Commercial Scale Research Articles

Canadian productivity growth: Stuck in the oil sands

AbstractWe study the behaviour of Canadian Total Factor Productivity (TFP) growth over the past 60 years. We find that the observed stagnation during the last 20 years is accounted for entirely by the oil sector. Higher oil prices made capital‐intensive sources of oil like the oil sands viable to extract on a commercial scale. However, the greater input required per barrel of oil slowed TFP growth. Comparing Canadian TFP growth with that of the United States and Norway reinforces these results. However, our result should not be interpreted to carry any welfare implications.

Quantifying soil organic carbon after biochar application: how to avoid (the risk of) counting CDR twice?

Pyrogenic carbon capture and storage (PyCCS), which comprises the production of biomass, its pyrolysis, and the non-oxidative use of the biochar to create carbon sinks, has been identified as a promising negative emission technology with co-benefits by improving soil properties. Using biochar as a soil additive becomes increasingly common as farmers seek methods for soil improvement and climate change adaptation. Concurrently, there is growing interest in quantifying soil organic carbon (SOC) at the level of individual plots to remunerate farmers for their good agricultural practices and the resulting (temporary) carbon dioxide removal (CDR). However, methods currently applied in routine analysis quantify SOC, irrespective of its speciation or origin, and do not allow to distinguish biochar-C from SOC. As certification of PyCCS-derived CDR is already established using another quantification method (i.e., analysis of biochar-C content, tracking and registration of its application, and offsetting of carbon expenditures caused by the PyCCS process), the analysis of biochar-C as part of SOC may result in double counting of CDR. Hence, the objectives of this review are (1) to compare the physicochemical properties and the quantities of biochar and SOC fractions on a global and field/site-specific scale, (2) to evaluate the established methods of SOC and pyrogenic carbon (PyC) quantification with regard to their suitability in routine analysis, and (3) to assess whether double counting of SOC and biochar C-sinks can be avoided via analytical techniques. The methods that were found to have the potential to distinguish between non-pyrogenic and PyC in soil are either not fit for routine analysis or require calibration for different soil types, which is extremely laborious and yet to be established at a commercial scale. Moreover, the omnipresence of non-biochar PyC in soils (i.e., from forest fires or soot) that is indistinguishable from biochar-C is an additional challenge that can hardly be solved analytically. This review highlights the risks and limits of only result-based schemes for SOC certification relying on soil sampling and analysis. Carbon sink registers that unite the (spatial) data of biochar application and other forms of land-based CDR are suggested to track biochar applications and to effectively avoid double counting.

Evaluation of a self-cleaning larval rearing tank to improve production of two marine finfish species

The goal of this study was to test a commercial scale larval rearing tank with a self-cleaning mechanism to improve larval rearing success for marine fish. Four trials were conducted to compare the performance of a self-cleaning tank (SCT) to a control (CON) larval rearing tank. Two trials were conducted using California yellowtail (CYT; Seriola dorsalis) and two were conducted using white seabass (WSB; Atractoscion nobilis). Metrics collected for each trial included, larval growth, survival, bacterial colony counts (Vibrio spp.), total suspended solids concentrations, and labor (time spent siphoning the tanks). There were no differences in growth between tanks for either species. CYT survival in Trial 1 resulted in better survival in the CON tank (56.8%) than in the SCT (32.8%). WSB survival in both Trial 1 and 2 was higher in the SCT than in the CON tank (35.5% versus 26.9% and 15.8% versus 10.1%, respectively). We suspected that the cleaning arm was likely causing early mortality in both species (between 0 and 16 days post hatch; dph), therefore, Trial 2 involved only cycling the arm twice per day for one hour until the larvae were 16 dph. This modification yielded improved survival in the SCT (60.5%) than CON tank (47.1) but only for the CYT. Total suspended solids were higher in the CON tank for both species (up to 8.0 mg/L). Bacteriology results showed higher CFU counts for CYT in the CON tanks from 8 to 24 dph, and at 24 dph counts were higher in SCT. CFU counts were higher for WSB in the CON tank at 9 and 13 dph but otherwise there were no differences over time. Perhaps most notable was that the SCT tanks yielded a fourfold reduction in labor when compared to CON tanks due to more efficient siphoning.

