Pectinase

Pectinases, also known as pectic enzymes, are produced in plants which degrades the polysaccharide pectin. They are hydrolytic enzymes involved in the metabolism of cell wall, growth of cell, senescence and abscission.

Structure of pectinase with functional groups

Pectinases are polygalacturonases that hydrolyse α-1,4-glycosidic bonds to produce pectate, methanol and pectate lyases and finally forming galacturonides. Main microbial producers of pectinases are Bacillus, Aspergillus, Saccharomyces, Erwinia, Kluyveromyces, Aspergillus, Rhizopus, Trichoderma spp. etc and main applications includes vegetables processing, scouring of cotton, vegetable oil extraction, wastewater treatment, probiotics, bleaching of paper and fermentation of tea, coffee and alcoholic beverages.

Production of Pectinases


Main substrates used includes soil, agricultural waste, organic waste, plant extracts and factors influencing optimum enzyme production includes temperature pH, nitrogen source, carbon source, fermentation time and presence of trace elements. Commercial production of pectinases involves methods such as solid-state fermentation, submerged fermentation and liquid fermentation.

Solid State Fermentation is one of the preferred methods due to less energy requirements, easy availability of substrates, higher enzyme production and lower effluent generation. Substrates for this type of fermentation includes wheat bran, wheat straw and citrus wastes.

Pectinase produced from microbial sources, particularly Bacillus subtilis, is found to be stable over wide range of pH and temperature conditions. With the right mix of substrates, enzyme production was found to increase and the pectinolytic activity was also found to be at an optimum level. Commonly used Bacillus strains for pectin production includes Bacillus subtilis, Bacillus pumilis, Bacillus licheniformis, Bacillus coagulans, Bacillus endophyticus and many more.

A special attribute of pectinases produced by Bacillus spp. is thermostability. This is predicted to be because of the cysteine residues present in the amino acid sequences which enables the formation of disulphide bridges and gives a strong hydrophobicity to pectinase.

Applications

Prebiotics: Pectin and pectin-derived oligosaccharides are emerging as excellent candidates in new generation prebiotics. It has been observed that intestinal bacteria ferment methylated pectin to form short-chain fatty acids (SCFA) such as acetate, propionate, and butyrate, which are beneficial to health. Pectinase is used to make functional food components, nutraceuticals and boost food’s antioxidant potential.


Wastewater Treatment: Municipal and agricultural waste may have a considerable amount of pectic substances. This may disrupt various treatment processes such as dewatering, spray irrigation, direct activated sludge treatment and chemical hydrolysis and methane fermentation. Addition of pectinase degrades pectinaceous substances and sides the process of activated sludge treatment.

Paper bleaching, deinking and recycling: A combination of pectinase and xylanase enzyme is being used as bio-bleaching agent to brighten the paper and improve its physical properties. This approach provides an eco-friendly and a much efficient alternative against chemical pectinases as it increases the amount of chlorine released in the environment. Biological deinking and bleaching would aid in lowering the BOD and COD of waste water before disposal.

Recycling of Waste Paper: Enzymatic deinking minimizes pollution risks, energy consumption and disposal problems. During the deinking process, a group of enzymes - pectinases, hemicellulases, cellulases, and ligninolytic enzymes are used. Enzymes alter the bonding properties of ink and fibre, resulting in the removal of ink from the surface of the fibres during washing.

Clarifying fruit juices: Crushing of fruits produces viscous fruit juice and gelatinous precipitates. These precipitates make obtaining clear fruit juices a difficult process. Pectinases degrades these gel-like substances and while doing so, releases phenolic substances which serve as antioxidants.


Oil Extraction: Pectinase treatment yields oil of superior quality than organically extracted oil with lower fatty acids, peroxide value and colour intensity. Retaining of phospholipids in solid phase reduces the cost for refining process. Pectinase is used in the extraction of essential oils from various sources such as olives, flaxseed oil, dates, etc.

References

  1. Bijesh Kavuthodi and Denoj Sebastian, Biotechnological valorisation of pineapple stem for pectinase production by Bacillus subtilis BKDS1: Media formulation and statistical optimization for submerged fermentation, Biocatalysis and Agricultural Biotechnology, https://doi.org/10.1016/j.bcab.2018.05.003

  2. Kaur, S.J., Gupta, V.K. Production of pectinolytic enzymes pectinase and pectin lyase by Bacillus subtilis SAV-21 in solid state fermentation. Ann Microbiol 67, 333–342 (2017). https://doi.org/10.1007/s13213-017-1264-4

  3. Prajapati J, Dudhagara P, Patel K. Production of thermal and acid-stable pectinase from Bacillus subtilis strain BK-3: Optimization, characterization, and application for fruit juice clarification. Biocatalysis and Agricultural Biotechnology. 2021 Aug 1;35:102063.

  4. Rebello, S., Anju, M., Aneesh, E.M. et al. Recent advancements in the production and application of microbial pectinases: an overview. Rev Environ Sci Biotechnol 16, 381–394 (2017). https://doi.org/10.1007/s11157-017-9437-y

  5. Chen, Y., Liu, Y., Qiu, J. et al. Co-expression of protease and pectinase in Bacillus subtilis using the herbal saponin extract as substrate. Int Microbiol 21, 223–229 (2018). https://doi.org/10.1007/s10123-018-0019-9

  6. Setegn Haile, Abate Ayele, "Pectinase from Microorganisms and Its Industrial Applications", The Scientific World Journal, vol. 2022, Article ID 1881305, 15 pages, 2022. https://doi.org/10.1155/2022/1881305