Lignocellulosic-biomass, a widely available renewable resource composed of cellulose, hemicellulose, lignin, and silica, have attracted growing attention as renewable, biocompatible, and tunable alternative feedstocks suitable for Pickering emulsions applications. Various lignocellulosic biomass-derived nanoparticles, such as lignin nanoparticles, cellulose nanocrystals, cellulose nanofibers, and silica nanoparticles, have demonstrated remarkable potential in emulsion systems due to their adjustable interfacial characteristics and biocompatibility. Despite rapid progress in this field, a comprehensive understanding of the structure–function relationships governing the stabilization of Pickering emulsions by lignocellulosic biomass-derived nanomaterials remains fragmented. This review consolidates recent advances in the synthesis, physicochemical characteristics, and interfacial behavior of lignocellulosic biomass-derived nanomaterials used in Pickering emulsions. Furthermore, recent advances in synergistic stabilization are highlighted, demonstrating that combining different nanomaterials enables multi-scale coupling between interfacial anchoring and bulk structuring, which significantly improving emulsion stability, mechanical integrity, and long-term performance. Key applications in drug delivery and catalysis are also discussed, where biomass-derived Pickering emulsions provide advantages in controlled release, enhanced mass transfer, and system sustainability. Finally, current challenges related to material variability, scalability, and safety are critically evaluated. This review advances a unified mechanistic framework for understanding and designing lignocellulosic biomass-derived nanomaterials in Pickering emulsions, providing guidance for the development of next-generation sustainable and high-performance emulsion systems.

Stillage is an acidic residue from ethanol production that has a high carbon load. Here, Ganoderma isolates were assessed for the treatment of rum stillage while producing biomass and associated metabolites. Isolates grew in 25% raw stillage, removing up to 73% of soluble organic carbon, 77% soluble nitrogen, and 74% phenolic compounds. Isolate G2 demonstrated faster removal of organic carbon and nitrogen. Biomass and metabolite production were benchmarked against a nutrient medium. In stillage, maximum values of the following were obtained: 8.2 g·L-1 biomass; 52.8% crude protein; 22.1 mg·g-1 extractable protein; antioxidants of 17.2 mg TE·g-1 (2,2'-azino-di-(3-ethylbenzothiazoline-6-sulfonic acid), ABTS) and 16.6 µmol Fe2+·g-1 (ferric reducing antioxidant power, FRAP); 2.9 mg GAE·g-1 phenolic compounds (gallic acid equivalents); 1.2% lipids; and 11% β-glucans. In the nutrient medium, the following were obtained: 6.9 g·L-1 biomass; 56.4% crude protein; 38.7 mg·g-1 extractable protein; antioxidants of 24.9 mg TE·g-1 (ABTS) and 25.9 µmol Fe2+·g-1 (FRAP); 6.0 mg GAE·g-1 phenolic compounds; 0.7% lipids; and 13% β-glucans. To our knowledge, this is the first report detailing the biomass metabolite content of Ganoderma mycelium using rum stillage. The production of edible biomass containing bioactive products demonstrates the potential of using Ganoderma strains to valorize this residue.

A transformação eficiente de biomassas lignocelulósicas, como o bagaço de cana-de-açúcar, em etanol celulósico exige um pré-tratamento termoquímico que melhore o acesso da celulase à celulose. A adição de co-solventes pode aumentar a eficiência desse pré-tratamento, mas sua recuperação é essencial para garantir a sustentabilidade econômica e ambiental do processo. Neste estudo, foi realizado o pré-tratamento do bagaço utilizando uma combinação de gama-valerolactona (GVL) e glicerol (Gli), avaliando-se a recuperação dos produtos e dos co-solventes por meio da indução de um sistema bifásico. O pré-tratamento foi conduzido a 120 °C por 60 minutos com diferentes proporções de co-solventes (80% GVL, 70% GVL/10% Gli, até 80% Gli). Foram analisados o rendimento dos sólidos residuais, sua composição, digestibilidade da celulose e produção de glicose. A condição com 60% GVL/20% Gli resultou em sólidos com digestibilidade de glucana de 94% e rendimento de glicose de 71%. Após diluição com água e adição de NaCl, formou-se um sistema bifásico com fase superior contendo os co-solventes e fase aquosa inferior rica em açúcares solúveis. As análises demonstraram que misturas com 60-70% de GVL permitem alta digestibilidade e recuperação do co-solvente (≥90%). Os resultados evidenciam o potencial dessas misturas como alternativa para o pré-tratamento de biomassas voltado à produção de etanol celulósico.