Recent advances in in-vitro meat production – a review

Abstract In-vitro meat production has entered into the phase of pilot-commercial scale production from the conceptual-laboratory phase. The main challenge for in-vitro meat production on a commercial scale is the very high cost of its production, mainly due to the cost of cell culture media, growth regulators, and the requirement of highly skilled manpower. The development of serum-free and animal-free culture media with plant, microbial, and fungi-derived compounds through recombinant technology and media recycling is crucial for scaling up in-vitro meat production and reducing the price of the end products. The proper design of bioreactors specific to in-vitro meat production, their automation, utilization of natural and edible scaffolds, and microcarriers made up of edible materials are the present focus of researchers. The co-culturing by proliferating various cells such as adipocytes, chondrocytes, fibroblasts, and endothelial cells are applied for imparting textural and organoleptic attributes to developed products similar to conventional meat. The industrial process to produce in-vitro meat needs a clear synergy between the biological, chemical, technical, and industrial fields because at the moment the main research focus is on the development and improvement of cell lines available to set up cell culture and culture media, bioreactors, cell lines, scaffolding, and biofabrication. The research on in-vitro meat is limited by the fact that from the industry the protocols are not properly divulgated.

Microplastic Abundance in the Locally Produced Commercial Compost and the Characteristics

Compost is a widely used soil amendment in the agricultural sector in Sri Lanka. Applying compost could improve soil quality, and it is used in reclaiming degraded agricultural lands. However, low grade compost that contains pollutants may have adverse effects on the quality of the agro-ecosystem. Microplastic is a possible contaminant that can be moved into the agro-ecosystem through poor quality compost application. The present study was conducted to assess the microplastic availability and characteristics of locally produced municipal solid waste and agricultural waste compost. Representing commercial scale agricultural and municipal solid waste composting facilities; twenty compost samples with three replicates were obtained for microplastic identification. A combination of methods (manual separation, oxidation digestion plus density separation) was used to separate and detect microplastics from compost samples. This study revealed that; microplastics are present in agricultural and municipal solid waste compost. Municipal solid waste compost contained significantly (p<0.05) higher microplastic than agricultural waste compost (on average 0.63% and 0.033%, respectively). Average amount of soft plastic content in municipal solid waste compost and agricultural waste compost (1321 items/kg and 71 items/kg, respectively) were higher than the hard plastics (388 items/kg and 37 items/kg, respectively). The study confirmed that compost could act as a carrier of microplastics in agricultural ecosystems. It can be recommended that quality standards should be implemented to minimize the microplastic content in compost and the code of practices for municipal solid waste compost production should be updated to control microplastic contamination to safeguard the quality of agro-ecosystems.

Eco-Friendly Synthesis Methods of Gold Nanoparticles, Their Characterization and Applications in Diagnostic, Therapeutic and Sensors

Nanoparticles have unique traits which make them useful for different purposes. Numerous methods are used to manufacture nanoparticles at commercial scale. Gold nanoparticles (AuNPs) are one of the most utilized and preferred nanoparticles due to their traits like low resistivity, less toxicity, optical, high stability, fluorescence quenching ability, and "surface plasmon resonance". Gold nanoparticles were utilized in ancient Roman Times for staining glasses and till now their new applications are being discovered every day. Various methodologies are utilized for Gold nanoparticle synthesis including conventional chemical methods, UV rays, polymers, ultrasound, plant and microbe-mediated techniques, etc. Conventional techniques are not eco-friendly or cost-effective. Nowadays plants and microbes being cost-effective and eco-friendly are preferred for gold nanoparticle synthesis. Various extracellular, intracellular, and biomolecular techniques are being utilized to manufacture gold nanoparticles. Gold nanoparticles have a vast scope in chemical, biomedicine, food, electronic and forensic industries. AuNPs are widely utilized as sensors, also as carriers in Drug delivery, Photothermal therapy, Heavy metal ion detection etc. This review describes various synthesis techniques, applications, and characterizations of AuNPs.

