Physiology of a Hybrid Pathway for Nicotine Catabolism in Bacteria

Abstract

Nicotine is a major N -heterocyclic aromatic alkaloid produced in tobacco plants and the main toxic chemical in tobacco waste. Due to its complex physiological effects and toxicity, it has become a concern both in terms of public health and the environment. A number of bacteria belonging to the genera Arthrobacter and Pseudomonas can degrade nicotine via the pyridine and pyrrollidine pathways. Recently, a novel hybrid of the pyridine and pyrrolidine pathways (also known as the VPP pathway) was found in the Rhizobiale group bacteria Agrobacterium tumefaciens S33, Shinella sp. HZN7 and Ochrobactrum sp. SJY1 as well as in other group bacteria. The special mosaic pathway has attracted much attention from microbiologists in terms of the study of their molecular and biochemical mechanisms. This will benefit the development of new biotechnologies in terms of the use of nicotine, the enzymes involved in its catabolism, and the microorganisms capable of degrading the alkaloid. In this pathway, some metabolites are hydroxylated in the pyridine ring or modified in the side chain with active groups, which can be used as precursors for the synthesis of some important compounds in the pharmaceutical and agricultural industries. Moreover, some enzymes may be used for industrial biocatalysis to transform pyridine derivatives into desired chemicals. Here, we review the molecular and biochemical basis of the hybrid nicotine-degrading pathway and discuss the electron transport in its oxidative degradation for energy conservation and bacterial growth.

An NAD-Specific 6-Hydroxy-3-Succinoyl-Semialdehyde-Pyridine Dehydrogenase from Nicotine-Degrading Agrobacterium tumefaciens Strain S33

“…2 ). In addition, the reaction rates with SAP as a substrate and the K m values for the substrates were comparable to those of other enzymes involved in nicotine degradation in strain S33 ( 22 ); these findings are sufficient to support Ald as participating in nicotine degradation in vivo . Furthermore, the disruption of the ald gene in strain S33 had a negative effect on the growth of strain S33 in nicotine medium but not in HSP medium ( Fig.…”

“…To clarify the biochemical mechanism of this special hybrid pathway, great efforts have been put into studies in recent years, including the analysis of its genome and transcriptome and the purification and characterization of its key enzymes ( 6 , 12 , 15 – 21 ). Now, a better understanding of the hybrid pathway has been achieved ( 22 ) after the key oxidoreductases involved in the pathway, including nicotine dehydrogenase (NdhAB), 6-hydroxynicotine oxidase (Hno), 6-hydroxypseudooxynicotine dehydrogenase (Pno), reactive imine deaminase (Rid), and 6-hydroxy-3-succinoylpyridine hydroxylase (Hsh), were purified and characterized ( Fig. 1A ) ( 15 – 18 , 20 , 21 ).…”

Cultivation and application of nicotine-degrading bacteria and environmental functioning in tobacco planting soil

“…In the pyrrolidine pathway represented by the Gram-negative bacteria Pseudomonas , the most important enzymes are nicotine oxidoreductase and 3-succinoylpyridine monooxygenase (Hu et al 2019 ; Xia et al 2018 ). A variant of the pyridine and pyrrolidine pathways, named the VPP pathway (Huang et al 2020 ), is found in the bacteria Agrobacterium sp. S33 (Shang et al 2021 ), Stenotrophomonas geniculata N1 (Liu et al 2014 ), and so on.…”

Bacillus sp. YC7 from intestines of Lasioderma serricorne degrades nicotine due to nicotine dehydrogenase

“…Within the gut of tobacco beetles, a diverse community of intestinal flora coexists, comprising various microorganisms such as bacteria and fungi. Studies have shown that certain strains of bacteria in the beetle’s gut possess the enzymatic machinery to break down nicotine into less harmful compounds (Huang et al 2020 ). This intricate microbial nicotine degradation pathway has caught the attention of researchers as a novel and biologically inspired approach to combat nicotine pollution.…”