In the early days, the quality of crude glycerin produced at biodiesel plants was of little concern to biodiesel producers. \u201cU.S. biodiesel producers were mainly interested only in the fuel aspect of the business and paid little attention to the byproducts they produced, even though crude glycerin production is 10 percent of the final product,\u201d says Darol Brown, president of Portland, Ore.-based Sego International Inc. \u201cMost did not pay attention to whether they could find a market for the glycerin, or what level of purity the market required. It was generally considered that a market for the crude would develop without their involvement, so they put no time or effort into understanding the total end result of the process.\u201d Brown says in the 1990s, he was the largest importer of refined glycerin in the U.S. \u201cWhat they needed to consider, and what they have now learned, is that the price they get for their byproducts helps offset their cost of production and profits,\u201d he says. \u201cThose who did not understand this have generally been bought out, or they have gone out of business.\u201d<\/p>\n
One example of algae research to produce glycerin is from a\u00a0\u00a0doctoral student \u00a0– Karthikeyan Gopalakrishnan\u00a0at the biosystems engineering department at Clemson University. Gopalakrishnan has been researching the use of crude glycerin as a carbon substrate to increase biomass and lipid production in the algae strain Chlorella protothecoides. \u201cGlycerin is a three-carbon sugar alcohol that can be consumed by algae as a carbon source to produce oils,\u201d he says. \u201cThe algae I grow in the lab produce about 60 percent oleic acid, which is an Omega-9 fatty acid.\u201d<\/p>\n
Gopalakrishnan says in autotrophy mode, carbon dioxide is a carbon source when coupled with sunlight or artificial light, and oxygen is produced in the process. \u201cIn the heterotrophy mode, organic carbon sources like glycerol and glucose can be used,\u201d he says. \u201cThe presence of glycerin accelerates the growth of this algal species when compared to carbon dioxide alone.\u201d In addition to crude glycerin, Gopalakrishnan provides other nutrients like yeast extract (a nitrogen source), some phosphate salts (a phosphorous source), vitamins and micronutrients. He says 1 gram of glycerol yields about 0.5 grams of algae containing 50 to 60 percent lipids.<\/p>\n
\u201cFrom my research, methanol has proven to decelerate the growth of the microalgae Chlorella protothecoides,\u201d Gopalakrishnan says. \u201cOther researchers have proved that Chlorella protothecoides has high salt tolerance, as high as 35 grams per liter, which can be equivalent to sea water.\u201d<\/p>\n
The goal of his research has been to increase biomass and lipid productivities, an important requisite for commercialization, and to do that, Gopalakrishnan built on previous research on the effect of the carbon\/nitrogen ratio, which is \u201cvery important for lipid accumulation,\u201d he says. \u201cThis was identified [by Yen-Hui Chen and Terry H. Walker at Clemson University] and I have used that in my research for improved biomass and lipid productivities.\u201d<\/p>\n
Gopalakrishnan has yet to work with commercial partners on his research, but says, \u201cI would love to work with someone, to see my research into commercial production. Algae is the future of our lives, and I do envision algae biodiesel a reality in the future.\u201d For this to happen, he says, focus must be put on furthering research and receiving government help in the form of grants.<\/p>\n