Physico-Chemical and Microbiological Changes in Degradation of Agri-residue under Pit Compositing

Management of crop residues has remained a major challenge due to lack of easily adaptable and affordable interventions at farmer’s field. Cellulolytic bacteria and fungi have been recommended for recycling lignocellulosic-rich organic matter and to convert it into nutrient rich compost. However, these inoculants need to be generated on commercial scale for handling large volume of biomass. Also, the microbial formulation should also be capable of degrading diverse type of agri-residues. Seven fungal strains, namely Aspergillus awamori (F-18), Aspergillus nidulans, Trichoderma viride, Trichoderma longibrachitum, Drechslerahalodes, Eupenicilliumcrustaceumand Paecilomycesvariotiiwere characterized based on shelf life, functional activity to make consortium for degradation of various agro and horticultural residues using pit method of composting. An experiment was laid in cemented pits using four different substrates-maize cobs and stalks, paddy straw, kinnow fruit waste and flower waste for rapid degradation. The results revealed a maximum increase in spore count with Paecilomycesvariotii followed by Eupenicilliumcrustaceum and Drechslerahalodes. Out of four different additives, glycerol was found to be most suitable additive for incubation of selected fungi. The results on microbial population revealed highest bacterial population in flower waste and highest actinobacterial population in kinnow waste. It was also observed that inoculated organic waste degraded faster than un-inoculated wastes. As the degradation process progressed, total N also increased with time and varied from 1.1 to 1.5 percent. Flower and kinnow waste degradation was completed in 45 days while that of maize and paddy straw in 75 and 90 days, respectively. The pH range was 6.5-8.0 in all the substrates but in inoculated substrates, the range of pH was 7.2-7.6, while electrical conductivity (EC) was 1.4-3.6. The highest humus% was found with paddy straw followed by maize, flower and kinnow. The final product also showed variation in K% and S% which were found to be 0.6% -1.8% and 0.1% -0.20%, respectively.

Influence of rice straw and wood fiber combination on physical and mechanical properties of rice straw pulverized composite board

The production of particleboards from various kinds of ligno cellulosic materials are successful on commercial scale in various parts of the country. However, much success is not seen in use of crop residues for particleboards. Rice straw and wheat straw are one such materials that are abundantly available in India that can be used to produce particleboard. The present work investigated the effect of Rice straw particles and wood fibers combination on physical and mechanical properties of the composite board. The pulverized rice straw composite boards were produced with three different composition of rice straw material (100 %, 70 %, 50 %) and wood Fibers (0 %, 30 %, 50 %). Melamine Urea Formaldehyde (MUF), Phenol Cardanol Formaldehyde (PCF), Blocked Isocyanate resin combined with PCF (BPCF), Blocked Isocyanate combined with Urea Melamine Formaldehyde (BUMF) and Blocked Isocyanate combined with PF (BPF) resins were synthesized. The resin system (10%,12%,14%) with requisite additive was admixed with rice straw and wood fibers. According to the resin system employed, the hot press temperature, specific pressure and curing time were worked out for compression of the boards. The boards were produced with 780 - 850 kg/m3 nominal density and prior to testing, the test specimens were exposed to an atmosphere maintained at a relative humidity of 65 ± 5 percent and at a temperature of 27 ± 2 °C until their masses are nearly constant. The boards made were subjected for evaluation of physical and mechanical properties according to IS 3087. It was found that the Rice Straw particles with Wood Fibers of 50-50 combination bonded with PCF and also with MUF adhesive of 12 % resin solids confirms to the requirement of physical and mechanical properties as per IS 3087 particleboards of wood and other lignocellulosic materials (medium density) for general purposes Specification. Comparison with resin for hybrid boards of rice straw particles with wood fiber, BPCF has shown excellent properties than BPF and BUMF. The study indicated that increasing the percentage replacement of wood fibers with rice straw particles by more than 50 % decreased the internal bond strength. It can be concluded that rice straw pulverized particleboard can be successfully made with the combination of 30 % - 50 % wood fibers using PCF resin or BPCF resin.

