Production of the copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with varied composition using different nitrogen sources with Haloferax mediterranei

Bioconversion of dairy co-products to polyhydroxyalkanoates by halophilic microbes with salts and nutrients recycling

This study presented the cultivation of Haloferax mediterranei for polyhydroxyalkanoates (PHA) production from dairy co-products with spent salts recycling and provided the first insights of dissolved oxygen (DO) in regulating PHA biosynthesis by halophiles. PHA had yields up to 0.40 ± 0.02 g/g substrate from whey sugar and up to 0.17 ± 0.12 g/g substrate from delactosed permeate. A higher log-phase DO led to faster biosynthesis, but a lower final PHA production (2.0 ± 0.3 g/L) compared to lower DO levels (3.0 ± 0.1 g/L). This was later elucidated through mathematical modelling by the kinetic parameters and metabolic reaction rates. A novel approach was established to recycle up to 90 % salts and nutrients in the system and achieved consistent production and product quality. This study develops a sustainable biotechnology of converting dairy co-products to biomaterials, improve the economics of PHA and has the potential scalability for industrial applications.

Advanced Strategies for Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Production: PHA Synthase Homologous Overexpression in the Extremophile Haloferax mediterranei

Bioplastics such as poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) are promising alternatives to conventional plastics. However, the high production cost limits their industrial application. In this study, PHBV production was optimized in Haloferax mediterranei by the homologous overexpression of the key enzyme PHA synthase (PhaEC), resulting in the OEphaEC strain. The growth and PHBV production of OEphaEC compared with the parental strain (HM26) were evaluated in three culture media with different nitrogen sources (KNO3, NH4Cl, and casamino acids). The OEphaEC strain exhibited a 20% increase in PHBV production and a 40% increase in 3-hydroxyvalerate monomer (3HV) content in a defined medium with nitrate as a nitrogen source, as determined by GC-MS. Moreover, enzyme activity, measured spectrophotometrically, increased from 2.3 to 3.9 U/mg. Soluble and insoluble protein fractions were analysed to assess the overexpression of PHA synthase. Only PhaE was found in the insoluble protein fraction, where PHBV granules accumulate. Transmission electron microscopy (TEM) images confirmed a higher PHBV content in OEphaEC compared to the parental strain. These results demonstrate that the homologous overexpression of the key enzyme implicated in PHBV biosynthesis can enhance PHBV content, making its production competitive for industrial applications.

Microbial production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate), from lab to the shelf: A review

Polyhydroxyalkanoates (PHAs) are natural biopolyesters produced by microorganisms that represent one of the most promising candidates for the replacement of conventional plastics due to their complete biodegradability and advantageous material properties which can be modulated by varying their monomer composition. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] has received particular research attention because it can be synthesized based on the same microbial platform developed for poly(3-hydroxybutyrate) [P(3HB)] without much modification, with as high productivity as P(3HB). It also offers more useful mechanical and thermal properties than P(3HB), which broaden its application as a biocompatible and biodegradable polyester. However, a significant commercial disadvantage of P(3HB-co-3HV) is its rather high production cost, thus many studies have investigated the economical synthesis of P(3HB-co-3HV) from structurally related and unrelated carbon sources in both wild-type and recombinant microbial strains. A large number of metabolic engineering strategies have also been proposed to tune the monomer composition of P(3HB-co-3HV) and thus its material properties. In this review, recent metabolic engineering strategies designed for enhanced production of P(3HB-co-3HV) are discussed, along with their current status, limitations, and future perspectives.

Food wastes for bioproduct production and potential strategies for high feedstock variability