Pickering emulsions, stabilized by solid particles, offer a sustainable alternative to traditional surfactant-based emulsions, providing advantages in terms of biocompatibility and environmental safety. This study investigates the synthesis of lignin particles (LPs) derived from rice husk, an agricultural biomass waste, using solvent and pH shifting methods. The primary aim was to evaluate how different synthesis methods influence the structural properties of LPs and their performance as stabilizers for oil-in-water Pickering emulsions. LPs were synthesized through solvent shifting (using acetone, ethanol, and tetrahydrofuran) and pH shifting (at pH 4, 6, and 8) methods, and their particle size, surface charge, morphology, and emulsification performance were assessed. Solvent-shifted LPs synthesized with acetone and ethanol exhibited smaller particle sizes and more spherical shapes compared to pH-shifted LPs. The higher solubility of lignin in acetone and ethanol facilitated more controlled precipitation, resulting in smaller and better-dispersed particles. These solvent-shifted LPs also showed enhanced hydrophilicity and negative zeta potentials, improving emulsion stability by ensuring better particle adsorption at the oil-water interface. In contrast, pH-shifted LPs synthesized at lower pH (4 and 6) formed larger and more irregular particles due to rapid precipitation and reduced electrostatic repulsion at lower pH. Despite the larger size and aggregation, pH-shifted LPs demonstrated superior rheological properties, such as higher viscosity and storage modulus, indicating more stable, elastic emulsions. This study demonstrates that synthetic conditions are crucial in tailoring LP properties for enhanced emulsion stability, offering valuable insights for designing functional biomass derived lignin materials for food, cosmetic, and pharmaceutical applications.

Lanostene-derived triterpenoids and β-glucans are important metabolites in Ganoderma mushrooms associated with benefits to human health. The medicinal value of the Australian Ganoderma species remains unclear, with no data on triterpenoid distribution or glucan content. In the present study, 22 Australian Ganoderma specimens were analyzed for triterpenoid and glucan contents. Thirty-two triterpenoids were identified in the fruiting bodies of 19 of the specimens. Distinct patterns in triterpenoid distribution between laccate and matte fruiting bodies were observed, leading to the classification of four groups of Ganoderma. Most of the glucans in the Ganoderma fruiting bodies were β-glucans (~99%), with a nominal α-glucan content (~1%). The β-glucan content ranged from 19.5 to 43.5% (w/w). A range of antioxidant activities was observed for methanol extracts using the ABTS (1.8 to 8.4 mg GAE.g−1), DPPH (1.7 to 9.4 mg GAE/g−1) and FRAP (24.7 to 111.6 mmol FeSO4.g−1) assays, with four specimens presenting relatively high radical scavenging and reducing activities. For the first time, we demonstrated that Australian Ganoderma mushrooms contain medicinal triterpenoids, including ganoderic acid A, and we established a link between its distribution and the fruiting body morphology. However, further research is required to isolate diploid clones and determine factors that impact triterpenoid and glucan synthesis in these strains.

This study investigates the production of lignin/silica hybrid nanoparticles (LSNPs) from rice husks, an abundant agricultural waste, and their capacity to stabilize Pickering emulsions for biocatalysis. Lignin extracted from rice husks under alkaline conditions was co-precipitated with silica to produce LSNPs in the presence or absence of ethanol as a co-solvent. Characterization of LSNPs revealed that ethanol played a key role in forming uniform, spherical nanoparticles and minimizing aggregation. Lignin imparted amphiphilicity to the LSNPs, which significantly improved their capacity to form stable Pickering emulsions. LSNPs were able to form stable oil-in-water Pickering emulsions while droplet size and emulsion stability were influenced by LSNPs concentration, oil/water ratio, temperature and pH. LSNPs-stabilized Pickering emulsions were evaluated for lipase-mediated biosynthesis of phytosterol esters, which are plant bioactive compounds that can reduce dietary cholesterol uptake. LSNPs-stabilized emulsions provided 1.915 × 106 times larger interfacial areas compared to conventional biphasic systems which facilitated improved mass transfer and lipase activity. Under optimal conditions, LSNPs-stabilized Pickering emulsion systems delivered 90.6% phytosterol ester conversion in 4 h, compared to 10 h in biphasic systems. This research highlights the potential of sustainable, biomass-derived nanoparticles in Pickering emulsion applications and offers an environmentally friendly approach to produce bioactive compounds.