Evidence-Based Guidelines for Low-Risk Ethics Applicants: A Qualitative Analysis of the Most Frequent Feedback Made by Human Research Ethics Proposal Reviewers

Human Research Ethics Committee (HREC) reviewers often provide similar feedback across applications, which suggests that the problem lies in researcher awareness of key issues rather than novel, unsolvable challenges. If common problems can be addressed before lodgement by applicants referencing clear evidence-based supports (e.g., FAQs on common application shortcomings), it would improve efficiency for HREC members and expedite approvals. We aim to inform such supports by analysing the patterns in the most frequent feedback made by HREC members during review processes. We collected every instance (N = 4,195) of feedback made on N = 197 ‘low-risk’ protocols by all HREC staff (N = 16) at one institution over the course of a full year (2019). Reflexive thematic analysis to identify themes (and content analysis to determine relative frequency) revealed that the top three themes are consistent with existing literature: Consent, Administrative, and Methodological concerns. However, we identified important new themes that are not captured in previous research, including ‘Risk to Researchers’, ‘Commercial benefit, scope and scale’, ‘Diversity’ (covering issues of cultural sensitivity, language and accessibility), as well as fair right to a complaints process. Our thorough exploration of information-rich primary data marks an important methodological improvement over previous studies and offers a theoretical contribution to understanding themes that have heretofore been overlooked in the ethics review process. By identifying the common challenges experienced in HREC review we can better inform tailored supports to applicants (by extension reducing workload burdens on HREC systems) and reduce their perceived barriers to engaging in challenging but meaningful research.

What will it take to get to 250,000 ppm brine concentration via ultra-high pressure reverse osmosis? And is it worth it?

The possibility of ultra-high pressure reverse osmosis (UHPRO) to replace thermal brine concentration promises to reduce up to 50 % of both energy consumption and capital cost. However, commercially available reverse osmosis (RO) membranes lose up to 50 % of their water permeability when operated up to 200 bar. Higher temperature operations such as in Middle East seawater desalination and brine mining further exacerbate compaction due to softening of the polysulfone support membrane. Assuming that pressure and temperature-related compaction issues can be resolved through innovations in membrane materials and/or module designs, this study asks the questions, “What will it take to get to 250,000 ppm via ultra-high pressure reverse osmosis? And is it worth it?” Herein we comprehensively examine a three stage RO process beginning with seawater RO (SWRO) to high-pressure RO (HPRO) and ultra-high-pressure RO (UHPRO). We elucidate the influence of thermophysical properties, hydraulic pressure, permeate flux, water permeability, feed spacer design, concentration polarization (CP), salt rejection and stage design on recovery and specific energy consumption (SEC). Our analysis of high rejection (HR) and high flux (HF) RO membranes reveals that while HF RO membranes boast superior water permeability and lower trans-membrane (hydraulic) pressure (TMP), they require higher operating flux, which leads to severe CP and operating pressures of 300 to 400 bar to meet the targeted brine concentration of ~250 g/L TDS. In addition, membrane compaction drives up the TMP, SEC, and capital cost of UHPRO systems. To bring the applied pressure below 300 bar, compaction-resistant UHPRO membranes and mass-transfer enhancing feed spacers will be required. The findings herein show that it will take time, money and technological innovation to enable UHPRO at commercial scale, and it may or may not be worth it. Further, this work makes clear the technological refinements needed to enable UHPRO membrane brine concentration.

Morphological, Cultural Characteristics of Post-Harvest Diseases in Onion and its Management through Bio-Agents

The onion (Allium cepa L.) is a biennial herb characterized by its bulbous structure, and it stands as one of the vital vegetable crops cultivated in India. Its origins can be traced back to the central Asian region. This underground bulbous vegetable crop is cultivated on a commercial scale due to its extensive adaptability and the significant potential for high production. Classified under the Amaryllidaceae family and Allium genus, the onion holds a pivotal role in the world of vegetables. The primary culprits responsible for onion bulb rot after harvesting were identified as Aspergillus niger, A. flavus, and Fusarium oxysporum f. sp. cepae. It was determined that the media PDA, SDA, MEA, and YDA were conducive to the growth and sporulation of A. niger mycelium. Conversely, MEA, OM, PDA, and YDA were found to be favorable for the development and sporulation of A. flavus. Lastly, PDA, CDA, OMA, and RA culture media demonstrated suitability for promoting mycelial growth and sporulation of F. oxysporum f. sp. cepae.