Unavoidable food wastes could be an important feedstock for industrial biotechnology, while their valorization could provide added value for the food processor. However, despite their abundance and low costs, the heterogeneous/mixed nature of these food wastes produced by food processors and consumers leads to a high degree of variability in carbon and nitrogen content, as well as specific substrates, in food waste hydrolysate. This has limited their use for bioproduct synthesis. These wastes are often instead used in anaerobic digestion and mixed microbial culture, creating a significant knowledge gap in their use for higher value biochemical production via pure and single microbial culture. To directly investigate this knowledge gap, various waste streams produced by a single food processor were enzymatically hydrolyzed and characterized, and the degree of variability with regard to substrates, carbon, and nitrogen was quantified. The impact of hydrolysate variability on the viability and performance of polyhydroxyalkanoates biopolymers production using bacteria (Cupriavidus necator) and archaea (Haloferax mediterranei) as well as sophorolipids biosurfactants production with the yeast (Starmerella bombicola) was then elucidated at laboratory-scale. After which, strategies implemented during this experimental proof-of-concept study, and beyond, for improved industrial-scale valorization which addresses the high variability of food waste hydrolysate were discussed in-depth, including media standardization and high non-selective microbial organisms growth-associated product synthesis. The insights provided would be beneficial for future endeavors aiming to utilize food wastes as feedstocks for industrial biotechnology.

Bioplastic Production from Agri-Food Waste through the Use of Haloferax mediterranei: A Comprehensive Initial Overview

The research on bioplastics (both biobased and biodegradable) is steadily growing and discovering environmentally friendly substitutes for conventional plastic. This review highlights the significance of bioplastics, analyzing, for the first time, the state of the art concerning the use of agri-food waste as an alternative substrate for biopolymer generation using Haloferax mediterranei. H. mediterranei is a highly researched strain able to produce polyhydroxybutyrate (PHB) since it can grow and produce bioplastic in high-salinity environments without requiring sterilization. Extensive research has been conducted on the genes and pathways responsible for PHB production using H. mediterranei to find out how fermentation parameters can be regulated to enhance cell growth and increase PHB accumulation. This review focuses on the current advancements in utilizing food waste as a substitute for costly substrates to reduce feedstock expenses. Specifically, it examines the production of biomass and the recovery of PHB from agri-food waste. Furthermore, it emphasizes the characterization of PHB and the significance of hydroxyvalerate (HV) abundance in the formation of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) copolymer. The downstream processing options are described, and the crucial factors associated with industrial scale-up are assessed, including substrates, bioreactors, process parameters, and bioplastic extraction and purification. Additionally, the economic implications of various options are discussed.

ALACEN: A Holistic Herbaceous Biomass Fractionation Process Attaining a Xylose-Rich Stream for Direct Microbial Conversion to Bioplastics

Lignocellulose biorefining is a promising technology for the sustainable production of chemicals and biopolymers. Usually, when one component is focused on, the chemical nature and yield of the others are compromised. Thus, one of the bottlenecks in biomass biorefining is harnessing the maximum value from all of the lignocellulosic components. Here, we describe a mild stepwise process in a flow-through setup leading to separate flow-out streams containing cinnamic acid derivatives, glucose, xylose, and lignin as the main components from different herbaceous sources. The proposed process shows that minimal degradation of the individual components and conservation of their natural structure are possible. Under optimized conditions, the following fractions are produced from wheat straw based on their respective contents in the feed by the ALkaline ACid ENzyme process: (i) 78% ferulic acid from a mild ALkali step, (ii) 51% monomeric xylose free of fermentation inhibitors by mild ACidic treatment, (iii) 82% glucose from ENzymatic degradation of cellulose, and (iv) 55% native-like lignin. The benefits of using the flow-through setup are demonstrated. The retention of the lignin aryl ether structure was confirmed by HSQC NMR, and this allowed monomers to form from hydrogenolysis. More importantly, the crude xylose-rich fraction was shown to be suitable for producing polyhydroxybutyrate bioplastics. The direct use of the xylose-rich fraction by means of the thermophilic bacteria Schlegelella thermodepolymerans matched 91% of the PHA produced with commercial pure xylose, achieving 138.6 mgPHA/gxylose. Overall, the ALACEN fractionation method allows for a holistic valorization of the principal components of herbaceous biomasses.

