Emerging trends on the role of recombinant pectinolytic enzymes in industries- an overview

The primary energy requirement of almost all life-forms on earth is derived from plant sources. The plant cell wall (PCW) has a chemically complex structure composed of glycoproteins, aromatic compounds and carbohydrates. The carbohydrates include cellulose, hemicellulose and pectin. Cellulose has homogeneous structure, whereas hemicellulose and pectin are heterogeneous. Pectin constitutes as the most complex polysaccharide and is abundantly found in the middle lamella and primary cell wall of PCW. It is also proportionally the highest constituent of plant dry matter. The pectic substances are hydrolyzed by pectinolytic enzymes which are widely present in bacteria, fungi and plants. Pectinolytic enzymes are classified as de-polymerising and de-esterifying enzymes. The de-esterifying enzymes are the accessory enzymes which remove the side chains. The pre-action of de-esterifying enzymes removes the steric hindrance and provides better access to other de-polymerizing enzymes for complete degradation of pectin. This review describes the pectin structure and the structure, function and biochemical properties of recombinant pectinolytic enzymes from different microbial sources. The focus is on the specific role of individual pectinolytic enzymes in various industrial applications such as juice extraction, vegetable puree production, fibre retting, waste water treatment, pharmaceuticals, biomass hydrolysis and production of other value-added products. Thus, the enhanced use of pectinolytic enzymes in these growing industries holds a great potential for gaining insights about their efficient role in various sectors.