Growth in turbine size and technological development of modern commercial large scale wind turbines in Türkiye

In this study, in addition to the recent advances and tendencies in wind turbine technology around the world, the progress of commercial wind turbine technology installed in Turkey was also thoroughly examined. In this respect, several metrics for installed wind turbines including number of turbines, installed power capacity (MW), mean rated capacity (MW), mean rotor diameter (m), mean specific power capacity (W/m2), and mean hub height (m) have been obtained between the years of 2011 and 2019. According to the obtained results, the mean rated capacity of Turkey’s annual installed wind turbines advanced from 1.86 MW in 2011 to 3.52 MW in 2019. However, the mean specific power of yearly installed wind turbines declined from 423.7 W/m2 to 314.1 W/m2. Outcomes revealed that the growth in the size and the reduction in the specific power have contributed to the tendency of higher power outputs, and wind turbine capacity factor and power generation capacity have been on the rise in Turkey. In time, wind turbines with greater rotor diameters and hubs started to show up more observable on land. For that purpose, the proposed solution to regulate turbine visibility during site selection is the potential visibility model (PVM), which is meant to be used as an auxiliary variable.

Comparative Analysis of Purification and Characterization Process of Phycocyanin Pigment from Spirulina Subsalsa with Arthrospira Platensis from Mexico

The Arthrospira maxima, Spirulina major, and Spirulina subsalsa are plenty available in Mexican lakes and ponds. This cyanobacterium is used as an important dietary supplement due to its high protein content and vitamins. However, the most commercial strain in use is A. platensis, and very few reports exist on other Spirulina species from Mexico and their potential phycocyanin production. To use at a commercial scale, it is essential to evaluate native strains in an efficient purification process. In this work, we demonstrated the potential of Spirulina subsalsa for phycocyanin pigment production and purification process, compared with native A. platensis from Mexico. The biomass yield with S. subsalsa was 4.50±0.10 g/Lt, which was higher than A. platensis, which was 1.36 g/lt. The crude phycocyanin pigment from S. subsalsa was 267±0.37 mg/g, whereas 221±0.04mg/g in the case of A. platensis. After partial purification, we found a higher purity grade in S. subsalsa, with a higher yield and a recovery percent of 39.75%. In the case of A. platensis, after partial purification, the recovery percentage was 35.37. After ionic chromatography purification, the purity of phycocyanin was 2.57±0.03 in the case of S. subsalsa, whereas 1.91±0.02 in the case of A. platensis. SDS gel electrophoresis demonstrated two phycocyanin bands showing 17 kDa and 12 kDa in the case of both species. The two-step purification process functions very well for S. subsalsa species, whereas A. platensis demonstrated efficiency with one step. The extracted C-PC from S. Sulsalsa is safe as per the cytotoxicity assay.

Evaluating the Environmental Sustainability of Alternative Ways to Produce Benzene, Toluene, and Xylene.

The petrochemical industry can reduce its environmental impacts by moving from fossil resources to alternative carbon feedstocks. Biomass and plastic waste-based production pathways have recently been developed for benzene, toluene, and xylene (BTX). This study evaluates the environmental impacts of these novel BTX pathways at a commercial and future (2050) scale, combining traditional life cycle assessment with absolute environmental sustainability assessment using the planetary boundary concept. We show that plastic waste-based BTX has lower environmental impacts than fossil BTX, including a 12% decrease in greenhouse gas (GHG) emissions. Biomass-based BTX shows greater GHG emission reductions (42%), but it causes increased freshwater consumption and eutrophication. Toward 2050, GHG emission reductions become 75 and 107% for plastic waste and biobased production, respectively, compared to current fossil-BTX production. When comparing alternative uses of plastic waste, BTX production has larger climate benefits than waste incineration with energy recovery with a GHG benefit of 1.1 kg CO2-equiv/kg plastic waste. For biomass (glycerol)-based BTX production, other uses of glycerol are favorable over BTX production. While alternative BTX production pathways can decrease environmental impacts, they still transgress multiple planetary boundaries. Further impact reduction efforts are thus required, such as using other types of (waste) biomass, increasing carbon recycling, and abatement of end-of-life emissions.

