Aerobic production of isoamyl acetate by overexpression of the yeast alcohol acetyl-transferases AFT1 and AFT2 in Escherichia coli and using low-cost fermentation ingredients

• Published in: Bioprocess and biosystems engineering 2008-06, Vol.31 (4), p.299-306
• Main Authors: Singh, R., Vadlani, P. V., Harrison, M. L., Bennett, G. N., San, K.-Y.
• Format: Article
• Language: English
• Subjects: Aerobiosis; Bioengineering; Biological and medical sciences; Bioreactors - economics; Bioreactors - microbiology; Biotechnology; Cell Culture Techniques - economics; Cell Culture Techniques - methods; Chemicals; Chemistry; Chemistry and Materials Science; E coli; Environmental Engineering/Biotechnology; Enzymes; Escherichia coli; Escherichia coli - metabolism; Fermentation; Food Science; Fundamental and applied biological sciences. Psychology; Genetic Enhancement - methods; Industrial and Production Engineering; Industrial Chemistry/Chemical Engineering; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Original Paper; Pentanols - economics; Pentanols - metabolism; Protein Engineering - methods; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Sorghum; Trans-Activators - genetics; Trans-Activators - metabolism; Transcription Factors - genetics; Transcription Factors - metabolism; Yeast; Yeasts
• ISSN: 1615-7591; 1615-7605
• DOI: 10.1007/s00449-007-0159-3

Isoamyl acetate, produced via fermentation, is a natural flavor chemical with applications in the food industry. Two alcohol acetyltransferases from Saccharomyces cerevisiae ( ATF1 and ATF2 ) can catalyze the esterification of isoamyl alcohol with acetyl coenzyme A. The respective genes were cloned and expressed in an appropriate ack-pta − strain of Escherichia coli . The engineered strains produce isoamyl acetate when isoamyl alcohol is added to the culture medium. Aerobic shake flask experiments examined isoamyl acetate production over various growth times, temperatures, and initial optical densities. The strain carrying the pBAD-ATF1 plasmid exhibited a high molar ester yield from glucose (1.13) after 48 h of aerobic growth at 25 °C. Low-cost media components, such as fusel oil, sorghum glucose and corn steep liquor, were found to give a high yield of isoamyl acetate. High-cell-density gave an increased isoamyl acetate yield of 0.18 g/g of glucose consumed.