Abstract Giant Rat Tail Grass (GRT) is an introduced pasture plant species to Australia. The low palatability of GRT to livestock and its high seed count and drought tolerance are contributing factors to define this species as invasive pest. An alternative use for the plant would potentially alleviate the requirement of landholders to engage methods of eradication. The aim of this study was to collect and analyse the infrared fingerprint of GRT grain to assess its nutritional suitability for human consumption. Whole grain samples of GRT (n = 10) and teff (n = 3), a staple African grain, were analysed using attenuated total reflectance mid infrared spectroscopy (ATR-MIR spectroscopy). The MIR absorbance values of protein, lipids, and starch of each GRT and teff samples were calculated and compared. The MIR results indicated that GRT seeds have comparable levels of protein, lipids, and starch comparable to other commercially available seeds such as teff. The MIR spectra of GRT seeds showed that they have potential nutritional value for human consumption; however, the concentration of protein, starch and lipids was not determined. Further research is required to quantify the levels of these nutrients and suitability of GRT seeds for human consumption.

Single-use plastic hygiene control products used during red meat processing can have severe negative impacts on the environment and cannot be processed with offal during rendering into meat and bone meal. However, plastics made from protein could potentially solve this problem as the material would be safe to render. The objective of this work was to prepare blends of blood meal and polybutylene adipate terephthalate (PBAT) in the absence of water using the interaction between PBAT and protein as the plasticisation mechanism. The ratio of protein to PBAT (1:1.3), as well as the choice of compatibiliser (PBAT-g-IA), was critical to form a homogenous, compatibilised blend with mechanical properties suitable for injection-moulded hygeine control products. This blend had a tensile strenght of 11.2 MPa, a chord modulus of 492 MPa, and 10% elongation at break. Using less PBAT in the blend, or using Surlyn™ as a compatibiliser, resulted in blends that were either too difficult to process or with inferior mechancial properies. Using simulated rendering, the new material was indistinguishable from tallow or meat and bone meal, suggesting that hygeine control products made from this new material will degrade sufficiently to be safe to render with offal after red meat processing.

In this review, we offer our opinion of current and expected trends regarding the use of mushrooms and mycelia in food and feed. Mushrooms have provided food for millennia and production methods and species diversity have recently expanded. Beyond mushrooms, cultured fungal mycelia are now harvested as a primary product for food. Mushrooms and mycelia provide dietary protein, lipids and fatty acids, vitamins, fibre, and flavour, and can improve the organoleptic properties of processed foods (including meat analogues). Further, they are often key ingredients in nutritional or therapeutic supplements because of diverse specialised metabolites. Mycelia can also improve feed conversion efficiency, gut health, and wellbeing in livestock. New molecular tools, coupled with quality genetic data, are improving production technologies, enabling the synthesis of specialised metabolites, and creating new processing and valorisation opportunities. Production systems for submerged culture are capital intensive, but investment is required considering the scale of the protein market.

Heat haze-forming proteins are stable during winemaking and are typically removed via adsorption to bentonite. Proteolytic degradation is an alternative method to prevent wine-haze and offers the opportunity to reduce the environmental impacts and labor cost of the process. Herein, we describe the development of a production system for Botrytis cinerea proteases for the enzymatic degradation of heat haze-forming proteins. The effect of culture medium on the secretion of glucan by B. cinerea was investigated and methods to inactivate B. cinerea laccase in liquid culture medium were assessed. Protease production by B. cinerea was scaled up from 50 mL in shake flasks to 1 L in bioreactors, resulting in an increase in protease yield from 0.30 to 3.04 g L−1. Glucan secretion by B. cinerea was minimal in culture medium containing lactose as a carbon source and either lactic or sulfuric acid for pH control. B. cinerea laccases were inactivated by reducing the pH of culture supernatant to 1.5 for 1 h. B. cinerea proteases were concentrated and partially purified using ammonium sulfate precipitation. SWATH-MS identified aspartic acid protease BcAP8 amongst the precipitated proteins. These results demonstrate a simple, affordable, and scalable process to produce proteases from B. cinerea as a replacement for bentonite in winemaking. • Isolates of B. cinerea that produce proteases with potential for reducing wine heat-haze forming proteins were identified. • Media and fermentation optimization increased protease yield tenfold and reduced glucan secretion. • Low pH treatment inactivated laccases but not proteases.