Life cycle assessment of citrus tree nurseries in Uruguay: Are their environmental impacts relevant?

Perennial fruit production at the commercial scale, such as citrus fruits, begins with seedling production in a nursery. This stage lasts several months and involves different phases and the use of substrates and infrastructure. As the seedling does not produce fruit but does consume inputs, studying the environmental impacts associated with this stage becomes relevant, especially to understand its contribution to the total impact of the crop cycle. Despite the global relevance of fruit tree seedlings production, LCA studies in the literature focus on horticultural crop nurseries, and those on perennial tree nurseries do not consider both substrate and structures in the analysis, which is key for this type of crop since the main production system is soilless production in greenhouses. Thus, the main goal of this study is to quantify the environmental impacts related to the production of citrus fruit tree seedlings using LCA, analyse the main production system applied nowadays, and study its relevance with respect to the crop cycle. To this end, a certified Uruguayan citrus nursery was analysed, from which primary data was obtained. As well, methodological issues concerning water consumption and modelling emissions from input applications in soilless greenhouse systems are tackled. Results show that the main hotspots of the nursery stage are infrastructure production and peat transportation, which highlights the relevance of their inclusion when modelling the system. Extending the lifespan of the galvanised steel structures and decreasing substrate transport distances are shown to be effective measures to reduce environmental impacts. The contribution of the nursery stage to the citrus production cycle is negligible for almost all the impact categories assessed except cancer human toxicity, as it accounts for 0–3.6% of the impacts depending on the impact category. Great differences (from 10 to 400 times higher results on average) are observed when comparing the results with those from commercial databases, as they consider open-field nurseries where seedlings are grown in the soil. The need to develop harmonised methods to model water consumption and fertiliser and pesticide emissions for soilless crops in greenhouses arises. The present study presents a complete quantification of the environmental impacts of the main production system of citrus fruit tree seedlings and provides scientific and quantitative evidence of its contribution to the production cycle, helping decision-makers understand where efforts should be focused to achieve a more sustainable fruticulture.

Impact of DNI Forecast Quality on Performance Prediction for a Commercial Scale Solar Tower

Concerning current efforts to improve operational efficiency and to lower overall costs of concentrating solar power (CSP) plants with prediction-based algorithms, this study investigates the quality and uncertainty of nowcasting data regarding the implications for process predictions. DNI (direct normal irradiation) maps from an all-sky imager-based nowcasting system are applied to a dynamic prediction model coupled with ray tracing. The results underline the need for high-resolution DNI maps in order to predict net yield and receiver outlet temperature realistically. Furthermore, based on a statistical uncertainty analysis, a correlation is developed, which allows for predicting the uncertainty of the net power prediction based on the corresponding DNI forecast uncertainty. However, the study reveals significant prediction errors and the demand for further improvement in the accuracy at which local shadings are forecasted.

Bottom-up production of injectable itraconazole suspensions using membrane technology

Bottom-up production of active pharmaceutical ingredient (API) crystal suspensions offers advantages in surface property control and operational ease over top-down methods. However, downstream separation and concentration pose challenges. This proof-of-concept study explores membrane diafiltration as a comprehensive solution for downstream processing of API crystal suspensions produced via anti-solvent crystallization. It involves switching the residual solvent (N-methyl-2-pyrrolidone, NMP) with water, adjusting the excipient (d-α-Tocopherol polyethylene glycol 1000 succinate, TPGS) quantity, and enhancing API loading (solid concentration) in itraconazole crystal suspensions. NMP concentration was decreased from 9 wt% to below 0.05 wt% (in compliance with European Medicine Agency guidelines), while the TPGS concentration was decreased from 0.475 wt% to 0.07 wt%. This reduced the TPGS-to-itraconazole ratio from 1:2 to less than 1:50 and raised the itraconazole loading from 1 wt% to 35.6 wt%. Importantly, these changes did not adversely affect the itraconazole crystal stability in suspension. This study presents membrane diafiltration as a one-step solution to address downstream challenges in bottom-up API crystal suspension production. These findings contribute to optimizing pharmaceutical manufacturing processes and hold promise for advancing the development of long-acting API crystal suspensions via bottom-up production techniques at a commercial scale.

