Extraction, partial purification and characterisation of vanillic acid decarboxylase from Alicyclobacillus acidoterrestris DSM 3923.
BACKGROUND
Vanillic acid decarboxylase (VAD) is the key enzyme responsible for guaiacol production in Alicyclobacillus acidoterrestris; however, information related to this enzyme is currently unavailable. The aim of this study is to characterise the VAD from A. acidoterrestris.


RESULTS
Specific activity of VAD in vanillic acid-induced A. acidoterrestris DSM 3923 cells was highest in the early stage of the log phase, and almost undetectable in the stationary and death phases. Of the four techniques used to extract VAD, sonication was found to be the most effective and recovered 3.23 U mg(-1) of VAD. Through optimisation of the crucial parameters for sonication, the recovery of VAD had more than doubled (6.81 U mg(-1) ). The crude enzyme extract was purified by ammonium sulfate precipitation and a 9.87-fold purification was obtained. The partially purified VAD exhibited optimum activity at pH 6.0-6.5, 45°C and was stable at pH 5.0-7.5, 20-45°C. The Km and Vmax values of the VAD were 0.53 mmol L(-1) and 96 U mg(-1) protein, respectively. VAD activity was stimulated by Co(2+) and Mn(2+) , but was inhibited by Ni(2+) , Cu(2+) , Ba(2+) and Fe(3+) . Cinnamic acid, ferulic acid, resveratrol, quercetin and rutin at the concentration of 1 mmol L(-1) could completely inhibit the activity of VAD.


CONCLUSIONS
The present study provides the first report on the characteristics of the VAD from A. acidoterrestris, which will contribute to the development of more effective control methods to minimise A. acidoterrestris-related spoilage in fruit juices. © 2015 Society of Chemical Industry.
College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Rui
R
Cai
College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Dongyu
D
Li
College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Yahong
Y
Yuan
College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Zhouli
Z
Wang
College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Chunfeng
C
Guo
College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Bin
B
Liu
College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Tianli
T
Yue
D056450:Alicyclobacillus / Q000201:enzymology* / Q000378:metabolism / Q000648:ultrastructure; D002262:Carboxy-Lyases / Q000235:genetics / Q000378:metabolism*; D006139:Guaiacol / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D013696:Temperature; D014465:Ultrasonics; D014641:Vanillic Acid / Q000378:metabolism
D006139:Guaiacol; D002262:Carboxy-Lyases; D014641:Vanillic Acid
Alicyclobacillus acidoterrestris; characterisation; extraction; guaiacol; phenolic inhibitor; vanillic acid decarboxylase