Biotransformation of Isobutyraldehyde to Isobutanol by an Engineered Escherichia coli Strain

Introduction: biotransformation process has been used in various industries due to its ability to produce valuable chemicals and address environmental concerns. propylene hydroformylation is a process in which n-butyraldehyde and isobutyraldehyde are produced. n-butyraldehyde is a high valuable chemical with many industrial applications, while isobutyraldehyde produced as a by-product is an environmental pollutant. this study offers a biotechnological approach for conversion of isobutyraldehyde into a high-value substance. an engineered strain of escherichia coli was developed by genomic insertion of alcohol-dehydrogenase gene (adha) from lactococcus lactis which can convert isobutyraldehyde into isobutanol. materials and methods: the adha gene was engineered to substitute some of its amino acids to result in a more efficient enzyme. engineered gene was synthesized and introduced into e. coli genome to develop recombinant e. coli eg-296 strain. in addition, by using the qualiteck-4 software, 16 well-defined experiments (l16 orthogonal array) with two levels of seven variable parameters were used to optimize the process efficiency. results: the findings of this study revealed that the e. coli strain eg-296 is capable of converting isobutyraldehyde into isobutanol. the optimization results showed that optimum medium composition for the highest isobutanol production were 10 g/l glucose or glycerol as carbon source, 10 g/l nh4cl as nitrogen source, mid-log of inoculum age, and 1% inoculum volume in 25ml medium. after optimization, 560 mg/l isobutanol was produced from 600 mg/l isobutyraldehyde with 91% yield. conclusions: recombinant e. coli strain with a relatively optimum medium can be used to remove isobutyraldehyde in refineries or other industries producing this chemical as a by-product.