Bio-loading impact study on downstream hydrolysis and fermentation of autoclaved fibre from the Organic Fraction of Municipal Solid Waste (OFMSW)

Summary:

Approximately half of the domestic waste produced in the UK is still not recycled and much is either, burnt to produce energy releasing carbon dioxide into the atmosphere, or placed in landfill with the consequent release of methane; a gas over twenty times more potent than CO₂ in terms of its potential for retaining heat in the atmosphere. Recent research has indicated however that the organic fraction of domestic wastes could potentially become a source of renewable fuels and industrial chemicals. This is commonly dependent on pre-treatments that release low molecular weight feedstocks such as sugars for conversion by yeasts or other microbial fermenters.

Aims:

1. To determine the total available fermentable sugars in repeat-feed batch hydrolysis systems using a municipal solid waste mix pre-treated under a range of different autoclaving parameters.
2. To calculate the theoretical ethanol yield and to conduct fermentation studies to determine actual optimal yields.
3. To assess the economics of the process.

Outcomes:

High levels of sugars were generated from repeat-feed batch hydrolysis systems with minimal inhibitor presence for any of the autoclaving parameters assessed; giving promising theoretical ethanol yields. Repeat two-step hydrolysis and fermentations using antimicrobial additives produced acceptably high ethanol yields in the final product. The economics of the process were assessed with existing schemes and found to be commercially viable.

Impact:

These results are highly impactful and have led to additional work between these partners already, with a large grant application between them currently in progress to move this work further up the TRLs with the intention for commercial viability.

Academic Partner: Jessica Adams, Aberystwyth University

Industrial Partner: Nick Cheffins, Black and Wilson Biorefineries