Microbial strains and process for the manufacture of biomaterials

摘要

DNA constructs and genetically engineered microbial strains constructed using these DNA constructs, which produce a nuclease enzyme with specificity for DNA and/or RNA, are provided. These strains secrete nuclease into the periplasm or growth medium in an amount effective to enhance productivity and/or recovery of polymer, and are particularly suited for use in high cell density fermentation processes. These constructs are useful for modifying microbial strains to improve production and recovery processes for polymers such as intracellular proteins, such as enzymes, growth factors, and cytokines; for producing polyhydroxyalkanoates; and for producing extracellular polysaccharides, such as xanthan gum, alginates, gellan gum, zooglan, hyaluronic acid and microbial cellulose.

主权项

1. A bacterial strain producing polyhydroxyalkanoates wherein the bacterial strain is selected from the group consisting of Ralstonia eutropha, Pseudomonas putida and Escherichia coli and is genetically modified to express a heterologous nuclease gene integrated into the chromosome of the bacterial strain, wherein the nuclease is secreted into the periplasmic space and released when the bacteria is lysed in an amount effective to degrade in less than 24 hours at least 95% of all of the nucleic acid released following lysis of the cells.