Enhancing polyhydroxyalkanoate production in Cupriavidus sp. L7L through wcaJ gene deletion

Cupriavidus sp. L7L synthesizes a high content of ductile polyhydroxyalkanoate. However, during fermentation, the medium's viscosity gradually increases, eventually reaching a level similar to 93 % glycerol, leading to fermentation termination and difficulties in cell harvest. A non-mucoid variant was isolated from a mini-Tn5 mutant library with the transposon inserted at the promoter sequence upstream of the wcaJ gene. Deletion of wcaJ eliminated the mucoid-colony appearance. The complementation experiment confirmed the association between wcaJ gene expression and mucoid-colony formation. Additionally, the wild-type strain exhibited a faster specific growth rate than the deletion strain using levulinate (Lev) as a carbon source. In fed-batch fermentation, Cupriavidus sp. L7L∆wcaJ showed similar PHA content and monomer composition to the wild-type strain. However, the extended fermentation time resulted in a 42 % increase in PHA concentration. After fed-batch fermentation, the deletion strain's medium had only 8.75 % of the wild-type strain's extracellular polymeric substance content. Moreover, the deletion strain's medium had a much lower viscosity (1.04 mPa·s) than the wild-type strain (194.7 mPa·s), making bacterial cell collection easier through centrifugation. In summary, Cupriavidus sp. L7L∆wcaJ effectively addressed difficulties in cell harvest, increased PHA production, and Lev-to-PHA conversion efficiency, making these characteristics advantageous for industrial-scale PHA production.

Process Development of Polyhydroxyalkanoates Production by Halophiles Valorising Food Waste

Polyhydroxyalkanoates (PHA) is an emerging biodegradable plastic family that can replace a broad spectrum of conventional thermoplastics and is promising in the sustainable process development and valorization of organic waste. This study established a novel production system of PHA from food waste through halophilic microbial fermentation with spent medium recycling. The essential processing parameters for batch cultivation of Haloferax mediterranei were optimized for food waste substrate (a 40 g/L loading and 2.5 vvm of aeration), which achieved a yield of 0.3 g PHA/g COD consumed. A batch bioreactor system was developed, which produced 7.0 ± 0.7 g/L cell dry mass and 4.5 ± 0.2 g/L PHA with a 20% dissolved oxygen (DO) level. A DO above 50% saturation resulted in faster cell growth and similar cell mass production but 25% less PHA production. The spent saline medium, treated with H2O2 and rotary evaporation, was successfully reused for four consecutive batches and provided consistent PHA concentrations and product qualities.

Exploitation of wasted bread as substrate for polyhydroxyalkanoates production through the use of Haloferax mediterranei and seawater

The use of the halophile microorganism Haloferax mediterranei, able to synthesize poly(hydroxybutyrate-hydroxyvalerate) (PHBV), is considered as a promising tool for the industrial production of bioplastic through bioprocessing. A consistent supplementation of the growth substrate in carbohydrates and minerals is overall necessary to allow its PHBV production. In this work, wasted bread was used as substrate for bioplastic production by microbial fermentation. Instead of the consistent and expensive minerals supplement required for Hfx. mediterranei DSM1411 growth, microfiltered seawater was added to the wasted bread-derived substrate. The suitable ratio of wasted bread homogenate and seawater, corresponding to 40:60, was selected. The addition of proteases and amylase to the bread homogenate promoted the microbial growth but it did not correspond to the increase of bioplastic production by the microorganism, that reach, under the experimental conditions, 1.53 g/L. An extraction procedure of the PHBV from cells, based on repeated washing with water, followed or not by a purification through ethanol precipitation, was applied instead of the conventional extraction with chloroform. Yield of PHBV obtained using the different extraction methods were 21.6 ± 3.6 (standard extraction/purification procedure with CHCl3:H2O mixture), 24.8 ± 3.0 (water-based extraction), and 19.8 ± 3.3 mg PHAs/g of wasted bread (water-based extraction followed by ethanol purification). Slightly higher hydroxyvalerate content (12.95 vs 10.78%, w/w) was found in PHBV obtained through the water-based extraction compared to the conventional one, moreover, the former was characterized by purity of 100% (w/w). Results demonstrated the suitability of wasted bread, supplemented with seawater, to be used as substrate for bioplastic production through fermentation. Results moreover demonstrated that a solvent-free extraction, exclusively based on osmotic shock, could be used to recover the bioplastic from cells.

