Vol.:(0123456789) 1 3 3 Biotech (2018) 8:445 https://doi.org/10.1007/s13205-018-1470-1 REVIEW ARTICLE Recombinant β-agarases: insights into molecular, biochemical, and physiochemical characteristics Sneeha Veerakumar 1  · Ramesh Pathy Manian 1 Received: 1 June 2018 / Accepted: 3 October 2018 / Published online: 9 October 2018 © Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract Agarases (agarose 4-glycanohydrolase; EC 3.2.1.81) are class of enzymes that belong to glycoside hydrolase (GH) family capable of hydrolyzing agar. Their classifcation depends on hydrolysis pattern and product formation. Among all the agar- ases, β-agarases and the oligosaccharides formed by its action have fascinated quite a lot of industries. Ample of β-agarase genes have been endowed from marine sources such as algae, sea water, and marine sediments, and the expression of these genes into suitable host gives rise to recombinant β-agarases. These recombinant β-agarases have wide range of industrial applications due to its improved catalytic efciency and stability in tough environments with ease of production on large scale. In this review, we have perused diferent types of recombinant β-agarases in consort with their molecular, physi- ochemical, and kinetic properties in detail and the signifcant features of those agarases are spotlighted. From the literature reviewed after 2010, we have found that the recombinant β-agarases belonged to the families GH16, GH39, GH50, GH86, and GH118. Among that, GH39, GH50, and GH86 belonged to clan GH-A, while the GH16 family belonged to clan GH-B. It was observed that GH16 is the largest polyspecifc glycoside hydrolase family with ample number of β-agarases and the families GH50 and GH118 were found to be monospecifc with only β-agarase activity. And, out of 84 non-catalytic carbohydrate-binding modules (CBMs), only CBM6 and CBM13 were professed in β-agarases. We witnessed a larger het- erogeneity in molecular, physiochemical, and catalytic characteristics of the recombinant β-agarases including molecular mass: 32–132 kDa, optimum pH: 4.5–9, optimum temperature 16–60 °C, K M : 0.68–59.8 mg/ml, and V max : 0.781–11,400 U/ mg. Owing to this extensive range of heterogeneity, they have lion’s share in the multibillion dollar enzyme market. This review provides a holistic insight to a few aspects of recombinant β-agarases which can be referred by the upcoming explor- ers to this area. Keywords Recombinant β-agarases · Glycoside hydrolase · Molecular characteristics · Physiochemical properties · Kinetic properties Introduction Agarases (EC 3.2.1.81) are the glycoside hydrolases (GH) that belong to the Carbohydrate Active Enzymes (CAZy) (2018). The glycoside hydrolases of β-agarases catalyzes the breakdown or modifcation of carbohydrates and gly- coconjugates, whereas the carbohydrate-binding domains are non-catalytic modules with carbohydrate-binding activ- ity that are attached to the glycoside hydrolases. These carbohydrate-binding domains facilitate the catalytic action by binding to the substrates, but they do not play crucial in agarolytic activity (Ohta et al. 2004). A few glycoside hydrolases those contain catalytic domains of diferent GH families are multifunctional enzymes. Depending upon the product profle and specifcity to its substrate (Temuujin et al. 2012), agarases can be classifed into endotype agar- ase and exotype agarase where they yield neoagarotetraose and neoagarobiose as their end products, respectively (Liang et al. 2014). Agarases perform a vital role in the breakdown of agar into simple sugars. Agar is considered to be one of the imperative hydrophilic polysaccharides that resides in the cell wall of red sea weeds which possess the gelling property. Agar is primarily composed of agarose and aga- ropectin (Fu et al. 2009). Almost 70% of agar is comprised * Ramesh Pathy Manian mrameshpathy@vit.ac.in 1 Department of Biotechnology, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore 632014, India