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Archives (2003) : Tobacco

Paper making from tobacco stalks by Likha Cuevas

January-March 2003 Volume 5 No. 1

Filipino handicrafts are one of the most unique and marketable goods craved by western buyers. Some are Christmas décor made from handmade paper and paper pulp. Mrs. Irma Yang, an exporter of paper handicrafts, said that paper is a versatile medium.

However, exporters cannot meet the demand for paper-based products due to low supply of cellulose --- the fiber that makes up paper. Cellulose is a major biopolymer and can be found in cotton (94% cellulose) and wood (45-50% cellulose).

To address this demand, Dr. Shirley Agrupis, and her colleagues from the National Tobacco Administration (NTA) are using tobacco stalk as an alternative source of cellulose. Tobacco stalk contains cellulose, lignin, hemicellulose and extractives found in wood. Tobacco stalks are also produced in huge volumes annually as waste.

However, the conventional process of producing cellulose yields harmful chemicals. In pulping, the use of sodium hydroxide or sodium sulfide and other delignifying chemicals produce black effluents, while in bleaching, the use of chlorine-based agents results to chlorinated compounds that forms dioxin. Both waste products are hazardous to the environment.

Environmental and health hazard
According to the World Health Organization, "dioxin is a persistent organic pollutant. Once dioxin enters the environment or the body, they are there to stay due to their uncanny ability to dissolve in fats and to their rock-solid chemical stability." The WHO Fact Sheet reported that short-term exposure to dioxin may result to skin lesions (chloracne and patchy darkening of the skin) and altered liver functions. Long-term exposure may lead to impairment of the immune system, the nervous system, the endocrine system, and reproductive functions. Chronic exposure to dioxin may result to several types of cancer. TCDD (2,3,7,8-tetrachlorodibenzo-para-dioxin), a family of dioxin, was evaluated by the International Agency for Research on Cancer (IARC) in 1997 and was categorized as a, "known human carcinogen."

According to Agrupis, et al., they are searching for a bleaching process that would eliminate this problem without sacrificing the strength of the bleached pulp.

Bio-mechanical pulping process
In this process, pulp is produced with the help of microorganisms without using chemicals. Dried tobacco stalks are soaked in water for 24 hours and then crushed by a compactor. These materials are then chipped (to increase surface area) and treated with fungal strains (Pleurotus ostreatus, Phanerochaete chrysosporium, Trametes versicolor and Coriolus versicolor) and cassava-powder-rice water medium (CPRWM), a fungal nutrient medium. The nutrient medium helps in degrading lignin but still retains the cellulose amount of the pulp. The nutrient medium serves as 'starters' for the fungi before turning to the tobacco material as food source. Tobacco stalk pulp treated with P. ostretus and P. chrysosporium even increased the amount of cellulose content because of the massive hyphaenation on the tobacco stalks. Hyphae, the thread-like branching formation of fungi when growing, are considered cellulosic (made from cellulose) materials.

The fiber length of the fungal treated pulp ranged from 0.5-1.0 mm (which was considered long) while the conventionally treated pulp reduced fiber length (compared with the original pulp). According to the researchers, this indicated the degrading effect of chemicals and shortening of fibers. What's the significance? Fiber length is directly related to mechanical strength of the pulp--the longer the fibers, the stronger they are.

Non- conventional bleaching
Tobacco pulp was bleached using camias, lime, and detergent. The camias juice used was in its pure form while lime and detergent were used at 15% concentration at 10% pulp consistency. In biological bleaching, Trametes versicolor and Phanerochaete chrysosporium were used without additional nutrients.

The pulp treated with fungi gave the highest pulp yield (63-64%), while camias gave the highest bleached yield (51.6%). Next was lime with 49.5% pulp yield and detergent (48.7%). Non-conventional bleaching did not cause cellulose degradation compared to the conventional bleaching (10% CaClO), which gained 39.83%-52.33% pulp.

Non-conventional bleaching agents did not degrade lignin but decolorized the polymer. Detergent was most effective in purifying the tobacco stalk pulp.

The researchers also measured the mechanical strength of the tobacco stalk pulp, the burst index, tear index, folding endurance, and tensile strength. Burst strength refers to the amount of hydrostatic pressure required to rupture a piece of paper while internal tear resistance is the energy required to propagate an initial tear through several sheets of paper at a fixed distance. Tensile strength, pertains to the longitudinal stress a piece of paper can withstand without tearing apart. Stress refers to the force per unit width of a test specimen. Folding endurance is the measure of the number of double folds a piece of paper 15 mm wide can endure before its tensile strength falls below the standard value of 1 kg. Lime-bleached tobacco stalk pulp had the highest mechanical strength.

The scientists recommend the biological bleaching method followed by mild chemical treatment and thorough washing to remove the chromophore compounds which darkens the pulp.

Technology for the countryside
The National Tobacco Administration has been producing tobacco pulp using this technology since 1994. Handmade paper from tobacco stalks has caught the interest of local manufacturers. NTA has invented equipment to meet the growing demand. Today, NTA is the only supplier of tobacco handmade paper.

How can the common Filipino use this technology that requires scientific knowledge? "I believe NTA is always there to assist," Agrupis said.

Agrupis quoted NTA Administrator Carlitos S. Encarnacion, "The goal of this project is to introduce this technology to empower tobacco farmers using their own agricultural wastes. It is our hope that in the future, farmers can sell tobacco stalks for added income or even produce the pulp and paper on their own. That is NTA's dream."

References: Agrupis, SC., Dugay MD., Aganon, W., Pitpit, DL., Fabi, A., and Castro, NU. Non-conventional Agri Waste Utilization: A Cleaner and Greener Process. 2002. tel: (077) 792-2628 or 792-3848;
Bantayan, RB and Razal, RA. Status of Environmental Protection and Control in Philippine Pulp and Paper Mills. Inpaper International: 2001.
Brown, RM Jr. Microbial Cellulose: A New Source for Wood, Paper, Textiles, Food, and Specialty Products.
Chromophore. IUAPAC Compendium of Chemical Terminology. 2nd Ed.1997.
Dioxins and Their Effects on Human Health. WHO Information Fact Sheet No. 225. June 1999.
Tale of Two Ladies in Handicraft Ventures. Global Business Opportunities: Technological Information Promotion System.

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