Abstract
Carrageenan, one of the phycocolloids is a sulfated galactan made up of linear chains of galactose and 3,6-anhydrogalactose with alternating α-(1 → 3) and β-(1 → 4) linkages and further classified based on the number and the position of sulfated ester(s); κ-, ι- and λ-carrageenan. Enzymes which degrade carrageenans are called k-, ι-, and λ-carrageenases. They all are endohydrolases that cleave the internal β-(1–4) linkages of carrageenans yielding products of the oligo-carrageenans. These enzymes are produced only by bacteria specifically gram negative bacteria. Majority of the marine bacteria produce these enzymes extracellularly and their activity is in wide range of temperature. They have found potential applications in biomedical field, bioethanol production, textile industry, as a detergent additive and for isolation of protoplast of algae etc. A comprehensive information shall be helpful for the effective understanding and application of these enzymes. In this review exhaustive information of bacterial carrageenases reported till date has been done. All the aspects like sources, production conditions, characterization, cloning and- biotechnological applications are summarized.
Highlights
In this review exhaustive information of bacterial carrageenases reported till date has been done
Hydrocolloids can be defined as substances that interact with water to form colloid systems
The carrageenans are extracted from the carrageenophyte red seaweed genera Kappaphycus, Gigartina, Eucheuma, Chondrus, and Hypnea, in which the carrageenans comprise up to 50 % of the dry weight (Knudsen et al 2015). j-Carrageenan is mostly extracted from Kappaphycus alvarezii, known in the trade as Eucheuma cottonii, while i-carrageeman is predominantly produced from Eucheuma denticulatum, known as Eucheuma spinosum. k-Carrageenan is obtained from seaweeds within the Gigartina and Chondrus genera, which as sporophytic plants produce k-carrageenan while they make a j/i-hybrid as gametophytic plants (Van De Velde et al 2001)
Summary
Hydrocolloids can be defined as substances that interact with water to form colloid systems. Carrageenans are commercially important hydrophilic colloids (water soluble gums) which occur as matrix material in numerous species of red seaweeds [comprise up to 50 % dry weight (Rhodophyta)] wherein they serve a structural function analogous to that of cellulose in land plants They are a group of biomolecules composed of linear polysaccharide chains with sulphate half-esters attached to the sugar unit. Improved production (630 Uml-1) of the enzyme carrageenase was obtained by starting bacterial growth on a cheap carbon source (lactose) and adding small amounts of carrageenan (0.15 %) to initiate enzyme production Similar to this Dyrset et al (1997) showed the role of casamino acid (3.5 gl-1) in fed batch fermentation of Pseudomonas carrageenovora NUMB 302 and significantly achieved increase in enzyme activity by 2.6 times (84,000 Uml-1).
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