From Science & Research Turning CO 2 emissions into bioplastics: The cases of succinic and lactic in VIVALDI European research project VIVALDI has put together a multidisciplinary consortium to embrace the circularity by converting CO 2 emissions into bioplastics. Taking advantage of an innovative biobased value chain, biogenic CO 2 emissions are turned into industrially relevant organic acids, which can re-enter the production process flowchart of biorefineries. The yearly increasing industrial CO 2 emissions should not only be reduced or mitigated but should also be adopted as a novel feedstock. The need for CO 2 valorisation creates a demand for a novel industrial sector: CO 2 -based chemicals. This encourages industries to abandon the conventional linear structure (i.e. fossil-based reagents are transformed into products and wastes to be disposed of or treated) and switch to a circular concept where the wastes (gaseous or liquid) are transformed into novel sustainable compounds to be reused in the plant flowchart or to be sold externally. In the frame of a circular economy, the production of CO 2 - based bioplastics is a promising niche for novel business models and the market share of bioplastics is foreseen to increase rapidly [1]. The main factors driving the development of CO 2 -based bioplastics are: • the distinction from the current fluctuations of fossil fuel prices, • reduction of the carbon footprint, • decrease of the production costs and • reuse of the local materials and wastes. However, nowadays a direct production of bioplastics from CO 2 is not techno-economically feasible and the process requires multiple steps. The most sustainable and economic alternative is to first reduce CO 2 electrochemically to C1- building blocks (C1BBs) which will then serve as feedstock for their posterior microbial conversion into larger molecules with higher added-value [2]. Biobased products are shown to provide significant GHG savings (15–66 %) if we assume that they will replace 20 % of their fossil counterparts in the mid-term future [3]. Hermann et al. [4] predict a range of GHG savings of 1.5 to 3 tonnes of CO 2 per tonne of selected biobased products, assuming full substitution of the petrochemical equivalents and based on world production capacities in the years 1999/2000. VIVALDI aligns with this new CO 2 -based industry sector in the view of making it environmentally and economically competitive with its current twin, chemical production. The main objective of VIVALDI is the development, validation, and assessment of an innovative biobased value chain for the conversion of CO 2 emissions coming from biobased industries into added-value organic acids with different market shares: 3-hydroxypropionic, succinic, itaconic, and lactic acid. All of these selected organic acids have a variety of opportunities either as final products (i.e. replacement of current fossil-based chemical products) or as monomers (building blocks for novel biodegradable polymers). Succinic acid Succinic acid has been described as one of the top 12 building block chemicals and one of the 10 top chemicals to be produced from renewable resources [5,6]. Currently, more than 30 commercially valuable products can be synthetised from succinic acid in sectors varying from food (acidulant, flavour, and antimicrobial agent) and pharmaceuticals (excipient) to personal care (soaps) and chemicals (pesticides, dyes, and lacquers). Succinic acid could also replace other chemicals such as maleic anhydride in the production of various chemicals (e.g. 1,4-butanediol, γ-butyrolactone, tetrahydrofuran, N-methyl-2-pyrrolidone, 2-pyrrolidone, succinimide, or succinicesters). Succinic acid consumption increased from 28,500 tonnes in 2013 to 50,300 tonnes in 2017 and it is expected to reach 97,000 tonnes by 2024. The succinic acid market is expected to grow with an annual growth rate of 6.69 % from 2021 to 2027 [7]. Succinic acid is produced chemically by catalytic hydrogenation of fossil-based maleic acid or maleic anhydride. However, the chemical production possesses several environmental drawbacks and high economic costs: hydrogenation is energy-intensive due to the need to produce hydrogen and maleic acid is derived by hydrolysis of maleic anhydride (which is being produced by oxidation of benzene or butane) [8]. These issues can be mitigated by switching to bioproduction based on the bacterial fermentation of carbohydrates. Until recently, petrochemical-based succinic acid dominated the market and up to 2011 biobased succinic acid production was reported to be less than 5 % of the total production. However, these trends are changing fast and the market for biobased succinic acid is growing rapidly. In the case of companies producing biobased succinic acid, Succinity (Düsseldorf, Germany) reported a reduction of more than 60 % in GHG emissions and Roquette (Lestrem, France) reported a reduction of 52 % in CO 2 emissions as compared to petroleum-based succinic acid production. Lactic acid Lactic acid has a wide range of applications not only in the food production sector (preservative and pH adjusting agent) but also in personal care (moisturising and pH regulating) and packaging (precursor of propylene glycol). The global lactic acid market required was 1.220 million tonnes in 2016 and the demand is rising with prospections of it reaching 2 million tonnes in 2025 with annual growth of 16.2 % [9]. From 2021–2028, the lactic acid market is forecast to grow at 22 bioplastics MAGAZINE [01/22] Vol. 17
a compound annual growth rate of 8 % [10]. The main driver of the predicted large growth rate is the biobased production of polylactic acid (PLA), which is widely utilised e.g. in food packaging, mulch films, and rubbish bags. Lactic acid can be chemically synthesized e.g. by lactonitrile hydrolysis, basecatalysed degradation of sugars, and oxidation of propylene glycol [11]. Chemical production of lactic acid, however, leads to racemic mixtures, which restricts the use of the products in industries that require high enantiomeric purity. Fermentation enables stereoselective production of lactic acid and allows the use of cheap renewables as substrates, a lower amount of energy consumption and operation at milder temperatures. Fermentation processes account for around 80–90 % of the global lactic acid market [9]. Adom and Dunn (2016) reported lower GHG emissions (23–90 %) of bio-based ethyl lactate and PLA than with their respective fossil-derived compounds [12]. Lactic acid producer Corbion (Amsterdam, the Netherlands) states that their biobased LA production process has negative CO 2 emissions (–0.224 tonnes of CO 2 per tonne of LA). VIVALDI’s approach for the bioproduction of the organic acids is a yeast-based platform utilising methanol as the carbon source. Methanol will be produced via electrochemical reduction of CO 2 that has been captured By: By Albert Guisasola (Project coordinator), Mira Sulonen Universitat Autónoma de Barcelona Diethard Mattanovich University of Natural Resources and Life Sciences, Vienna Geert Bruggeman, Nutrition Sciences Roberto Vallero, Maria Teresa Riolo, Pieter Ravaglia, Novamont from emissions from biobased industries. The process thus integrates the CO 2 emissions in the production of addedvalue compounds that can then re-enter the production process of biomaterials. Methylotrophic yeast Pichia pastoris (Komagataella phaffii) is capable of oxidising methanol for energy production and assimilating it as the sole carbon source for growth and product formation. Selected gene sequences will be introduced to the genome of this naturally C1-utilizing yeast to direct its metabolism towards an optimal production of the desired organic acids. Synthetic biology technologies are applied to add the missing enzymes to convert metabolic intermediates into the target chemicals, as well as transport proteins that enable the release of the products from the yeast cells. Taking the bioconversion a step further, VIVALDI will also apply a synthetic autotrophic yeast strain that directly assimilates CO 2 and converts it into metabolites and biomass [13]. VIVALDI aims at a fast industrial adoption of its technologies and with this perspective the industrial partners have a crucial role in valorising the CO 2 -based products in the plant flowchart. CO 2 streams coming from biobased industries, such as the fermentation processes in Novamont (Novara, Italy) – a worldwide leader in the development and production of biomaterials from renewable sources From Science & Research bioplastics MAGAZINE [01/22] Vol. 17 23