The fermentation of leaf vegetable waste to produce animal feed reduces the environmental impact of vegetable production and transforms leaf vegetable waste into a commodity. We investigated the effect of exogenous probiotics and lignocellulose enzymes on the quality and microbial community of fermented feed (FF) produced from cabbage waste. The addition of exogenous probiotics resulted in increased crude protein (CP) content (p < 0.05), better odor (moderate organic acid and ethanol, with low ammonia-N, p < 0.05), and a lower relative abundance (RA) of pathogens (below 0.4%, p < 0.05) in FF, compared to without. With the addition of exogenous probiotics, only Pediococcus and Saccharomyces were enriched and symbiotic in FF; these were the keystone taxa to reduce the abundance of aerobic, form-biofilms, and pathogenic microorganisms, resulting in an efficient anaerobic fermentation system characterized by facultative anaerobic and Gram-positive bacterial communities, and undefined saprotroph fungal communities. Thus, inoculation of vegetable waste fermentation with exogenous probiotics is a promising strategy to enhance the biotransformation of vegetable waste into animal feed.

A sustainable future requires novel technologies that transform renewable feedstocks into liquid transport fuels, materials, and fine chemicals. Existing sugarcane biorefineries (sugar mills) generate a wide range of renewable feedstocks that can be readily converted into value-added products. Emerging biorefinery technologies offer further expansion of the products that can be generated in sugarcane biorefineries but biocatalysts that can use by-products and residues from these emerging technologies are needed to fully realize the opportunity these technologies represent. Filamentous fungi are versatile biocatalysts that can transform sugarcane biorefinery by-products and residues into a wide range of valuable products. This review provides an overview of sugarcane-based biorefining, existing and emerging processing technologies with application in sugarcane biorefineries; the residues and by-products generated in such a facility; and the opportunities to use filamentous fungi as biocatalysts to produce enzymes, organic acids, single cell protein, specialized metabolites, and animal feed.

The livestock sector is a fundamental part of the modern global economy and provides food, clothing, furnishings, and various other products. So as to ensure its resilience to changes in consumer expectations, cost of production, and environmental sustainability, the sector must shift to a circular economy model. Current strategies to recover value from wastes and low-value co-products from livestock industries yield limited value; hence, new technologies are required to upgrade wastes and co-products, and generate high-value products that can feed into the livestock value chain. Anaerobic digestion can convert high organic-content waste to biogas for energy and a stable nutrient-rich digestate that can be used as fertiliser. Microbial technologies can transform wastes to produce nutritionally advanced feeds. New materials from waste can also be produced for livestock industry-specific applications. While aiming to add commercial value, the successful implementation of these technologies will also address the environmental and productivity issues that are increasingly valued by producers and consumers.

Fructooligosaccharides (FOS) can be used as feed prebiotics, but are limited by high production costs. In this study, low-cost sugarcane molasses was used to produce whole-cell biocatalysts containing transfructosylating enzymes by Aureobasidium pullulans FRR 5284, followed by FOS production from molasses using the whole-cells of A. pullulans . A. pullulans in molasses-based medium produced cells and broth with a total transfructosylating activity of 123.6 U/mL compared to 61.0 and 85.8 U/mL in synthetic molasses-based and sucrose-based media, respectively. It was found that inclusion of glucose in sucrose medium reduced both transfructosylating and hydrolytic activities of the produced cells and broth. With the use of pure glucose medium, cells and broth had very low levels of transfructosylating activities and hydrolytic activities were not detected. These results indicated that A. pullulans FRR 5284 produced both constitutive and inducible enzymes in sucrose-rich media, such as molasses while it only produced constitutive enzymes in the glucose media. Furthermore, treatment of FOS solutions generated from sucrose-rich solutions using an invertase-deficient Saccharomyces yeast converted glucose to ethanol and acetic acid and improved FOS content in total sugars by 20–30%. Treated FOS derived from molasses improved the in vitro growth of nine probiotic strains by 9–63% compared to a commercial FOS in 12 h incubation. This study demonstrated the potential of using molasses to produce FOS for feed application.

