Production of ferulic acid from wheat bran

This project aimed to develop a scalable and efficient process to produce ferulic acid from wheat bran.

A phenolic acid, ferulic acid has many industrial applications, including a precursor for the synthesis of natural biovanillin through fermentation, and an active agent in sun creams and anti-ageing skin care products, due to its high antioxidant activity and UV absorbing capacity. It also has several potential applications in the flavour/aroma, pharmaceutical and chemical industries, as a precursor for the synthesis of various aromatic molecules, through processes based on synthetic chemistry or microbial and enzyme transformations.

Ferulic acid is currently produced commercially from rice bran pitch, the waste stream generated during the production of rice bran oil. Due to the increased commercial applications of ferulic acid, the milling industry is interested in obtaining ferulic acid from alternative sustainable sources. The fact that wheat bran contains high amounts of ferulic acid (5–15 g/kg), which can potentially be obtained from a simpler fractionation process compared to corn bran, makes this abundant material a potentially good source of ferulic acid.

This project addressed limited knowledge on:

1. The ferulic acid content of various wheat cultivars from various locations in the UK.
2. The effect of mechanical processing of wheat grains, such as conventional milling and debranning (pearling) on the ferulic acid content of wheat bran.
3. The development of a scalable bioconversion process, based on the enzymatic deconstruction of wheat bran using a mixture of hydrolases, capable of releasing the ferulic acid linked to the arabinoxylans of wheat bran.
4. The cost and scalability of such a process.

We determined the ferulic acid contents in various bran fractions from two commercial wheat mills that do not currently use these bran fractions as a source of ferulic acid or of other high value products.

We showed that the yield of ferulic acid is particle-size dependent and it is possible to increase the yield by reducing the particle size of the starting material.

We compared the phenolic acid content to the rate of debranning and showed that the outer 5% of the wheat grain has the highest content of ferulic acid. There is significant potential to increase the ferulic acid yield, if the particle size of the highest yielding bran fraction is reduced, which may have implications for the cost-benefit analysis of ferulic acid extraction from waste bran fractions from wheat.

An optimised process for the enzymatic deconstruction of wheat bran was developed and a ferulic acid production equal to that obtained by chemical methods was achieved.

This research demonstrated that the development of a sustainable process to produce natural ferulic acid from wheat bran has significant potential.

The purity of the ferulic acid produced was significantly improved through scalable and cost-effective approaches, although further research will be needed to ensure complete removal of impurities.