产聚β-羟基丁酸芽孢杆菌的拉曼光谱快速筛选研究

Rapid Screening of Poly-β-hydroxybutyrate Producing Bacillus by Using Raman Spectroscopy

【目的】探索快速筛选产生物塑料聚β-羟基丁酸(PHB)芽孢杆菌的光学手段,以期筛选到以葡萄糖或蔗糖为发酵底物的高产PHB优良菌株。【方法】应用拉曼光镊技术快速收集分离株的单个细胞拉曼光谱,分析其光谱特征。【结果】基于拉曼光谱特征峰可快速辨别细胞类型和细胞PHB含量,菌落细胞的PHB拉曼信号强度与菌株的PHB发酵能力有相关性;从不同土壤样品中分离的菌株,45%以上具有产PHB的能力,其中S-C-2菌株在3%蔗糖下PHB最大产量为5.27g/L,PHB占细胞干重70%;拉曼光谱监测发酵过程显示,不同发酵阶段发酵液的PHB总含量与单个芽孢杆菌细胞1732cm^(-1)峰的平均信号强度线性相关。【结论】拉曼光谱可以简单快速分选产PHB的芽孢杆菌,实时监测PHB发酵进程。

【Objective】A new method for rapid screening poly- hydroxybutyrate(PHB)producing Bacillus strains was established by means of novel optical technique.【Methods】Raman tweezers technique was used to acquire the single-cell Raman spectra of isolates and to monitor the accumulation of PHB during further laboratory cultivation.【Results】The cell types and PHB content of individual cells were quickly distinguished based on the Raman characteristic peaks and Raman intensities.The averaged Raman intensities at peak 1732cm^(-1) of single-cell from plate colonies showed a certain correlation with the capacity of PHB fermentation.Overβ-one hundred randomly chosen strains were isolated from 4 soil samples and tested by Raman spectroscopy,of which more than 45%exhibited the ability to produce PHB.Among them,strain S-C-2accumulated up to 5.27g/L of PHB(70% of the cell dry weight)when incubated with 3% sucrose.During the flask cultivation,the averaged intensities of single cell at peak 1732cm^(-1) was linearly related with theyields of PHB(R2=0.91).【Conclusion】Raman spectroscopy can be considered as a fast and novel optical technique for screening of PHB-producing Bacillus and real-time monitoring of PHB fermentation processes.