Purification and characterization of α‐acetolactate decarboxylase (ALDC) from newly isolated Lactococcus lactis DX. (2nd September 2014)

• Record Type: Journal Article
• Authors: Guo, Yuxing; Pan, Daodong; Ding, Haibing; Wu, Zhen; Sun, Yangying; Zeng, Xiaoqun
• Is Part Of: Journal of the science of food and agriculture. Volume 95:Number 8(2015:Jun. 15)
• Page Start: 1655
• Page End: 1661
• Publication Date: 2014-09-02
• Subjects: Food -- Periodicals; Agriculture -- Periodicals; 664
• DOI: 10.1002/jsfa.6868
• Languages: English
• ISSNs: 0022-5142

Abstract

<abstract abstract-type="main" id="jsfa6868-abs-0001"> <title>Abstract</title> <sec id="jsfa6868-sec-0001" sec-type="section"> <title>BACKGROUND</title> <p id="jsfa6868-para-0001">Diacetyl (2, 3‐butanedione) is a common flavor aroma from fermented dairy products. There is a need to screen new microorganisms that can efficiently produce large amounts of diacetyl.</p> </sec> <sec id="jsfa6868-sec-0002" sec-type="section"> <title>RESULTS</title> <p id="jsfa6868-para-0002">A new lactic acid bacterium that produced high concentrations of diacetyl was identified based on Gram staining, microscopic examination and 16S rDNA sequence analysis as <italic>Lactococcus lactis</italic> DX. Its <italic>α</italic>‐acetolactate decarboxylase (ALDC) was purified using 0.45 g mL<sup>−1</sup> ammonium sulfate precipitation, Sephacryl S‐300 and S‐200 HR and native‐PAGE. The purified ALDC displayed a monomer structure and had a molecular mass of about 73.1 kDa, which was estimated using SDS‐PAGE. IR analysis showed that the ALDC had a typical protein structure. The optimal temperature and pH for ALDC activity were 40 °C and 6.5 respectively. The ALDC of <italic>L. lactis</italic> DX was activated by Fe<sup>2+</sup>, Zn<sup>2+</sup>, Mg<sup>2+</sup>, Ba<sup>2+</sup> and Ca<sup>2+</sup>, while Cu<sup>2+</sup> significantly inhibited ALDC activity. Leucine, valine and isoleucine activated the ALDC.</p> </sec> <sec id="jsfa6868-sec-0003" sec-type="section"> <title>CONCLUSION</title> <p id="jsfa6868-para-0003">A strain that had high ability to produce diacetyl was identified as <italic>L. lactis</italic> DX. The difference in diacetyl production may be due to the ALDC, which is different from other ALDCs. © 2014 Society of Chemical Industry</p> </sec> </abstract>