Lab tries to stretch guayule plant into profit
· By TANNER CLINCH Staff Writer -Eloy Enterprise
· Oct 27, 2016
· ELOY — Guayule, an arid desert bush native to Mexico, is being looked at by many companies that use large amounts of rubber to be a good domestic replacement for Hevea trees, commonly known as rubber trees, which are harvested overseas.
There are many small farms scattered across the state that grow guayule. One of the most prominent places for researching the crop is a small farm in Eloy owned by Bridgestone Tires where workers are studying what makes guayule tick.
There is no doubt that the guayule plant can make rubber. In 2015, Bridgestone came out with its first tire that was made wholly of the plants. During World War II America looked into making rubber domestically with the plant after Japan cut off its rubber supply from Malaysia, but the plan was scrapped after the war ended before it picked up steam.
The problem for many companies is how to make farming the plant profitable, which is one of the main problems that researchers at the Bridgestone lab in Eloy are looking at.
The resins from the plant that one uses for rubber are mostly derived from the bark at the stem of the plant, explained Dr. Dave Dierig, a researcher at the facility. This means that what the company needs to satisfy its rubber needs comes from a small part of the plant.
“If you grew cattle specifically just for the tenderloins, you’d never make any money, right?” said Bill Niura, the project lead at the Bridgestone farm, while he explained there conundrum.
So what do you do with the majority of the biomass that comes from farming the plants? There are a couple ideas the people at Bridgestone had, mostly involving turning it into some sort of fuel.
The leftover biomass, which is roughly 80 percent of the plant, is the wood that comes from the stalk and other plant matter, which comes out looking like small wood pellets after it’s done. If you straight up burn it, it will produce 8,000 British thermal units per pound, said Dierig.
This is almost as efficient as burning a pound of coal, which puts out 9,710 BTU’s per pound according to the U.S. Energy Information Administration. Putting this biomass into coal-fired reactors that use high-sulfur coals could also reduce those sulfur emissions, according to Dierig.
Unfortunately, there really isn’t a market in the U.S. for biomass fuel bricks as there is in much of Europe, according to Niaura.
Another avenue they looked into was turning it into fuel for cars by turning it into ethanol. While other biofuels, such as ones made with corn, get a bad wrap for using food crops to burn in vehicles guayule doesn’t have that problem, it’s produced entirely for industrial uses.
The biomass leftover from the rubber-making process can be turned into an alcohol based fuel via fermentation, according to Niaura. Creating a refinery for it on an industrial scale is a whole different demon.
While the people at Bridgestone figure out what to do with all the plants they harvest for rubber, they are continuing to do research on the plant.
The site in Eloy has been operational for a little over three years, studying the different properties of the plants, how different strains grow, which elevation works best and how harvesting times affect plant productivity.
While humans can make many different kinds of rubber synthetically in a laboratory, natural rubber is still the best for many uses. It is stronger in high-force situations than synthetics due to a property called stress-induced crystallization, according to Niaura.
“Nature makes rubber whether it’s on a tree in the jungle or a guayule in Arizona,” Niaura said.
Moving forward in creating a domestic rubber industry is the goal of Bridgestone. It has other competitors, such as Cooper Tires, and other small companies that make other products, such as Yulex, which makes wetsuits out of the guayule.
Arizona will be a center for the production of guayule just because of its natural climate. The weather is the plant’s natural habitat and the PH balance of the soil in places like the Southeast would not be optimal to grow guayule, according to Niaura.
It make take a while for the company to find a the most productive guayule and make it profitable, it takes roughly two years from planting the seed to harvesting the plant.