Synthesis Of Acetoin Nitrogen-containing Heterocyclic And Ester Derivatives

Acetoin is widely used as food flavor additive and in chemical synthesis as platform chemicals.Acetoin and its derivatives are frequently detected in the component analysis of a variety of foods.In recent years,there are many research about the biosynthesis of acetoin,but less research on synthesis of these derivatives.In this study,acetoin and its derivatives have been researched from the following three aspects.A novel temperature-controlled two-step preparation method of TTMP has been devised.In the first step,30.1 g/L acetoin was biosynthesied by Bacillus subtilis CICC10211.In the following step,the fermentation broth,supplemented with 67.7 g/L of diammonium phosphate,was transferred into another reactor controlled at 95°C.After 2.5h spontaneous reaction,8.34 g/L of TTMP was obtained.The novel method gives the highest product titre and production efficiency so far devised for TMP production from renewable materials,and give support which acetoin to TMP are nonenzymatic spontaneous reactions.Ten acetoin fatty acid esters（AFAEs）were synthesized by the esterification of acetoin and fatty acids catalyzed by immobilized Candida antarctica lipase B（CALB）.This is the first report of a biosynthetic approach for the production of AFAEs.Operational conditions including enzymes,substrates and their ratios,reaction time,temperature,solvents,and enzyme reuse times were examined.CALB has been shown to be effective for the lipase-catalyzed esterification of acetion and C₄–C₁₂ straight chain fatty acids.Higher temperatures,40–60℃,and higher acetoin/fatty acid molar ratios favored the conversion.The maximum yield of acetoin octanoate obtained was 50.7%.The enzyme activity declined at a steadyrate during reuse at 60°C and after the 10th cycle,65%of initial activity was still be retained.Acetoin fermentation production from refined sugar may not be economically,but using the hydrolysate of corn flour fermentation can directly reduce the cost.The experiments were carried with the strain Bacillus sp.H15-1,isolated previously from a rusted steel wirerope in Jiaozhou Bay,China.Dry-milled degermed maize was hydrolyzed by enzyme hydrolysis,as carbon source.Culture medium was optimized by Plackett-Burman design.The influences of different agitation speeds on acetoin production were investigated.The optimal medium was as follows:corn steep liquor powder 10 g/L,KH₂PO₄ 3 g/L,CH₃COONa 0.3 g/L,CaCl₂ 0.2 g/L and MgSO₄ 0.1 g/L is added to hydrolysate of corn flour.Fermentation using this medium,50.8 g/L of acetoin was obtained,the highest reported in thermophilic bacteria strains.