Simplified engineering design towards a competitive lipid-rich effluents valorization

Medium- and long-chain fatty acids and glycerol contained in the oily fraction of many food-industry effluents are excellent candidates to produce biobased high-value triacylglycerides (TAGs) and polyhydroxyalkanoates (PHAs). The typical process configuration for TAGs recovery from lipid-rich streams always includes two steps (culture enrichment plus storage compounds accumulation) whereas, for PHAs production, an additional pretreatment of the substrate for the obtainment of soluble volatile fatty acids (VFAs) is required. To simplify the process, substrate hydrolysis, culture enrichment, and accumulation (TAG and PHA storage) were coupled here in a single sequencing batch reactor (SBR) operated under the double growth limitation strategy (DGL) and fed in pulses with industrial waste fish oil during the whole feast phase. When the SBR was operated in 12 h cycles, it was reached up to 51 wt % biopolymers after only 6 h of feast (TAG:PHA ratio of 50:51; 0.423 Cmmol_BIOP/Cmmol_S). Daily storage compound production was observed to be over 25% higher than the reached when enrichment and accumulation stages were carried in separate operational units. Increasing the feast phase length from 6 to 12 h (18 h cycle) negatively affected the DGL strategy performance and hence system storage capacity, which was recovered after also extending the famine phase in the same proportion (24 h cycle). Besides, the carbon influx during the feast phase was identified as a key operational parameter controlling storage compounds production and, together with the C/N ratio, culture selection. The different cycle configurations tested clearly modulated the total fungal abundances without no significant differences in the size of the bacterial populations. Several PHA and TAG producers were found in the mixed culture although the PHA and TAG productions were poorly associated with the increased relative abundances (RAs) of specific operational taxonomic units (OTUs).

Coupling Magnetic Field and Salinity Upshock To Improve Polyhydroxyalkanoate Productivity by Haloferax mediterranei Feeding on Molasses Wastewater

Low polyhydroxyalkanoate (PHA) volumetric productivity from wastewater limits low-cost PHA production. To resolve this problem, an external magnetic field (MF) coupled with upshock salinity was applied to PHA production by Haloferax mediterranei (family Halobacteriaceae). Elevating the fermentation salinity over the optimal growth salinity (200 g/L) increased the PHA cell content while inhibiting cell proliferation, decreasing volumetric productivity. When a MF of 50 mT in 300 g/L salinity was applied, H. mediterranei proliferation and PHA cell content were promoted, leading to a 7.95% increase in PHA volumetric productivity in synthetic molasses wastewater and a 13.82% increase in glucose feeding compared with those in 200 g/L salinity. Under the MF, osmotic pressure regulation was activated by accumulating K⁺ and increasing betaine synthesis. The maximum betaine content increased by 74.33% in 300 g/L salinity with a 50-mT MF compared with that in 200 g/L salinity. When a 50-mT MF in 300 g/L salinity was applied, the malondialdehyde (MDA) content decreased by 32.66% and the activity of superoxide dismutase (SOD) increased by 46.89%, which reduced the oxidative damage. This study provides a new solution to enhance PHA volumetric productivity by MF and an insight into the magnetic effects of H. mediterranei. IMPORTANCE The obstacle to replacing petroplastics with PHA is its high production cost. To increase the fermentation economy, a novel strategy of coupling a MF with salinity upshock was applied, which enhanced the PHA volumetric productivity of H. mediterranei in fermenting molasses wastewater. The magnetic effect of H. mediterranei was found at a MF of 50 mT, which improved the salt tolerance of H. mediterranei and reduced the oxidative damage induced by the elevated salinity, thereby promoting proliferation and PHA cell content. This is the first time a technical method for enhancing PHA volumetric productivity by means of a MF has been proposed. Such a strategy can advance the utilization of H. mediterranei for the industrial production of PHA using organic wastewater.

