A comprehensive review on mutan (a mixed linkage of α-1-3 and α-1-6 glucans) from bacterial sources

ABSTRACT

Mutan is an extracellular sticky polymer having α-1-3 and α-1-6 glycosidic linkages with a large diversity in molecular weights and structures depending on the source. These compounds are reported to be highly thermostable and also have potential physiochemical and biological applications. The main aim of this review is to provide an overview of glucosyltransferases and their role in mutan synthesis. The production strategies and structural properties of bacterial mutans are discussed with a goal to improve production efficiency. The physicochemical features, chemical modifications, potential industrial applications and future prospects are also discussed. According to data, mutan and its derivatives will play a larger role in medicinal sectors and as thermoplastics in the near future.

Abbreviations: ABTS: 2,2ʹ-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid; BHI: Brain heart infusion broth; ¹³C (HSQC) NMR: Heteronuclear Single Quantum Coherence NMR; CBMs: Carbohydrate binding modules; DPPH: 2,2-diphenyl-1-picrylhydrazyl; FTIR: Fourier-transform infrared spectroscopy; GC–MS: Gas chromatography-mass spectrometry; GPC: Gel permeation chromatography; Gtfs: Glucosyltransferases; ¹H (DQF-COSY): Double-quantum filtered correlation spectroscopy; HPAEC-PAD: High-performance anion exchange chromatography with pulsed amperometric detection; HPLC: High performance liquid chromatography; HPSEC-RI: High-performance size exclusive chromatography coupled with refractive index; HPSEC-MALLS: High-performance size exclusive chromatography with multi-angle laser light scattering detection; MALDI-TOF: Matrix-Assisted Laser Desorption/Ionization-Time of Flight mass spectrometry; M_w: Weight-average molecular weight; MWD: Molecular weight distribution; NMR: Nuclear magnetic resonance spectroscopy; TEM: Transmission electron microscopy; THB: Todd Hewitt Broth; TTY: Tryticase tryptose yeast extract broth.

KEYWORDS:

• Mutan
• Streptococcal
• glucosyltransferases
• structure
• production process
• value-added products

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Department of Science and Technology-WosA[SR/WOS-A/LS-479/2017].

Notes on contributors

Sirisha Boddapati

Dr. Sirisha Boddapati is currently working as women scientist Wos A in Department of Biotechnology at Indian Institute of Technology-Madras. Her research interest include biomaterial synthesis, protein biochemistry, production of proteins and enzymes with therapeutic and industrial applications.

Sathyanaryana N. Gummadi

Dr. Sathyanaryana N. Gummadi is currently a professor in Department of Biotechnology at Indian Institute of Technology-Madras. He has published more than 150 papers in peer-reviewed international and national journals and chapters in books. His research interest includes recombinant protein production and purification, enzyme engineering, biomaterials, biodegradation, conversion of hemicellulose to industrial metabolites, protein involved in membrane biogenesis and nanoparticles for industrial applications.