Unlocking the Genetic Secrets of a Bacteria's Glue Production

Jenn Hoskins
16th April, 2024

Unlocking the Genetic Secrets of a Bacteria's Glue Production

Image Source: Natural Science News, 2024

Key Findings

  • Researchers in East China identified two bacterial strains that efficiently produce γ-PGA, a biodegradable polymer
  • They pinpointed specific genes in these strains that are responsible for the synthesis and breakdown of γ-PGA
  • The study's genetic analysis may lead to improved methods for the sustainable production of γ-PGA
Poly-gamma-glutamic acid (γ-PGA) is a biopolymer with a high molecular weight, meaning it consists of large molecules made up of repeating units of the amino acid glutamic acid. This substance is notable for its versatility, being used in a variety of industries, from food to medicine to environmental engineering. Its appeal comes from its biodegradability and non-toxicity, making it an environmentally friendly alternative to synthetic polymers. The production of γ-PGA is a biological process, predominantly carried out by certain strains of bacteria, including Bacillus species. Researchers at the East China University of Science and Technology have taken a significant step in understanding how this production can be optimized[1]. By examining natto, a traditional Japanese food made by fermenting soybeans with Bacillus subtilis, they identified two strains, N3378-2at and N3378-3At, that are prolific producers of γ-PGA. The team delved into the genetic makeup of these strains, pinpointing the specific genes involved in the synthesis of γ-PGA. They identified a cluster of genes responsible for the production of this biopolymer, including the γ-PGA synthetase gene cluster (PgsB, PgsC, PgsA, YwtC, and PgdS), as well as other genes like the glutamate racemase RacE and enzymes that break down γ-PGA, such as phage-derived γ-PGA hydrolase (PghB and PghC) and exo-γ-glutamyl peptidase (GGT). Building on previous studies[2][3][4], the research expands our knowledge of the genetic components that Bacillus subtilis uses to produce γ-PGA. Earlier research had shown that manipulating the PgsBCA gene complex could lead to increased production of γ-PGA[2]. This new study adds to that understanding by identifying additional genes and proteins that play a role in the synthesis and degradation of γ-PGA. The researchers didn't stop at merely identifying these genes; they also performed genotyping analysis on sequences from the isolated Bacillus subtilis strains and 181 B. subtilis sequences obtained from GenBank, a database of publicly available DNA sequences. This analysis allowed them to classify the strains into five distinct types based on their γ-PGA-related protein sequences. Furthermore, the study discovered that B. amyloliquefaciens LL3, another bacterial species, could also produce γ-PGA. This led to the inclusion of B. velezensis and B. amyloliquefaciens strains from GenBank in the analysis, adding two more types to the classification system. The research culminated in the construction of evolutionary trees for these protein sequences, providing a visual representation of the relationships and diversity among the γ-PGA-producing strains. This comprehensive genetic and evolutionary analysis is crucial for the future development and utilization of γ-PGA-producing bacteria. By understanding the diversity and evolutionary history of these strains, scientists can better select or engineer bacteria for the efficient production of γ-PGA. This could lead to more cost-effective and sustainable production methods for this valuable biopolymer, potentially increasing its use and reducing our reliance on less environmentally friendly materials. The significance of this study lies in its potential impact on the commercial production of γ-PGA. With a clearer understanding of the genetic factors influencing γ-PGA synthesis, scientists and engineers can work towards overcoming the productivity and yield constraints that have limited its industrial application[3]. The findings may also inform the development of new biotechnological applications, such as the creation of γ-glutamyl derivatives with flavor-enhancing properties[4]. In summary, the researchers at the East China University of Science and Technology have provided valuable insights into the genetic basis for γ-PGA production in Bacillus strains. Their work lays the foundation for future efforts to harness the full potential of this remarkable biopolymer, with implications for a wide range of industries and environmental sustainability.



Main Study

1) Genomic characterization and related functional genes of γ- poly glutamic acid producing Bacillus subtilis

Published 15th April, 2024


Related Studies

2) Poly-L-gamma-glutamic acid production by recombinant Bacillus subtilis without pgsA gene.


3) Recent Advances in Microbial Synthesis of Poly-γ-Glutamic Acid: A Review.


4) pH-dependent hydrolase, glutaminase, transpeptidase and autotranspeptidase activities of Bacillus subtilis γ-glutamyltransferase.


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