Evaluating haloarchaeal culture media for ultrahigh-molecular-weight polyhydroxyalkanoate biosynthesis by Haloferax mediterranei

A series of culture media for haloarchaea were evaluated to optimize the production of ultrahigh-molecular-weight (UHMW) poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) by Haloferax mediterranei. Cells of H. mediterranei grew (> 1 g/L of dry cell weight) and accumulated PHBV upon flask cultivation in 10 medium types with neutral pH and NaCl concentration > 100 g/L. Molecular weight and compositional analysis revealed that the number-average molecular weight (M_n) of PHBV produced with six selected types of media ranged from 0.8 to 3.5 × 10⁶ g/mol and the 3-hydroxyvalerate (3HV) composition ranged from 8 to 36 mol%. Cultivation in two NBRC media, 1214 and 1380, resulted in the production of PHBV with an M_n of more than 3.0 × 10⁶ g/mol and a weight-average molecular weight of more than 5.0 × 10⁶ g/mol, indicating the production of UHMW-PHBV. These culture media contained small amount of complex nutrients like yeast extract and casamino acids, suggesting that H. mediterranei likely produced UHMW-PHBV on poor nutrient condition. Haloferax mediterranei grown in NBRC medium 1380 produced PHBV with the highest 3HV composition. A solvent-cast film of UHMW-PHBV with 26.4 mol% 3HV produced from 1-L flask cultivation with NBRC medium 1380 was found to be flexible and semi-transparent. Thermal analysis of the UHMW-PHBV cast film revealed melting and glass-transition temperatures of 90.5 °C and - 2.7 °C, respectively. KEY POINTS: • Haloarchaeal culture media were evaluated to produce UHMW-PHBV by H. mediterranei. • UHMW-PHBV with varied molecular weight was produced dependent on culture media. • Semi-transparent film could be made from UHMW-PHBV with 26.4 mol% 3HV.

Utilizing the crop waste of date palm fruit to biosynthesize polyhydroxyalkanoate bioplastics with favorable properties

Polyhydroxyalkanoate (PHA), a family of biodegradable and renewable biopolymers that could potentially play a significant role in bioeconomy. In this study we investigated the potential of date waste (DW) biomass as feedstock to produce PHA by the halophilic archaeon Haloferax mediterranei. The concentration of essential trace elements for H. mediterranei cells during growth and PHA biopolymer accumulation was optimized. A maximum cell dry mass of (CDM) (12.8 g L^-1) and PHA concentration of (3.20 g L^-1) were achieved in DW extract media that was not supplemented with trace elements, indicating that DW is a promising source for trace elements. The cultivation was scaled-up to fed-batch bioreactor fermentations under non-sterile conditions and resulted in CDM and PHA content of 18.0 g L^-1 and 25%, respectively. The produced PHA was confirmed to be poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with high 3-hydroxyvalerate (3 HV) content of 18.0 mol%. This 3 HV molar percent was achieved without the addition of expensive precursors. The PHBV is of high molecular weight (746.0 kDa) and narrow polydispersity (PDI = 1.5), and displayed reduced melting at 148.1 °C. The X-ray diffraction (XRD) analysis showed that the PHBV has amorphous nature which increases the degradation rates and workability of the biopolymer. The isotopic ratio ¹³C/¹²C (δ ¹³C) for PHBV was found to be - 19.1‰, which indicated that H. mediterranei prefers lighter bonds to break and uses the lighter atoms for the biosynthesis of PHBV.

Anabolism of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by Cupriavidus necator DSM 545 from spent coffee grounds oil

Oil extracted from spent coffee grounds (SCG) [yield 16.8 % (w/w)] was discovered to be a highly suitable carbon substrate for the biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3 HV)] copolymers by Cupriavidus necator DSM 545 in the absence of any traditional 3 HV precursors. Cells cultivated in a 3 L bioreactor (batch) reached a total biomass concentration of 8.9 g L^-1 with a P(3HB-co-3 HV) (6.8 mol% 3 HV) content of 89.6 % (w/w). In contrast, cells grown on sunflower oil reached a total biomass concentration of 9.4 gL^-1 with a P(3HB-co-3 HV) (0.2 mol% 3 HV) content of 88.1 % (w/w). It is proposed that the organism could synthesize 3 HV monomers from succinyl CoA, an intermediate of the tricarboxylic acid (TCA) cycle, via the succinate-propionate metabolic pathway.

