Lesquerella-based biodiesel adds lubricity in blend

July 14, 2008

BY Ryan C. Christiansen

Web exclusive posted August 7, 2008 at 4:35 p.m. CST

A resilient winter oilseed crop that blooms bright yellow and thrives in the arid soil and brackish waters of the American Southwest might be an ideal feedstock for biodiesel. According to the USDA, the oilseed crop, lesquerella, is especially ideal when that biodiesel is added to low-sulfur and ultra-low-sulfur petroleum diesel fuels.

Lesquerella, a member of the mustard family that grows naturally in Texas, New Mexico, and Arizona, produces seeds that are smaller than alfalfa and oil that is rich in hydroxylated fatty acids, which increase the lubricity of the oil as compared to other vegetable oils. The USDA said the fatty acids contain molecules called estolides, which are rare in other seed oils, and naturally promote the oil to flow more easily under various conditions, including in cold temperatures.

While biodiesel possesses inherently greater lubricity than petroleum diesel and especially low- and ultra-low-sulfur petroleum diesel, biodiesel made from lesquerella oil with hydroxylated fatty acids improves the lubricity of petroleum diesel at lower blends than biodiesel made from other vegetable oils, according to the USDA's Agricultural Research Service.

Lubricity is an important issue, the USDA said, because petroleum diesel that is low in sulfur has led to the failure of engine parts such as fuel injectors and pumps, because they are lubricated by the fuel itself. Essentially, all fuel additives currently available are derived from imported petrochemical feedstocks, which suffer from poor biodegradability and high toxicity, the USDA said.

Eighty-three of the 95 known species of lesquerella grow naturally in North America. A USDA-funded Cooperative State Research, Education, and Extension Service project with researchers in Illinois, Texas, and Arizona, is looking to use lesquerella to produce biodiesel and replace castor oil. The group has collected lesquerella seed from native populations across North America and has developed new breeding lines to increase the oilseed's total oil and hydroxyl fatty acid content, the USDA said.

Lesquerella is a short-duration perennial that is grown in production as an annual. The USDA said Lesquerella fendleri is the most productive of the species that have been evaluated; the species naturally has a seed oil content of 22 percent, however, a germplasm has been developed through breeding that contains 30 percent oil. Lesquerolic acid, a hydroxylated fatty acid, comprises 60 percent of the total oil. The goal is to raise the seed oil content to at least 35 percent.

According to the Arizona Farm Bureau, Lesquerella is planted in October in the southwestern U.S. using a broadcast planter to direct seed. Irrigated using approximately the same amount of water as winter wheat, the majority of the plant's growth occurs between February and March. Seeds develop between March and late May, with harvesting occurring by middle to late June. Approximately 1,500 to 1,800 pounds of seed are produced per acre. The seed hull meal contains 30 percent to 35 percent protein and could be used as a feed supplement for livestock.

The commercialization of lesquerella oil is being led by Technology Crops International, according to the company's Web site.

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