Elucidation of the arecoline catabolism by Arthrobacter sp. strain NyZ413

Arecoline, the main active ingredient in the widely consumed addictive substance areca nut, is known for its genotoxicity and cytotoxicity. It would be helpful to know whether environmental microbes can degrade the toxic arecoline. Here, an arecoline degrader Arthrobacter sp. strain NyZ413 was isolated and characterized from areca palm soil, utilizing arecoline as its sole carbon source for growth. Strain NyZ413 exhibited a robust growth even at high 20 mM arecoline, and optimally degraded 1 mM arecoline at 30°C. High performance liquid chromatography and liquid chromatography-mass spectrometry analyses indicated that acecainide and guvacine were intermediates derived from arecoline degradation by strain NyZ413. Degradation of arecoline and arecaidine by strain NyZ413 was shown to be inducible, whereas guvacine degradation was constitutive. The genome of strain NyZ413 consists of a 4.4 Mbp chromosome and a 246 Kbp mega-plasmid. Genomic and transcriptomic analyses proposed that the gene cluster A involved in arecoline degradation was located on the mega-plasmid. In addition, detoxification experiments showed that biodegradation by strain NyZ413 completely eliminated the embryotoxic effects of arecoline on zebrafish, confirming its high biosafety and potential for bioremediation in arecoline-contaminated environments. This study fills the gap in our understanding of microbial degradation of arecoline and also provides a bacterial resource for bioremediation of arecoline-polluted sites.