A new concept of biocatalytic synthesis of acrylic monomers for obtaining water-soluble acrylic heteropolymers

Rhodococcus strains were designed as model biocatalysts (BCs) for the production of acrylic acid and mixtures of acrylic monomers consisting of acrylamide, acrylic acid, and N-alkylacrylamide (N-isopropylacrylamide). To obtain BC strains, we used, among other approaches, adaptive laboratory evolution (ALE), based on the use of the metabolic pathway of amide utilization. Whole genome sequencing of the strains obtained after ALE, as well as subsequent targeted gene disruption, identified candidate genes for three new amidases that are promising for the development of BCs for the production of acrylic acid from acrylamide. New BCs had two types of amidase activities, acrylamide-hydrolyzing and acrylamide-transferring, and by varying the ratio of these activities in BCs, it is possible to influence the ratio of monomers in the resulting mixtures. Based on these strains, a prototype of a new technological concept for the biocatalytic synthesis of acrylic monomers was developed for the production of water-soluble acrylic heteropolymers containing valuable N-alkylacrylamide units. In addition to the possibility of obtaining mixtures of different compositions, the advantages of the concept are a single starting reagent (acrylamide), more unification of processes (all processes are based on the same type of biocatalyst), and potentially greater safety for personnel and the environment compared to existing chemical technologies.

[Nucleotide sequence and structural analysis of cryptic plasmid pBL90 from Brevibacterium lactofermentum]

The nucleotide sequence of cryptic plasmid (designated as pBL90) detected in the cells of Brevibacterium lactofermentum DSM 1412 was determined. The length of plasmid DNA is 67826 bp. Comparison of the nucleotide sequence of pBL90 with known plasmid sequences showed no long regions of significant homology. Computer analysis of the plasmid DNA revealed 29 open reading frames (ORFs). The amino acid sequences of 15 ORFs (approximately 25% of plasmid length) have a high (>70%) level of identity to proteins from different plasmids of Corynebacterium representatives, including replicative proteins. Unusual in pBL90 is the presence of replicative genes from two different families and types of replication.