Biotransformation of Tobacco-Derived Z-Abienol into Pr ecursors of ambrox by Newly Identified Acinetobacter tj ernbergiae LSC-2

Gaolei Xi¹Qi Wenyuan²Aamir Rasool³Yongzhen Zhao¹Qingfu Wang¹Liuke Zhang¹Haoyang Chen¹Xinlong Zhang²Shen Huang^2*Zhifi Chen^1*

• ¹China Tobacco Henan Industrial Co., Ltd., Zhengzhou, Henan Province, China
• ²Zhengzhou University of Light Industry, Zhengzhou, China
• ³University of Balochistan, Quetta, Balochistan, Pakistan

Z-abienol, a labdane diterpene found in tobacco leaves, is a key precursor for producing valuable aroma compounds such as ambrox. This study aimed to ide ntify and characterize a bacterial strain capable of efficiently degrading Z-abien ol through microbial fermentation. The strain LSC-2, isolated from fresh tobacc o leaves, was identified as Acinetobacter tjernbergiae based on morphological f eatures and 16S rDNA phylogenetic analysis. Fermentation optimization experim ents determined that the highest degradation efficiency (69.3%) was achieved u nder 1 mg/mL Z-abienol, 0.5 mg/mL urea as the nitrogen source, pH 7, 30°C, and 150 rpm over four days. Whole-genome sequencing and functional annota tion revealed that oxidoreductases, particularly those in the auxiliary activity (A A) enzyme family, play a critical role in Z-abienol degradation. High-performan ce liquid chromatography and gas chromatography-mass spectrometry analysis c onfirmed the biotransformation of Z-abienol into several intermediates, including sclareol (211.3 μg/mL), scalaral (89.5 μg/mL), and amberonne (57.0 μg/mL).These intermediates have significant industrial applications, particularly in the fr agrance, pharmaceutical, and cosmetic industries. Sclareol serves as a key precu rsor for synthesizing ambrox, a widely used fixative in high-end perfumery, wh ile scalaral and amberonne enhance aroma in tobacco and flavor formulations.These findings provide valuable insights into the microbial degradation of Z-abienol, offering a sustainable approach for producing bio-based fragrance co mpounds. Future studies will focus on the enzymatic mechanisms and metaboli c engineering strategies to improve biotransformation efficiency.