Fructooligosaccharides (FOS) are a type of important prebiotics and produced by transfructosylating enzymes. In this study, sugarcane molasses was used as the substrate for production of transfructosylating enzymes by Aureobasidium pullulans FRR 5284. NaNO3 was a superior nitrogen source to yeast extract for production of transfructosylating enzymes by A. pullulans FRR 5284 and decreasing the ratio of NaNO3 to yeast extract nitrogen from 1:0 to 1:1 resulted in the reduction of the total transfructosylating activity from 109.8 U/mL to 82.5 U/mL. The addition of only 4.4 g/L NaNO3 into molasses-based medium containing 100 g/L mono- and di-saccharides resulted in total transfructosylating activity of 123.8 U/mL. Scale-up of the A. pullulans FRR 5284 transfructosylating enzyme production process from shake flasks to 1 L bioreactors improved the enzyme activity and productivity to 171.7 U/mL and 3.58 U/mL/h, 39% and 108% higher than those achieved from shake flasks, respectively. Sucrose (500 g/L) was used as a substrate for extracellular, intracellular, and total A. pullulans FRR 5284 transfructosylating enzymes, with a maximum yield of 61%. Intracellular, extracellular, and total A. pullulans FRR 5284 transfructosylating enzymes from different production systems resulted in different FOS profiles, indicating that FOS profiles can be controlled by adjusting intracellular and extracellular enzyme ratios and, hence prebiotic activity.

Abstract In this study, sugarcane molasses was used to produce transfructosylating enzymes by A. pullulans FRR 5284. It was found that NaNO3 was a better nitrogen source than yeast extract while exogeneous phosphorous was not needed. Adding only 4.4 g/L NaNO3 into the molasses medium containing 100 g/L sugars led to the highest total transfructosylating activity of 123.8 U/mL. Scale-up of the enzyme production process from shake flasks to 1 L reactor improved the enzyme activity and productivity to 171.7 U/mL and 3.58 U/mL/h, 39% and 108% higher than the corresponding activity and productivity from shake flasks, respectively. FOS production from 500 g/L sucrose led to the highest yields of ~ 61% using intracellular, extracellular, and total enzymes from shake flasks and the reactor. Enzymes from different sources led to very different FOS profiles, indicating that FOS profiles can be controlled by adjusting intracellular and extracellular enzyme ratios to adjust prebiotic activity.

Cyanidin-3-glucoside is a major anthocyanin in legumes, black rice, and purple potato, and has anti-inflammatory and antioxidant properties. In the present study, the effect of acylation on cyanidin-3-glucoside lipophilicity, stability, and antioxidant capacity was investigated. Cyanidin-3-glucoside was enzymatically acylated through transesterification with fatty acid esters to produce three monoacylated cyanidin-3-glucoside esters, cyanidin-3-(6″-n-octanoyl)-glucoside, cyanidin-3-(6″-lauroyl)-glucoside, and cyanidin-3-(6″-myristoyl)-glucoside. Cyanidin-3-(6″-n-octanoyl)-glucoside had the highest thermostability and photostability of the three cyanidin-3-glucoside esters. While the in vitro antioxidant activity of cyanidin-3-(6″-n-octanoyl)-glucoside was 7.5%-14.3% lower than that of cyanidin-3-glucoside (p < 0.05), its cellular antioxidant activity increased by 33.3% (p < 0.05). Further, while cyanidin-3-(6″-lauroyl)-glucoside had lower stability and in vitro antioxidant activity than that of cyanidin-3-(6″-n-octanoyl)-glucoside, its cellular antioxidant capacity was 125.9% and 69.4% higher than cyanidin-3-glucoside and cyanidin-3-(6″-n-octanoyl)-glucoside, respectively (p < 0.05). This study demonstrated that transesterification can be used to improve the stability and in vivo antioxidant activity of cyanidin-3-glucoside.

