (RSM) was used to optimize the β-cyclodextrin (β-CD) production by cells immobilized on loofa sponge. Interactions were studied with the variables temperature, pH and dextrin concentration using a central composite design (CCD). Immobilization time influence on β-CD production was also investigated. B. firmus strain 37 cells remained viable after one year of storage, showing that the lyophilization is a suitable method for preservation of the microorganism. From the three-dimensional diagrams and contour plots, the best conditions for β-CD production were determined: temperature 60 °C, pH 8, and 18% dextrin. Considering that the amount of dextrin was high, a new assay was carried out, in which dextrin concentrations of 10, 15, and 18% were tested and the temperature of 60 °C and pH 8 were maintained. The results achieved showed very small differences and therefore, for economic reasons, the use of 10% dextrin is suggested. Increasing the immobilization time of cells immobilized on synthetic sponge the β-CD production decreased and did not change for cells immobilized on loofa sponge. The results of this research are important for microorganism preservation and essential in the optimization of the biosynthesis of CD.
通过冷冻干燥法保存 Firmus 芽孢杆菌 37 细胞，并使用响应面法（RSM）优化固定在丝瓜络海绵上的细胞生产 β-环糊精（β-CD）。使用中心复合设计（CCD）研究了温度、pH 值和糊精浓度等变量之间的相互作用。还研究了固定化时间对 β-CD 生产的影响。Firmus 芽孢杆菌 37 细胞在一年的储存后仍保持存活，表明冷冻干燥是保存微生物的一种合适方法。从三维图和等高线图可以确定 β-CD 生产的最佳条件：温度 60°C、pH 值 8 和 18%糊精。考虑到糊精的用量较高，进行了一项新的实验，其中测试了 10%、15%和 18%的糊精浓度，并保持 60°C 的温度和 pH 值 8。结果表明差异非常小，因此，出于经济原因，建议使用 10%的糊精。增加固定在合成海绵上的细胞的固定化时间会降低β-CD 的产量，而固定在丝瓜络海绵上的细胞的产量则不会改变。这项研究的结果对微生物的保存非常重要，并且对 CD 的生物合成优化至关重要。
