Title: Production of arabitol from glycerol: strain screening and study of factors affecting production yield Authors
|Koganti, Srujana -|
|Kuo, Tsung Min|
|Smith, Nathan -|
|Ju, Lu-Kwang -|
Submitted to: Applied Microbiology and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 15, 2010
Publication Date: December 3, 2010
Citation: Koganti, S., Kuo, T., Kurtzman, C.P., Smith, N., Ju, L. 2011. Production of arabitol from glycerol: Strain screening and study of factors affecting production yield. Applied Microbiology and Biotechnology. 90(1):257-267. Interpretive Summary: This research identified several strains of yeast that could produce sugar alcohols, such as arabitol and xylitol, from glycerol. Glycerol is a major by-product from the chemical conversion of vegetable oils to biodiesel fuel. A significant factor in the economy of biodiesel production is finding a valuable use for the resulting glycerol. Of 214 yeasts tested, several strains produced significant quantities of arabitol. One of these higher producing yeasts, Debaryomyces hansenii SBP-1, gave sufficient yields of arabitol to merit further development for economical utilization of waste glycerol. Sugar alcohols have application in a number of food and health care products, and therefore these results are important to the food, health care, and biofuel industries.
Technical Abstract: Glycerol is a major byproduct from biodiesel production, and developing new uses for glycerol is imperative to overall economics and sustainability of the biodiesel industry. With the aim of producing xylitol and/or arabitol as the value-added products from glycerol, 214 yeast strains, many osmotolerant, were first screened in this study. No strains were found to produce large amounts of xylitol as the dominant metabolite. Some produced polyol mixtures that might present difficulties to downstream separation and purification. Several Debaryomyces hansenii strains produced arabitol as the predominant metabolite with high yields, and D. hansenii strain SBP-1 was chosen for further study on the effects of several growth conditions. The optimal temperature was found to be 30 degrees C. Low dissolved oxygen concentrations or anaerobic conditions inhibited polyol yields. Arabitol yield improved with increasing initial glycerol concentrations, reaching approximately 50% (w/w) with 150 g/L initial glycerol. However, the osmotic stress created by high salt concentrations (greater than/or equal to 50 g/L) negatively affected arabitol production. Addition of glucose and xylose improved arabitol production while addition of sorbitol reduced production. Results from this work show that arabitol is a promising value-added product from glycerol using D. hansenii SBP-1 as the producing strain.