Environmental comparison of biobased chemicals from glutamic acid with their petrochemical equivalents.

Glutamic acid is an important constituent of waste streams from biofuels production. It is an interesting starting material for the synthesis of biobased chemicals, thereby decreasing the dependency on fossil fuels. The objective of this paper was to compare the environmental impact of four biobased chemicals from glutamic acid with their petrochemical equivalents, that is, N-methylpyrrolidone (NMP), N-vinylpyrrolidone (NVP), acrylonitrile (ACN), and succinonitrile (SCN).

Synthesis of biobased succinonitrile from glutamic acid and glutamine.

Succinonitrile is the precursor of 1,4-diaminobutane, which is used for the industrial production of polyamides. This paper describes the synthesis of biobased succinonitrile from glutamic acid and glutamine, amino acids that are abundantly present in many plant proteins. Synthesis of the intermediate 3-cyanopropanoic amide was achieved from glutamic acid 5-methyl ester in an 86 mol% yield and from glutamine in a 56 mol % yield.

Mutation of His465 alters the pH-dependent spectroscopic properties of Escherichia coli glutamate decarboxylase and broadens the range of its activity toward more alkaline pH.

Glutamate decarboxylase (GadB) from Escherichia coli is a hexameric, pyridoxal 5'-phosphate-dependent enzyme catalyzing CO(2) release from the alpha-carboxyl group of L-glutamate to yield gamma-aminobutyrate. GadB exhibits an acidic pH optimum and undergoes a spectroscopically detectable and strongly cooperative pH-dependent conformational change involving at least six protons. Crystallographic studies showed that at mildly alkaline pH GadB is inactive because all active sites are locked by the C termini and that the 340 nm absorbance is an aldamine formed by the pyridoxal 5'-phosphate-Lys(276) Schiff base with the distal nitrogen of His(465), the penultimate residue in the GadB sequence.