Production of glycolipid biosurfactants, mannosylerythritol lipids, by a smut fungus, ustilago scitaminea NBRC 32730

Abstract

A smut fungus Ustilago scitaminea NBRC 32730 on sugar cane (Saccharum) was found to accumulate a large amount of glycolipids in the culture medium. As a result of structural characterization, the main glycolipid was identified as MEL-B, 4-O-ß-(2′,3′-di-O-alka(e)noyl- 6′-O-acetyl-D- mannopyranosyl)-erythritol. The MEL-B was sufficiently produced from a variety of sugars such as sucrose, glucose, fructose, and mannose. Olive oil and methyl oleate were also available as carbon sources to produce MEL-B. However, these residual oils made product recovery very complicated. Under optimal conditions, a maximum MEL yield of 12.8 g/l was achieved by feeding of sucrose.