Is there an alternative to fossil fuels in the production of surfactants? The French-Belgian research team ValBran researched the possibility of making surfactants with high added value from bran. At one stroke, the project has put the potential of this waste product from wheat grain in the spotlight.

Surfactants

Surfactants are agents that change the surface tension between two surfaces. They are also known as surface-active agents. Surfactants are used in a huge range of products and applications, such as detergents, emulsifiers, solvents, foaming agents, agents for reducing surface tension, dispersal agents, etc. 

Non-biobased (petrochemical) surfactants and partially biobased surfactants (consisting of over 40% biologically derived compounds) currently make up the bulk of the market.

The ValBran project therefore focused on fully biobased surfactants (consisting of over 95% compounds derived from biomass). The development and sale of these biosurfactants are constrained by higher costs and other factors. The ValBran project aimed to develop solutions that will remove these barriers to the production of biosurfactants.

Wheat bran as a source for sustainable biosurfactants

The ValBran project focused on the valorisation of wheat bran into surfactants for applications with high added value. There is no shortage of wheat bran in the regions that took part in this project. Mills and companies supplying bio-ethanol have an abundance of this waste product.

The target markets are:

  • cosmetics
  • phytosanitary products
  • additives for food and animal feed
  • detergents

What makes biosurfactants so interesting?

  • their low ecotoxicity and their biodegradability
  • they easily meet regulations
  • they make use of cheap raw materials
  • their great diversity of potential structures
  • they have better foaming properties
  • their wider field of application in comparison to petroleum-based surfactants
  • their antimicrobial properties

This project studied two categories of surfactants:

  • Alkyl polyglycosides (APG): the global market for APGs is estimated at 100,000 tonnes per year. Alkyl polyglycosides are used as emulsifiers in applications such as cosmetics, detergents and phytosanitary products.
  • Sucrose esters: the global market for sucrose esters is approximately 10,000 tonnes per year. Sucrose esters are mainly used as emulsifiers in cosmetics and foodstuffs.

These surfactants are synthesised by hydrolysing cellulose and hemicellulose from wheat bran and grafting an alcohol chain or lipid chain onto these sugars with the help of an enzyme. The next step is to test the surfactant properties of the synthesised molecules.

ValBran results

The evaluation of the properties of the biosurfactants in the project has demonstrated their importance for a range of applications. This importance was confirmed by tests carried out by various companies (ARD in France, Sopura and Nuscience in Belgium) in a range of formulations. Therefore, there is certainly potential for the use of wheat bran for the production of surfactants.

Some of the major conclusions:

  • There is enough wheat bran available for further valorisation.
  • Thanks to the enzymatic technology, biosurfactants with interesting properties can be produced from wheat bran.
  • At present, the production costs are the major obstacle to market growth in biosurfactants, as they continue to be more expensive than their petroleum-based counterparts.
  • The remaining wheat bran from the process could be interesting as animal feed. The effects of the enzymes used for the process (cellulase and hemicellulase) could make the bran easier to digest. Moreover, the fibre content, which is slightly increased in the remaining wheat bran, would be favourable for ruminant feed. These possibilities for valorising bran residue will need further research beyond the project.
  • The experiments as part of the ValBran project were carried out at lab-scale. In order to demonstrate the technical and economic feasibility of the processes, tests must be carried out at pilot-scale. Such a scale-up is a precondition for validating a technology before it moves to the industrial phase.

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