US researchers turn waste bread into added-value

US researchers have developed a bioprocess that converts glucose from bread waste into value-added products, such as ascorbic acid (vitamin c). 

Working within the USDA’s Agricultural Research Service (ARS) Centre, the team has found a way to use Pseudomonas reptilivora bacteria, ensuring the adage “one man’s trash is another man’s treasure” remains true. 

It is estimated that 12.5 million tons of bread – including rolls, croissants and other baked goods – go uneaten worldwide each year. While a portion of this bread waste provides livestock with a source of carbohydrate and protein, the remainder can pose a disposal problem. 

Now, team members have devised fermentation procedures that encourage the bacteria to consume the glucose in bread waste and convert it into 2-keto-D-gluconic acid (2KGA). 

According to research chemist and team member Badal Saha, 2KGA is a so-called ‘platform chemical’ that helps synthesise bulk quantities of ascorbic acid and other substances with wide-ranging food and industrial applications.

It can also be used as a detergent builder, cement plasticiser and precursor chemical for herbicide compounds.

The team’s findings – reported in Biomass Conversion and Biorefinery in March 2020 – form part of the ARS’ overarching aim to develop new, value-added uses for agricultural commodities, especially if they can ease the reliance on raw materials made from fossil fuels.