Enhancement of Bioprocess Product Yields

Method of Increasing the Efficiency of the Conversion of Sugars and Other Substrates to Products of Microbial Cultivations

At a Glance

To increase conversion efficiency of metabolic products cultivated from microorgansims, researchers at Colorado State University developed two approaches: (1) cell immobilization and (2) the addition of growth-inhibitory compounds. The combination of the two approaches resulted in an ethanol yield of 0.49 g ethanol/g sugar, 20% higher than previously reported values for free‑cell fermentation of algal hydrolysate. Similar results can be expected for other yeast species grown on other biomass hydrolysates or carbon sources in anaerobic fermentation.


Ethanol and other metabolic products derived from the cultivation of microorganisms form the backbone of industrial biotechnology. With increased interest in sustainability and the move to find replacements for petroleum-derived chemicals, the production of bio-based chemicals is expected to increase substantially over the coming decade. One factor limiting the environmental and economic sustainability of these bioprocesses is the production of cellular biomass by the microorganisms, which de facto reduces the conversion of carbon from the feed (substrate) molecules, typical sugars, to the desired product.


  • Improved economic and environmental sustainability metrics
  • Ethanol production results are significant, as increases of only a few percentage points represent substantial value to the ethanol industry and enhance the life‑cycle assessment of any ethanol fermentation
  • Results demonstrated increased ethanol yield not only for batch cultivation but also for continuous cultivations


  • Biotechnology
  • Ethanol fermentation
Last Updated: November 2019
Vial in a beaker filled with green liquid

Available for Licensing

IP Status

US Patent Pending


Kenneth Reardon
Xingfeng Huang

Reference Number
Licensing Manager

Steve Foster