Continuous ethanol removal from fermentation broths

Ethanol selective forward osmosis membrane

Why is forward osmosis a good enabling technology for unlocking productivity gains from more efficient industrial processes?

Membrane filtration is a process where substances are physically retained on a filter surface with small pore sizes. In industrial processes membrane filtration is used to isolate, refine & concentrate product streams at various production stages:

  • Extraction of whey from milk.
  • Removal of lactose from milk.
  • Removal of colorants from milk.
  • Concentration of juices and beverages into concentrates.
  • Clarification, fractionation, desalting and purification of different beverages.

In industrial processes forward osmosis membrane technologies enjoy at least three key advantages over traditional pressure driven membrane technologies:

  1. Gentle water removal without application of hydraulic pressure and high temperature protects fragile components from undesired degradation and results in higher quality end products.
  2. High performance resilience and operational stability, which reduces the frequency and intensity of cleaning cycles.
  3. Ability to achieve higher concentration factors.

What is special about the forward osmosis technology from SideStroem Water Technologies?

SideStroem Water Technologies recognizes the need for more efficient industrial processes to reduce the overall ecological impact of industrial production.

One high-impact source of productivity gains is to continuously remove any ethanol that is produced as a byproduct in fermentation liquids. Fermentation is a microbial process by which microorganisms convert carbohydrates into desirable metabolic end products. Fermentation industries are increasingly utilizing specially engineered microorganisms to meet an increasing demand for hard to come by natural ingredients such as resveratrol, stevia, vanillin, and even safron. The removal of ethanol serves to avoid ethanol’s inhibitory effect on microbial growth, which already kicks in at ethanol concentrations below 2% (20g/l). This will ultimately enable fermentation processes to run continuously as compared to today’s batch processes.

SideStroem is therefore developing a novel nanofiltration-type forward osmosis (NF-FO) technology tailored to selectively remove ethanol from fermentation broths. The schematic below illustrates the overall process of ethanol removal.

Continuous removal of ethanol from fermentation broths

Our development strategy

We will utilize similar chemistry known from today’s nanofiltration (NF) membrane technologies to achieve a forward osmosis membrane with high rejection for divalent salts (e.g. MgSO4) and low rejection for ethanol.

The end result is a nanofiltration-type forward osmosis (NF-FO) membrane capable of continuously removing ethanol from fermentation broths.

Furthermore, SideStroem’s NF-FO membrane will enjoy a higher water flux and less concentration polarization in comparison to today’s water selective forward osmosis membrane technologies.

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