SBIR-STTR Award

We have developed an enzyme process to produce GOS from whey lactose. GOS is a prebiotic with wide applications in human and animal foods. However, glucose and galactose are also produced in the process and must be removed from GOS because these monosaccharides do not have and can reduce the prebiotic effect. Xanthan gum is a microbial polysaccharide widely used as a suspending, stabilizing, and thickening agent in food and oil-recovery industries. This project is to develop a novel integrated fermentation-ultrafiltration process for economical production of xanthan gum from glucose and galactose present in the waste sugar stream from the GOS production process. Converting the unwanted waste sugars to high-value GOS and xanthan gum can reduce the waste from and improve the economics of whey processing, thus benefiting the dairy industry by turning the low value whey lactose ($0.2/lb or less) into highly profitable products. OBJECTIVES: The goal of this project is to develop an integrated fermentation-ultrafiltration process for economical production of xanthan gum from glucose and galactose present in a waste sugar stream from a galacto-oligosaccharides (GOS) production process. Converting the unwanted waste sugars to high-value GOS and xanthan gum products not only can reduce the waste from but also can improve the economics of whey processing. The new process can reduce the production cost for xanthan gum by more than 50% due to increased productivity and final product concentration. Both GOS and xanthan gum are high-value products (~$5/lb) with large market sizes (more than 25,000 ton for GOS and 75,000 for xanthan gum). The new process should benefit the dairy industry by turning the low value whey lactose ($0.2/lb or less) into highly profitable products. APPROACH: We will develop a novel, rotating fibrous bed bioreactor (RFBB) for cell immobilization and fermentation to produce cell-free xanthan gum broth that can be readily concentrated and purified by ultrafiltration. The RFBB can overcome mixing and aeration problems commonly associated with viscous fermentation when carried out in conventional stirred tank bioreactors. The RFBB can double the reactor productivity and reach a high xanthan gum concentration of more than 70 g/L (vs. less than 30 g/L). The effects of process conditions on the final xanthan gum properties (viscosity, molecular weight, etc.) will be studied to evaluate the feasibility of producing xanthan gum from glucose and galactose

There are ~80 billion lbs of cheese whey generated annually in the dairy industry and much of this byproduct has no economical use at the present time and requires costly disposal because of its high biological oxygen demand. Converting the unwanted waste sugars to high-value GOS and xanthan gum products not only can reduce the waste from but also can improve the economics of whey processing. The integrated RFBB fermentation-ultrafiltration process can reduce the production cost for xanthan gum by more than 50% due to the increased productivity and final product concentration. Both GOS and xanthan gum are high-value products (~$10/kg) with large market sizes (more than 25,000 tons for GOS and 75,000 tons for xanthan gum). The new process should benefit the dairy industry by turning the low-value whey lactose (<$0.5/lb) into highly profitable products. OBJECTIVES: The goal of this project is to develop an integrated fermentation-ultrafiltration process for economical production of xanthan gum from glucose and galactose present in a waste sugar stream from a galacto-oligosaccharides (GOS) production process. There are ~80 billion lbs of cheese whey generated annually in the dairy industry and much of this byproduct has no economical use at the present time and requires costly disposal because of its high biological oxygen demand. The specific objectives and tasks for Phase II include: 1) optimize cell immobilization on cotton cloth in the RFBB; 2) optimize and scale up the RFBB in oxygen transfer and xanthan gum fermentation; 3) optimize and scale up ultrafiltration of xanthan gum broth; 4) test and scale up the integrated RFBB fermentation and ultrafiltration process; 5) produce xanthan gum product samples for further product development and testing; and 6) evaluate economic feasibility. APPROACH: We have developed an immobilized enzyme process to produce GOS from whey lactose. GOS is a prebiotic with wide applications in human and animal foods. However, glucose and galactose are also produced in the process and must be removed from GOS because these monosaccharides do not have and can reduce the prebiotic effect. Xanthan gum is a microbial polysaccharide widely used as a suspending, stabilizing, and thickening agent in food and oil-recovery industries. In this project, we will develop a novel, rotating fibrous bed bioreactor (RFBB) for cell immobilization and fermentation to produce cell-free xanthan gum broth that can be readily concentrated and purified by ultrafiltration. The RFBB can overcome mixing and aeration problems commonly associated with viscous fermentation when carried out in conventional stirred tank bioreactors. The RFBB can double the reactor productivity and reach a high xanthan gum concentration of more than 70 g/L (vs. less than 30 g/L). The effects of process conditions on the final xanthan gum properties (viscosity, molecular weight, etc.) will be studied to evaluate the feasibility of producing xanthan gum from glucose and galactose.