Pectin classifications, mode of action and factors influencing pectinase production

Pectin is known as a polymer of galaturonic acid. Pectins are commonly found in plants due to the presence of cell walls; with the pectins categorised into different classes, owing to the differences of their solubility in water, percent methyl group and carboxyl group esterification of the galacturonate units. Pectinases (pectin enzymes) are biocatalysts that split pectin into simpler forms. Over the years, the production of this enzyme has been discovered from inexpensive agro wastes and environmental microorganisms which have been evaluated for their specific capacities to effectively generate this enzyme. The production of pectinase via fermentation is made possible using the substrate, pectin, an inducer. Fermentation is the primary mode for pectinase production; as microorganisms employed in the fermentation process act by degrading the more complex substrate into simpler forms with the production of energy. Solid-state and submerged fermentations are the main fermentation methods employed in the industrial production of pectinases. The existence of the different types of pectin is indicative of the corresponding pectinases produced, and the justification for the mode of action during catalysis. Several factors have been implicated in pectinase production, such as the type of fermentation method used (solid-state fermentation or submerged fermentation), others are; the substrate type employed in fermentation, pH, temperature, duration of fermentation, substrate composition, type of metal ion, extraction solvent used, and the type of precipitation method used for concentrating the enzyme. This review gives an overview of pectin and processes leading to the production of the enzyme and simplifies some major modes of action involved in the application of these enzymes and some relevant factors for optimum production and application of the enzyme. The review also shows advances in the extraction of pectin. Some challenges and next steps for future research have also been pointed out.