title: Enzymatic synthesis of aroma acetoin fatty acid esters by immobilized Candida antarctica lipase B.
abstract: OBJECTIVE
  To enzymatically synthesize aroma acetoin fatty acid esters, useful as flavor and fragrance ingredients in foods.
  
  
  RESULTS
  Immobilized Candida antarctica lipase B (CALB), performed significantly better than lipases from Rhizopus niveus and Candida rugosa in carrying out the esterification of acetoin and fatty acids. C4-C12 straight chain fatty acids were suitable acyl donors and CALB had a strong preference for longer straight chains up to ten carbon atoms. Higher temperatures, 40-60 °C, and higher acetoin/fatty acid molar ratios favored the conversion. The maximum yield of acetoin octanoate obtained was (51 ± 1) % after 24 h reaction time in hexane with 0.25 M octanoic acid, 5:1 excess acetoin and an enzyme concentration of 6 g/mol fatty acid at 60 °C. The enzyme activity declined at a steady rate during reuse at 60 °C and after the 10th cycle, 65 % of initial activity was still be retained.
  
  
  CONCLUSIONS
  This is the first report of acetoin fatty acid ester synthesis by biological method and CALB has been shown to be effective for the lipase-catalyzed esterification of acetion and C4-C12 straight chain fatty acids.
authors: Center for Bioengineering and Biotechnology, China University of Petroleum, No. 66 Changjiang West Road, Huangdao District, Qingdao, 266580, People's Republic of China, zjxiao@upc.edu.cn.
authors: Zijun
authors: Z
authors: Xiao
authors: Xiaoyuan
authors: X
authors: Hou
authors: Xin
authors: X
authors: Lyu
authors: Jing-Yi
authors: JY
authors: Zhao
authors: Lijun
authors: L
authors: Xi
authors: Jing
authors: J
authors: Li
authors: Jian R
authors: JR
authors: Lu
mesh_terms: D000093:Acetoin / Q000378:metabolism*; D004800:Enzymes, Immobilized / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism*; D005421:Flavoring Agents / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D008049:Lipase / Q000378:metabolism*; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D005227:Fatty Acids; D005421:Flavoring Agents; D005656:Fungal Proteins; D000093:Acetoin; D008049:Lipase; C431349:lipase B, Candida antarctica