In addition, a set of 11 enzymes described as closed circles in Table1 including 5-assingned cellulases, 5-assingned hemicellulases, and 1-assingned other protein identified in all culture conditions were the same enzymes produced by cultivation with cellobiose (disaccharide made from units of glucose), which is the simplest substrate.
Initial investigations focused on the hydrogenation of acetone (the simplest substrate previously examined under anhydrous conditions).
Glycerol kinase has the simplest substrate in this group and catalyzes a reaction of glycerol metabolism that is common to bacteria, archaea, and eukaryotes; this enzyme is widespread in representatives of all three domains of life.
We establish a microbial biosynthetic pathway for PAA production from the simple substrate phenylalanine in E. coli with heterologous coexpression of aminotransferase (ARO8), keto acid decarboxylase (KDC) and aldehyde dehydrogenase H (AldH) gene.
These mechanisms range from the simple (substrate availability, thermodynamic properties of reactions, feedback inhibition, and organelle localization) to the elaborate (formation of multienzyme complexes and thiol-based redox switches).
In this study, we establish a microbial biosynthetic pathway for PAA production from the simple substrate phenylalanine through overexpression of an aminotransferase gene ARO8, a keto acid decarboxylase gene KDC from S. cerevisiae and an aldehyde dehydrogenase H gene aldH from E. coli in E. coli (Fig. 1).
Studies on the control of catabolic genes related to the metabolism of simple substrates (such as glucose) performed in model organisms have revealed very complex GRN, thus, an even more sophisticated network controlling catabolic functions related to the metabolism of complex substrates, such as cellulose, could have been anticipated [ 32].
In conclusion, this study points to different metabolic routes being followed by a mixed anaerobic community, even in the mineralization of simple substrates like lactate.
For example, interfacially adsorbed derivative was the most active using simple substrates (ethyl butyrate) while PEI derivative was the most active hydrolysing ionic substrates (2-phenyl-2-butyroylacetic acid at pH 7) or methyl mandelate.
VA is the simple nonphenolic substrate used to estimate both LiP and VP activities in white-rot fungi.
