Review paper Applications of pectinases in the commercial sector: a review D.R. Kashyap a , P.K. Vohra a , S. Chopra a , R. Tewari b, * a Department of Microbiology, Punjab University, Chandigarh 160014, India b Department of Biotechnology, Punjab University, Chandigarh 160014, India Accepted 10 August 2000 Abstract Pectinases are one of the upcoming enzymes of fruit and textile industries. These enzymes break down complex polysaccharides of plant tissues into simpler molecules like galacturonic acids. The role of acidic pectinases in bringing down the cloudiness and bitterness of fruit juices is well established. Recently, there has been a good number of reports on the application of alkaline pectinases in the textile industry for the retting and degumming of ®ber crops, production of good quality paper, fermentation of coee and tea, oil extractions and treatment of pectic waste water. This review discusses various types of pectinases and their applications in the commercial sector. Ó 2001 Elsevier Science Ltd. All rights reserved. Keywords: Pectinase; Industrial applications 1. Introduction Pectinases were some of the ®rst enzymes to be used in homes. Their commercial application was ®rst ob- served in 1930 for the preparation of wines and fruit juices. Only in the 1960s did the chemical nature of plant tissues become apparent and with this knowledge, sci- entists began to use a greater range of enzymes more eciently. As a result, pectinases are today one of the upcoming enzymes of the commercial sector. Primarily, these enzymes are responsible for the degradation of the long and complex molecules called pectin that occur as structural polysaccharides in the middle lamella and the primary call walls of young plant cells. Pectinases are now an integral part of fruit juice and textile industries as well as having various biotechnological applications. The estimated value of sales of all industrial enzymes in 1995 was $1 billion, of which some $75 million was as- sessed for pectinases. By 2005, the whole world market for industrial enzymes is expected to be $1.7±2 billion (Godfrey and West, 1996). The main emphasis of this article is on the types of pectinases and their applica- tions in industries. 2. Structure of pectin Chemically, pectic substances are complex colloidal acid polysaccharides, with a backbone of galacturonic acid residues linked by a (1±4) linkages. The side chains of the pectin molecule consist of L -rhamnose, arabinose, galactose and xylose. The carboxyl groups of galactu- ronic acid are partially esteri®ed by methyl groups and partially or completely neutralized by sodium, potassi- um or ammonium ions. Based on the type of modi®ca- tions of the backbone chain, pectic substances are classi®ed into protopectin, pectic acid, pectinic acid and pectin (Be Miller, 1986). Protopectin. This is a parent pectic substance and upon restricted hydrolysis yields pectin or pectinic acid. Protopectin is occasionally a term used to describe the water-insoluble pectic substances found in plant tissues and from which soluble pectic substances are produced (Kilara, 1982). Pectic acids. These are the galacturonans that contain negligible amounts of methoxyl groups. Normal or acid salts of pectic acid are called pectates. Pectinic acids. These are the galacturonans with var- ious amounts of methoxyl groups. Pectinates are normal or acid salts of pectinic acids (Kilara, 1982). Pectinic acid alone has the unique property of forming a gel with sugar and acid or, if suitably low in methyl content, with certain other compounds such as calcium salts. Bioresource Technology 77 (2001) 215±227 * Corresponding author. Tel.: +172-541441 ext. 4085; fax: +172- 541409. E-mail address: shaktit@glide.net.in (R. Tewari). 0960-8524/01/$ - see front matter Ó 2001 Elsevier Science Ltd. All rights reserved. PII: S 0 9 6 0 - 8 5 2 4 ( 0 0 ) 0 0 1 1 8 - 8