Optimization of nitrogen source supply for enhanced biosynthesis and quality of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by extremely halophilic archaeon Haloferax mediterranei

The extreme halophilic archaeon, Haloferax mediterranei can accumulate polyhydroxyalkanoate (PHA) from different renewable resources. To enhance the biosynthesis and quality of PHA, H. mediterranei cultivation media was optimized at different C/N ratios using glucose as the main carbon source. Three sets of media (yeast extract [YE], NH₄ Cl and combination of YE and NH₄ Cl) were prepared at different nitrogen concentrations to achieve C/N ratios of 9, 20, and 35, respectively. The media containing YE (organic nitrogen source) produced a higher growth rate of H. mediterranei than NH₄ Cl (inorganic source) at all tested C/N ratios. The highest PHA accumulation (18.4% PHA/cell dry mass) was achieved in a media that combined YE with NH₄ Cl at a C/N ratio of 20. Analysis of the produced polymers revealed the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) with different 3-hydroxyvalerate (3HV) content. The polymers produced from YE and the combined media have greater 3HV content (10 mol%) than those polymers recovered from NH₄ Cl (1.5 mol%). Resultingly, PHBHV from YE and the combined media displayed reduced melting points at 144°C. The nitrogen type/concentration was found to also have an impact on the molecular weights and polydispersity indices of the produced biopolymers. Furthermore, the tensile strengths were found to vary with the best tensile strength (14.4 MPa) being recorded for the polymer recovered from YE at C/N = 9. Interestingly, the tensile strength of PHBHV was significantly higher than petroleum-based polyethylene (13.5 MPa), making it a much more suitable bioplastic for industrial application.

Current developments on polyhydroxyalkanoates synthesis by using halophiles as a promising cell factory

Plastic pollution is a severe threat to our environment which necessitates implementation of bioplastics to realize sustainable development for a green world. Polyhydroxyalkanoates (PHA) represent one of the potential candidates for these bioplastics. However, a major challenge faced by PHA is the high production cost which limits its commercial application. Halophiles are considered to be a promising cell factory for PHA synthesis due to its several unique characteristics including high salinity requirement preventing microbial contamination, high intracellular osmotic pressure allowing easy cell lysis for PHA recovery, and capability to utilize wide spectrum of low-cost substrates. Optimization of fermentation parameters has made it plausible to achieve large-scale production at low cost by using halophiles. Further deeper insights into halophiles have revealed the existence of diversified and even novel PHA synthetic pathways within different halophilic species that greatly affects PHA type. Thus, precise metabolic engineering of halophiles with the help of advanced tools and strategies have led to more efficient microbial cell factory for PHA production. This review is an endeavour to summarize the various research achievements in these areas which will help the readers to understand the current developments as well as the future efforts in PHA research.

Polyhydroxyalkanoate Biosynthesis at the Edge of Water Activitiy-Haloarchaea as Biopolyester Factories

Haloarchaea, the extremely halophilic branch of the Archaea domain, encompass a steadily increasing number of genera and associated species which accumulate polyhydroxyalkanoate biopolyesters in their cytoplasm. Such ancient organisms, which thrive in highly challenging, often hostile habitats characterized by salinities between 100 and 300 g/L NaCl, have the potential to outperform established polyhydroxyalkanoate production strains. As detailed in the review, this optimization presents due to multifarious reasons, including: cultivation setups at extreme salinities can be performed at minimized sterility precautions by excluding the growth of microbial contaminants; the high inner-osmotic pressure in haloarchaea cells facilitates the recovery of intracellular biopolyester granules by cell disintegration in hypo-osmotic media; many haloarchaea utilize carbon-rich waste streams as main substrates for growth and polyhydroxyalkanoate biosynthesis, which allows coupling polyhydroxyalkanoate production with bio-economic waste management; finally, in many cases, haloarchaea are reported to produce copolyesters from structurally unrelated inexpensive substrates, and polyhydroxyalkanoate biosynthesis often occurs in parallel to the production of additional marketable bio-products like pigments or polysaccharides. This review summarizes the current knowledge about polyhydroxyalkanoate production by diverse haloarchaea; this covers the detection of new haloarchaea producing polyhydroxyalkanoates, understanding the genetic and enzymatic particularities of such organisms, kinetic aspects, material characterization, upscaling and techno-economic and life cycle assessment.