为筛选具有特定生物转化功能的菌株，从柑橘果园取得土样，以生长曲线及转化瓦伦西亚橘烯生成圆柚酮的产量为指标，进行菌株的初筛和复筛。利用SPME-GC-MS技术，对菌株转化瓦伦西亚橘烯生成的产物种类及含量进行测定与分析；通过生理生化实验以及16S rDNA测序对所筛菌株进行菌种鉴定，结果表明所筛菌株为伯克霍尔德菌属，将其命名为Burkholderia sp. PZQ14。在LB培养基的基础上，以圆柚酮转化量为指标，进行培养基成分单因素试验，再通过响应面优化试验，探讨培养基成分不同质量浓度组合对圆柚酮转化量的影响。结果表明，最优培养基组分为：葡萄糖38 g/L，蛋白胨25 g/L，FeSO40.60 g/L。在此条件下进行验证试验，圆柚酮转化量为328.69±17.88 mg/L，转化率为35.73%±1.24%，相比LB培养基，圆柚酮转化量提高了251 mg/L。
Nootkatone is a typical aroma substance of citrus fruits,and valencene is often used as a precursor substance to produce nootkatone in industry. Compared with the method of physical extraction and chemical synthesis,the biotransformation method to produce nootkatone has the advantages of high specificity,speed and efficiency,and can be added to food and cosmetics. In order to screen strains with specific biotransformation functions,soil samples were obtained from citrus orchards,and the growth curve and the yield of the nootkatone produced by the transformation of valencene were used as indicators to carry out preliminary screening and re-screening of the strains. SPME-GC-MS was used to measure and analyze the types and contents of the products produced by valencene biotransformation. The results of physiological and biochemical tests and 16S rDNA sequencing showed that the screened strains were identified as Burkholderia sp.,which was named Burkholderia sp. PZQ14. On the basis of LB medium,the transformation amount of nootkatone was used as an indicator to carry out a single factor test of medium composition,and then the effect of the combination of different mass concentrations of the culture medium components on nootkatone yield was investigated by response surface optimization test. The results showed that the optimal medium components were as follows:glucose concentration of 38 g/L,peptone concentration of 25 g/L,and FeSO4 concentration of 0.60 g/L. The content of nootkatone was 328.69±17.88 mg/L and the transformation ratio was 35.73%±1.24% when three validation tests were conducted under these conditions. The nootkatone yield increased by 251 mg/L and the transformation ratio increased by 27.30% compared with LB medium. It will provide a new way to increase the yield of nootkatone and lay a theoretical foundation for the further industrial production of nootkatone.