SMOKING THE STEMS: A STUDY OF PECTIN, LIGNIN AND CELLULOSE

On the subject of Cannabis sativa much has been written over the years, perhaps more than on any other plant. A large focus of this literature is on THC and the dozens of cannabinoids. These compounds by weight are only a tiny percentage of the plant, though economically they are what make up the vast majority of the sales, as medicinal and recreational compounds.

As with almost all plants, most of the weight is in the form of cellulose, which is in the stems and branches. This compound was separated from others, such as lignin and pectin, and was traded for millenia. It did for nearly a century attain the status of being the world’s most traded commodity.

This was mainly due to the emergence of navies that depended on hempen products such as rope and sails. Hemp could readily produce both, as well as fine textiles, which mainly came from the Piedmont region of Italy.

Textile use continued long after metal ships laden with albaca cordage hemp made hemp obsolete as a maritime commodity. Italy, Trieste and North Borneo featured the hemp textile industry on a stamp in the 1950s; presently there are dozens of companies producing attire.

It is worth noting that the cordage, sails and clothing, when worn down, were in turn used to make paper. That trend also gave way as trees were sourced for paper, a change which has caused major deforestation and pollution.

As I have already discussed the use of cannabis-based cellulose for paper in this periodical, I will not enter at large again in this new article but will note to the reader that previous articles by me in the Texas Hemp Reporter discuss cellulose and its use, especially in paper production.

At this point I will introduce two other compounds to the reader: pectin and lignin. The former is best known as the substance in marmalade.

Pectin is a heterosaccharide, found in the cell wall of plants. The term ‘pectin’ includes a number of compounds which vary in the order of the monosaccharides. Under acidic conditions, it forms a gel, most well-known from its use in jellies and jams. In fruit it is a welcome ingredient, which breaks down during maturation to pectinic and pectic acids in the presence of the enzyme pectinose. In general, hard fruits contain more pectin than soft fruits.

In fibrous plants, pectin is removed out of necessity so as to isolate the cellulose, which is the main compound in paper and textiles. Hot-water retting is one way of removing pectin, which is why hot-water retting and boiling have been methods of the hemp farmer. Today hot-water retting is being explored along with enzyme retting. The goal of researchers is the removal of pectin from the stem so as to produce a pure cellulose strand, free from pectin and other substances, such as lignin.

Lignin is a macromolecule characterized by monolignols, the starting material being phenylalinine. It is abundant in trees and herbaceous plants, where it is part of the cell walls, much a part of the xylem. After cellulose it is the most abundant organic compound, accounting for up to 33% of the dry mass of wood. It fills space between cellulose and pectin, giving rigidity, conducting water and defending against pathogens.

Lignin has both a negative and a positive side; it must be removed from plants when processed for paper and textiles, but is in fact on its own a very commercial compound. Studies of its uses began in 1927, when the Marathon Corp. in Rothschild, Wisconsin took an interest in it; since, this firm has been renamed LignoTech USA, and is owned by a Norwegian company, Borregaard.

The commercial uses of lignin and its derivatives include raw materials for use in vanillin, ethanol, humic acid, environmentally friendly dust suppression agents, dispersants in high performance cement applications, textile dyes and agricultural chemicals.