UV and chemically induced Halomonas smyrnensis mutants for enhanced levan productivity

Erkorkmaz B. A., Kirtel O., Abaramak G., Nikerel E., TOKSOY ÖNER E.

JOURNAL OF BIOTECHNOLOGY, cilt.356, ss.19-29, 2022 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 356
  • Basım Tarihi: 2022
  • Doi Numarası: 10.1016/j.jbiotec.2022.07.005
  • Dergi Adı: JOURNAL OF BIOTECHNOLOGY
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Aquatic Science & Fisheries Abstracts (ASFA), BIOSIS, Biotechnology Research Abstracts, CAB Abstracts, Chemical Abstracts Core, Communication Abstracts, Compendex, EMBASE, Environment Index, Food Science & Technology Abstracts, INSPEC, MEDLINE, Metadex, Veterinary Science Database, Civil Engineering Abstracts
  • Sayfa Sayıları: ss.19-29
  • Anahtar Kelimeler: Levan, Halomonas smyrnensis, Poly(3-hydroxybutyrate), Halophile, Random mutagenesis, Osmoregulation, TRIPARTITE TRICARBOXYLATE TRANSPORTER, PERIPLASMIC-BINDING-PROTEIN, MULTILAYER FILMS, MICROBIAL LEVAN, SULFATED LEVAN, EXOPOLYSACCHARIDE, SYSTEMS, BIOSYNTHESIS, IMPROVEMENT, BACTERIUM
  • Marmara Üniversitesi Adresli: Evet

Özet

Halomonas smyrnensis AAD6(T) is a moderately halophilic bacterium proven to be a powerful biotechnological tool with its ability to accumulate valuable biopolymers such as levan and poly(3-hydroxybutyrate) (PHB). Levan is a fructose homopolymer with beta-2,6 fructofuranosidic linkages on the polymer backbone, and its distinctive ap-plications in various industries such as food, pharmaceutical, medical, and chemical have been well-defined. On the other hand, PHB is a promising raw material to produce biodegradable plastics. Although it was shown in our previous studies that H. smyrnensis AAD6(T) exhibits one of the highest conversion yields of sucrose to levan re-ported to date, novel strategies are required to overcome high costs of levan production. In this study, we aimed at increasing levan productivity of H. smyrnensis AAD6(T) cultures using random mutagenesis techniques combined (i.e., ethyl methanesulfate treatment and/or ultraviolet irradiation). After several consecutive treatments, mutant strains BAE2, BAE5 and BAE6 were selected as efficient levan producers, as BAE2 standing out as the most efficient one not only in sucrose utilization and levan production rates, but also in final PHB concentrations. The mutants' whole genome sequences were analysed to determine the mutations occurred. Several mutations in genes related to central carbon metabolism and osmoregulation were found. Our results suggest that random mutagenesis can be a facile and efficient strategy to enhance the performance of extremophiles in adverse conditions.