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OPTimized conversion of residual wheat straw to bio-ISObutene for bio based CHEMicals

Periodic Reporting for period 3 - OPTISOCHEM (OPTimized conversion of residual wheat straw to bio-ISObutene for bio based CHEMicals)

Reporting period: 2020-06-01 to 2022-12-31

Biomass is frequently considered as an alternative feedstock for substitution of fossil oil, as it may allow to mitigate climate change and resources depletion. This biomass may be derived from agricultural residues, forestry residues or agroindustry residues, all of them containing cellulose which is the most abundant organic polymer on earth. However, direct substitution is not possible, and processes are needed for a preliminary conversion of biomass into intermediate products: the industrial biology sector provides such processes. As a feedstock for these processes, ligno-cellulosic sugars represent an attractive alternative to traditional sugars as they can be made from widespread resources, and do not compete with food or feed production.

Technologies currently used to produce ligno-cellulosic sugars deliver complex syrups containing inhibitors which hamper the fermentation performances and impurities which make the purification step for the desired molecule more difficult. Furthermore, biomass to building blocks technologies frequently propose to deliver molecules displaying characteristics that are significantly different from those of their fossil-based equivalents. Their use implies the need for heavy modifications and investments, taking place downstream in the value chain.

Isobutene is an important building block currently produced and used in the petrochemical industry for lubricants, rubbers, cosmetics, plastics, solvents, and fuels applications. Its global market is more than 15Mt a year and is growing 2.5% a year. At the same time, customers of fossil-based isobutene-derived goods are asking for more renewables.

The overall goal of OPTISOCHEM was to demonstrate the performance, the reliability and the environmental and socio-economic sustainability, of the entire value chains for the transformation of wheat straw, into bio-isobutene and derivatives. The project addressed two different isobutene derivatives families: oligomers and polyisobutylenes. These products are currently requested by the market for a wide array of applications. Presently these needs are satisfied by commercial processes designed to be fed with fossil-based isobutene. The project demonstrated that these needs could be satisfied by the existing processes when fed with bio-based isobutene from sustainably extracted wheat straw. The outcome of the project is to provide the backbone for a first profitable small scale plant for niche market prior to subsequent first of its kind 30kt per year flagship project and a series of numerous additional plants afterwards.
During the project duration, and according to the Gantt chart, all partners contributed to progress towards the objectives and all milestones were achieved.
• P01-GBE main result during the project:
- The strain achieving M03 performances.
- Deliveries of bio-IBN for conversion activities
- Feasibility of fermentative IBN as feed for DIB & TIB
- Creation of product brands
- One patent application
- Scale-up of the Alternative protocol with immediate profitability on niche markets.
- Further improvement of the IBN metabolic pathway were identified and are underway to:
i) Decorrelate growth and production to reduce the use of expensive ingredients (yeast extracts) and increase IBN-producing biomass level
ii) Improve stability of sugar consumption over time
iii) Increase productivity of IBN metabolic pathway
These results may allow P01-GBE to progress towards a small scale first profitable plant with profitability on niche markets that may allow to de-risk future bigger plant as stated in the hereunder exploitation plan.
• P02-CLA main result during the project is a purification process which allows to remove unexpected impurities from the hydrolysate which can be used for new types of fermentation than the one it was designed for, i.e. ethanol production.
This result can allow P02-CLA to offer substrate for fermentation activities different than ethanol.
• P03-INE main results during RP2 are:
- Production of experimental bio-PIB material in its Lavera’s pilot plant, using GBE’s bio-IBN as a feedstock (Milestone M08)
- Knowledge regarding acceptance of bio-based end-products by customers (Milestone M10).
These results may allow P03-INE to start preparing its marketing strategy for new offers based on bio-IBN.
• P04-TEC and P06-IPS main results are optimized process flow and heat and mass balances. This is new knowledge that can be used for further commercial plant design.
• P05-JKU main exploitable result is the LCA according to ISO standard 14040 of fermentative isobutene routes. This can be utilized in other projects and in conferences.
The exploitation plan for the final exploitable results remains within the strategy which was described in the initial proposal. P01-GBE, P02-CLA, P04-TEC and P06-IPS can exploit the final results with the construction of a first of its kind commercial plant which can be for example co-located on PO2-CLA site in Romania where a straw-to-ethanol plant was commissioned, or on a PO1-GBE site in France where a beet-to-bio-isobutene plant construction is being considered. On its side P03-INE is well positioned to envisage a business on bio-isobutene derivatives, using bio-isobutene from the first of its kind straw-to-bio-isobutene commercial plant.
There were several unforeseen issues that were identified during the project which were then solved, including:
- A new hydrolysate grade was created which is almost free from unexpected phenolic inhibitors;
- Implementation of an alternative “two-stage” fermentation protocol to increase IBN productivity performances;
- Was also identified the co-production by the strain of an endogenous inhibitor and discovered and successfully implemented a metabolic solution to get rid from this endogenous inhibitor.
Overall, the project successfully produced:
- bio-IBN as a building-block molecule
- together with several derivatives
- building-block molecule and derivatives were qualified for various applications (D6.5 Stakeholder evaluation report).
P1 GBE could create product brands and apply for patent.
Finally, Economical, environmental, and social impact studies were successfully performed, showing that, while targeted cost of production could not be matched, an alternative solution emerged for allowing a first profitable small plant project addressing niche markets. This small plant project will allow to de-risk the larger scale first of its kind commercial plant.
So far, both, traditional-sugars-based and hydrolysate-based isobutene show a significantly better greenhouse gas performance than fossil isobutene. It has also been identified that important parameters for maximizing the greenhouse gas saving of bio-isobutene compared to fossil isobutene are sugar feedstock and process energy generation.
The project allowed creating a new building block and 2 new bio-based materials with increased yield, reduced cost, reduced energy consumption and for delivering this innovation which meets the needs of end-consumers to the European and global markets. This paves the way for strengthening the competitiveness and growth of companies and creating employment in rural areas.
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