Background Sugarcane bagasse is a major source of lignocellulosic biomass, yet its economic potential is not fully realised. To add value to bagasse, processing is needed to gain access to the embodied recalcitrant biomaterials. When bagasse is stored in piles in the open for long periods it is colonised by microbes originating from the sugarcane, the soil nearby or spores in the environment. For these microorganisms to proliferate they must digest the bagasse to access carbon for growth. The microbial community in bagasse piles is thus a potential resource for the discovery of useful and novel microbes and industrial enzymes. We used culturing and metabarcoding to understand the diversity of microorganisms found in a uniquely undisturbed bagasse storage pile and screened the cultured organisms for fibre-degrading enzymes. Results Samples collected from 60 to 80 cm deep in the bagasse pile showed hemicellulose and partial lignin degradation. One hundred and four microbes were cultured from different layers and included a high proportion of oleaginous yeast and biomass-degrading fungi. Overall, 70, 67, 70 and 57% of the microbes showed carboxy-methyl cellulase, xylanase, laccase and peroxidase activity, respectively. These percentages were higher in microbes selectively cultured from deep layers, with all four activities found for 44% of these organisms. Culturing and amplicon sequencing showed that there was less diversity and therefore more selection in the deeper layers, which were dominated by thermophiles and acid tolerant organisms, compared with the top of pile. Amplicon sequencing indicated that novel fungi were present in the pile. Conclusions A combination of culture-dependent and independent methods was successful in exploring the diversity in the bagasse pile. The variety of species that was found and that are known for biomass degradation shows that the bagasse pile was a valuable selective environment for the identification of new microbes and enzymes with biotechnological potential. In particular, lignin-modifying activities have not been reported previously for many of the species that were identified, suggesting future studies are warranted.

The use of whole-cell biocatalyst for production of fructo-oligosaccharide (FOS) eliminates the need for costly enzyme recovery and purification. In this study, a novel Aureobasidium pullulans strain (FRR 5284) was identified from seven A. pullhdans strains as an efficient whole-cell biocatalyst for FOS production. The strain had a specific intracellular transfructosylating activity of 4.44 +/- 0.18 U/mg dry cells, one of the highest transfructosylating activities thus far reported for whole-cell biocatalyst. Under optimal conditions (pH 5.5 and 55 degrees C), only 5 g/L of dry cells and 3 h reaction time were required to achieve a FOS yield of 61 % from 50 % (w/v) sucrose. Incubation of sugarcane molasses with an invertase-free Saccharomyces cerevisiae prior to addition of A. pullulans whole-cell biocatalyst eliminated glucose inhibition and increased FOS yield from 44 % to 56 % in 1 h. This study has demonstrated that the novel A. pullulans FRR 5284 was an efficient source of whole-cell biocatalyst for FOS production and a promising strategy for transformation of sucrose and sugarcane molasses into a higher-value prebiotic.

Environmental pollution and the declining global supply of accessible fossil fuels are the key drivers of the search for alternative sources of energy. Biodiesel, a renewable liquid transport fuel, is commercially-produced using heterogeneous catalysts. Heterogeneous catalysts obtained from seashells appeared as promising alternatives thanks to their low preparation cost and increased efficiency in transesterification. In this study, shells from Chicoreus brunneus (known as Adusta murex) were calcined, hydrated, and dehydrated to produce CaO heterogeneous nanocatalyst for the transesterification of rice bran oil into biodiesel. Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, surface area measurement (Brunauer-Emmett-Teller method), and X-ray diffraction were used to characterise the seashell-derived catalyst. The properties of the rice bran oil-derived biodiesel (acid value, calorific value, density, oxidation stability, and flash point) conformed to the American Society of Testing and Materials (ASTM) D6751 and European EN 14214 biodiesel standards, except for kinematic viscosity. Therefore, the impact of the parameters used for production of the CaO heterogeneous nanocatalyst (calcination temperature and time) and the transesterification reaction (catalyst loading and methanol to rice bran oil ratio) on the kinematic viscosity of RBO-derived biodiesel were determined. A model for the transesterification process was developed using a combination of artificial neural networking with ant colony optimisation. The model predicted that C. brunneus-derived CaO catalyst prepared at 1100 °C for 72 min could be used to produce biodiesel from rice bran oil with a minimum kinematic viscosity (4.42 mm2 s−1) confirming to both the ASTM D6751 and EN 14214 biodiesel standards in a transesterification reaction operating with a 35:1 methanol to rice bran oil molar ratio and 0.5 wt% catalyst mass.