Optimization of fermentation conditions of aroma-producing endophytic bacteria in Ocimum×citriodorum and its application in cigarette flavoring

ZHAO Qiaoyue; LI Xinyan; WANG Liusheng; LIU Wei; MA Rong; FENG Wenning; LI Yuanyuan; ZHAO Mingqin

doi:10.12187/2026.01.011

Abstract：[Objective]This study aims to explore the aroma-producing potential of endophytic bacteria in Ocimum×citriodorum.[Methods]Traditional isolation and culture method combined with morphological and molecular biological method were used to screen and identify the dominant aroma-producing strains from its roots,stems and leaves;then,the fermentation conditions were optimized by the single factor test and response surface method;and volatile oil was extracted by simultaneous distillation extraction(SDE)and subjected to cigarette flavoring evaluation.[Results]A total of 38 strains of endophytic bacteria were isolated.Sensory evaluation confirmed that strain J-3-6 had the best aroma quality,which was identified as Pantoea ananatis exhibiting a sweet jasmine aroma with indole as the main aroma-producing substance.The optimal fermentation conditions were as follows:lactose mass concentration of 10.2 g/L,yeast extract powder mass concentration of 50.7 g/L,liquid volume of 259 mL,inoculation amount of 7%,initial pH value of 7,fermentation temperature of 26℃,shaker rotation speed of 180 r/min,and fermentation time of 48 h.Under these conditions,the indole yield was 5.53 times the initial yield.A total of 45 volatile organic compounds were identified in the fermentation system,mainly composed of alcohols,esters and heterocyclic compounds.The aroma characteristics were based on a fresh fruity aroma,integrated with complex floral and woody notes.Cigarette flavoring evaluation showed that the most suitable addition level was 4 μg/cigarette.[Conclusion]Optimization of the fermentation conditions for Pantoea ananatis J-3-6 by the response surface method significantly enhances indole production,and its metabolites extracted as volatile oils can effectively harmonize tobacco aroma and reduce the offensive odor and irritation of cigarettes.