Process optimization and kinetic evaluation for biosynthesis of D-isoascorbyl stearate

Bioprocess Biosyst Eng. 2015 May;38(5):833-9. doi: 10.1007/s00449-014-1326-y. Epub 2014 Nov 19.

Abstract

The synthesis of D-isoascorbyl stearate from D-isoascorbic acid and stearic acid with immobilized lipase (Novozym(®)435) as catalyst was studied. Response surface methodology and Box-Behnken design with six variables and three levels were employed to evaluate the effects of processing conditions on the conversion of D-isoascorbic acid. The results confirmed that the response surface method and statistical analysis were proved to be useful in developing optimal conditions for D-isoascorbyl stearate synthesis. The optimum conditions were predicted as follows: reaction temperature 48 °C, reaction time 17.7 h, immobilized lipase amount 50.0 % (w/w, of D-isoascorbic acid), substrate molar ratio 9:1 (stearic acid to D-isoascorbic acid), D-isoascorbic acid concentration 0.14 mol/L (based on solvent), 4A molecular sieve addition 200 g/L (based on solvent), and the optimal conversion was 90.6 %. Through the kinetics model fitting of the esterification, it was considered that the esterification conformed to a Ping-Pong bi-bi kinetic model with D-isoascorbic acid inhibition, and the obtained kinetic constants showed that the inhibition of D-isoascorbic acid and the enzyme affinity to substrate were abate with the increase of the reaction temperature.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ascorbic Acid / biosynthesis*
  • Biocatalysis
  • Candida / enzymology
  • Enzymes, Immobilized / chemistry*
  • Esterification
  • Fungal Proteins
  • Industrial Microbiology*
  • Kinetics
  • Lipase / chemistry
  • Solvents / chemistry
  • Stearic Acids / chemistry*
  • Surface Properties
  • Temperature

Substances

  • Enzymes, Immobilized
  • Fungal Proteins
  • Solvents
  • Stearic Acids
  • isoascorbic acid
  • stearic acid
  • Novozyme 435
  • Lipase
  • Ascorbic Acid