University of Bath

Developing an alternative to palm oil from waste resources, using yeast

We're using energy-efficient microwaves and unique fermentation processes to develop a palm oil substitute from lignocellulosic waste.

Petri dish with stripes of yeast culture
We're researching the biology of yeast to create an alternative to palm oil

Palm oil is widely used in food, cosmetics, personal care and bio-energy industries. However, the production of this plant-derived oil has led to mass deforestation, loss of biodiversity and the destruction of habitats critical for rare and endangered species. We're investigating sustainable ways to produce an alternative that could help reduce the environmental and social impacts of palm oil production.

Our project aims to develop a pilot-scale, multi-product biorefinery. Coupling breakthroughs in low-energy biomass treatment with unique fermentation, we'll produce a microbial oil and other marketable high-value products.

The oil we produce from the yeast Metschnikowia pulcherrima is a suitable palm oil substitute. The feedstock for this process is obtained through an innovative one-step microwave process which depolymerises (breaks down) waste lignocellulosic material (plants biomass) that is used by the yeast. Using waste removes the need for agricultural land to cultivate material, and thus helps to reduce any impact from food crop displacement.

Our research will:

  • use microwave technology as a scaled continuous route to depolymerising lignocellulosic feedstocks. This is done without acidic or enzymatic hydrolysis
  • demonstrate pilot-scale fermentation and continuous processing of a robust, oleaginous (oil producing) yeast strain. This is carried out under a range of feedstock conditions to produce a microbial oil and other high-value compounds
  • enhance Metschnikowia pulcherrima as an industrially functional yeast. This will be achieved through strain screening for desirable traits, adaptive laboratory evolution and genetic improvement
  • design an environmentally and economically sustainable, multi-product biorefinery system

Optimising microwave processing at pilot scale

We are evaluating a range of sustainably sourced waste feedstocks (crop residues and other organic/carbon-containing industrial by-products or wastes). Some compounds produced during the process of depolymerising lignocellulose can limit yeast biomass growth and affect the efficiency of the overall process. We will assess feedstocks for depolymerisation efficiency and production of inhibitory compounds after microwave processing.

Low-temperature microwave processing of lignocellulosic material is an effective method for obtaining:

  • fuels (bio-char, bio-oil)
  • chemicals (sugars, anhydrosugars, phenols)
  • materials (mesoporous lignin)

The one-step microwave process is more efficient than multi-step acid hydrolysis or enzymatic processing, which can have high economic and environmental costs. We are building on this technique and developing a scalable method for obtaining material suitable as microbial biorefinery feedstocks.

This research phase is being carried out in the Green Chemistry Centre of Excellence at the University of York.

Fermentation and continuous extraction at pilot scale

We are exploring ways to optimise yeast fermentation. Additionally, we're developing a continual extraction process and a method for downstream processing of our multi-product system.

Metschnikowia pulcherrima can grow on many waste feedstocks, including wheat straw, rapeseed meal and other carbon-containing industrial wastes. We're carrying out fermentation and processing to extract the oil and other marketable products, in Bath's laboratories, before scaling up to pilot level (30,000L) at our industrial partner site.

This research is taking place in the Department of Chemical Engineering at Bath.

Improving Metschnikowia pulcherrima as an industrial yeast

We are researching the biology of Metschnikowia pulcherrima to advance its development as an industrially functional yeast. We are collecting and characterising different strains to explore this yeast’s naturally occurring beneficial traits. These include the ability to grow in non-sterile conditions on a range of agricultural and food wastes and tolerance of the growth inhibitors present in these feedstocks.

We are using an adaptive laboratory evolution approach to exploit and enhance natural occurring traits. We are also developing a genomic and genetic toolkit and integrating phenotypic and metabolic data. This will help us understand how Metschnikowia pulcherrima responds to its environment and how we can manipulate these responses to improve our process.

This research phase is being carried out in the Department of Biology and Biochemistry at Bath.

Life cycle assessment (LCA) and techno-economic analysis (TEA)

We are developing a life-cycle assessment (LCA) model to assess the potential environmental impacts of the process. This will cover the production and collection of waste lignocellulosic material, through to multi-product incorporation into food, cosmetic/personal care, agricultural and bioenergy systems. We'll also develop a process model to evaluate technical design aspects and process economics.

This will be carried out in the Department of Mechanical Engineering at Bath across the lifetime of the project.

Publications

Santomauro, F; Whiffin, FM; Scott, RJ; Chuck, CJ; 2014. Low-cost lipid production by an oleaginous yeast cultured in non-sterile conditions using model waste resources, Biotechnology for Biofuels, 7, 34-43

Whiffin, F; Santomauro, F; Chuck, CJ; 2016. Towards a microbial palm oil substitute: oleaginous yeasts cultured on lignocellulose, Biofuels, Bioproducts and Biorefining, 10, 316-334

Fan, J; de Bruyn, M; Budarin, VL; Gronnow, MJ; Shuttleworth, PS; Breeden, S; Macquarrie, DJ; Clark, JH; 2013. 'Direct microwave-assisted hydrothermal depolymerisation of cellulose', Journal of the American Chemical Society, 135, 11728-11731

Project team

Principle Investigator

Project Manager

Co-investigators

Postdoctoral research staff