Aquatic biopolymers: understanding theirIndustrial significance and environmental implications

Polymers refer to macromolecules made up of repeating units of smaller molecules covalently bound together to form a bigger molecule. For example, proteins are polymers made up of amino acids, cellulose is made up of repeating units of glucose and polyethylene is made up of repeating units of ethylene. The units which join together to form polymers are referred to as monomers, and the process through which this is achieved is termed polymerization. Biopolymers refer to polymers which are produced by living organisms. The term aquatic biopolymers refers to biopolymers which are produced by living organisms that inhabit the aquatic ecosystem. Since the beginning of the ages, polymers have played a significant role in human life in providing the most basic need, food, in the form of carbohydrates and pro- teins. As life advances, polymers have come to be of great importance to modern civilization, from the food we eat, the portable plastic bottles that give us convenient access to clean drinking water, the medicines we take, basic hygiene, tools and the fuels that run our engines. Polymers are fundamental to our existence as modern humans. Considering that the polynucleotides which form our DNA that carry the instructions for every life function are also polymers, it can therefore be said that polymers indeed make life. The aquatic environment is a rich source of a wide range of natural resources, and among those resources are polymers. They are found in the cell walls, tissues, exoskeletons, secretions and anatomical regions of aquatic organisms across the five kingdoms. A large variation of factors exists in the aquatic environment. These variable factors include salinity, depth, light intensity, temperature, pressure, density, pH, prey/predator presence, nutrients, dissolved gases, water flow rate, flora and fauna. These factors determine the types of biochemicals produced by the different organ- isms to survive their environment, even more so where they are in such direct contact with the continuous medium (Christophe et al. 2015). Such variation in the envi- ronmental factors also translates to a diverse range of polymers. Over the course of evolution of life, living organisms both plants and animals have devised means to produce, absorb, store and process different forms of biopolymers. This ranges from polysaccharides used for energy and structure, proteins for metabolism and cell renewal and polyesters for water repelling among others. These are stored in different anatomical regions of the plant. Carbohydrates, for example, are stored in chloroplasts, cytoplasm, periplastic compartment, peri-plastid membranes, in the cytoplasm, and vacuole localized in the cytoplasm (Prabhu et al. 2019).