Bois d’Arc Bioproducts explores the commercialization of Osage orange fruit as a source of biofuel feedstocks and animal feed. The company’s goal is to create silvopastures of Osage orange trees, collect the fruit and extract the marketable biofuel feedstocks.
Why should the Osage orange, be considering an alternative nonfood feedstock for Bioenergy?
The Osage Orange fruit has three potential non-food feedstocks: vegetable oil, sugars/carbohydrates and phytochemicals.
Seeds are 11% of the weight of the fruit and are composed of 5.9% water, 6.7% ash, 20.8% carbohydrate, 33.9 % protein, and 32% fat (Soloua et al., 2009). Researchers at the USDA, Bio-Oils Research Unit (Moser et al, 2011) were able to prepare biodiesel from the oil extracted from Osage orange seeds.
A fruit tree will yield 450 kg of fruit/tree which equates to 49.2 kg of seeds and 16.2 kg of vegetable oil per tree. Assuming 100 producing female trees per hectare, one hectare would produce 1620 kg/ha or 1800 liters/ha. The fruit has been reported to contain 15% sugars and 7% other carbohydrates on a dry weight basis (Clopton and Roberts, 1949).
If planted at a density of 100 trees/ha (10 meter centers), 1,073 liters/ha (115 gallons/ac) of ethanol could be produced annually (Seibert et al, 1986). In other studies, the fresh fruit could have as much as 46% pectin in its solids (Aliev, 1961). If the complex carbohydrate is indeed pectin, Saccharomyces cervisiae will not convert the galacturonic acid subunit to ethanol (van Leeuwenhoek, 2006). Certain anaerobic bacteria and yeast can convert galacturonic acid to ethanol by using anaerobic bacteria and yeasts (Edwards and Doran-Peterson, 2012). Very little has been discussed in the technical literature about the high levels of flavones and other phytochemicals present in the fruit as a potential renewable energy sources.
Bois d’Arc Bioproducts also provides agroforestry services such as silvopastures (growing trees in pastures), alley cropping (rows of trees grown within rows of crops), wind breaks (trees grown to protect crops from hot and dry winds) and riparian buffers (trees grown along streams to reduce errosion and nutrient leaching). Most of the tree plantings will be financed by selling carbon offset credits for trees planted to sequester carbon and remove green house gases such as nitrous oxides and air polutants such as ozone, sulfur dixode and small particulates.