Valorisation of Sugarcane Bagasse for the Sustainable Production of Polyhydroxyalkanoates

With the world shifting towards renewable and sustainable resources, polyhydroxyalkanoates (PHAs) have attracted significant interest as an alternative to synthetic plastics. While possessing promising properties suitable for various applications, the production of PHAs has not yet reached a global commercial scale. The main reason is the high cost of production, which represents a major limitation. Sugarcane bagasse (SCB) is an abundant lignocellulosic waste around the world. Its use to produce PHA enhances the feasibility of producing PHAs at commercial scale. However, SCB requires pretreatment and hydrolysis steps to release the sugars prior to the microbial fermentation. The cost associated with these steps poses additional challenges for large-scale production. Another challenge is the release of inhibitors during the pretreatment process which can result in a low PHA yield. The development of a low cost, co-culture strategy for the bioconversion of SCB into PHAs, can represent a pivotal step towards the large-scale production of bioplastics. This review highlights the advancements made in recent years on the microbial production of PHA using SCB as potential feedstock, with a proposed biological strategy and circular economy model.

Optimization of scrap tire devulcanization process using Taguchi and DEAR method in a supercritical fluid extraction pilot scale setup

Recycling of scrap tires is gaining more significance to ensure sustainable consumption and production on a commercial scale. The supercritical CO2 extraction technique has been classified as green technology under United Nation's sustainable development guidelines. Literature shows that research on scrap tire devulcanization using supercritical CO2 was performed on a laboratory-scale setup only. However, significant pilot-scale research needs to be conducted before commercial use and technology transfer. This study utilized a pilot-scale supercritical fluid extraction equipment to devulcanize waste tire-derived crumb rubber. Using Taguchi's design of experiment (DOE) model along with the Data Envelopment Analysis Based Ranking (DEAR) approach, the effect of the input process variables on response factors was examined. The input functions, devulcanizing agent's concentration, and pump pressure were discovered to be the most influential parameters in the devulcanization process. Further optimization was carried out via the DEAR-Taguchi technique. The optimal process parameters were determined to be a pump pressure of 350 bar, an extractor temperature of 80 °C, a holding time of 30 min in the extractor, a CO2 circulation of 120 min, and a devulcanizing agent concentration of 15 vol.%. Finally, a validation experiment was conducted at the optimum conditions to verify the acceptability of the model. It was noticed that the divergence for the confirmation experiment was within 10 %, indicating that the approach used for the devulcanization of crumb rubber is acceptable.

RNA-seq analysis reveals narrow differential gene expression in MEP and MVA pathways responsible for phytochemical divergence in extreme genotypes of Thymus daenensis Celak

BackgroundHere, we investigated the underlying transcriptional-level evidence behind phytochemical differences between two metabolically extreme genotypes of Thymus daenensis. The genotypes ‘Zagheh-11’ (thymol/carvacrol type, poor in essential oil [EO] [2.9%] but rich in triterpenic acids) and ‘Malayer-21’ (thymol type and rich in EO [3.8%]) were selected from an ongoing breeding program and then clonally propagated for further experimental use.Materials and methodsGC-MS, GC-FID, and HPLC-PDA were utilized to monitor the fluctuation of secondary metabolites at four phenological stages (vegetative, bud burst, early, and full-flowering stages). The highest phytochemical divergence was observed at early flowering stage. Both genotypes were subjected to mRNA sequencing (approximately 100 million paired reads) at the aforementioned stage. The expression patterns of four key genes involved in the biosynthesis of terpenoids were also validated using qRT-PCR.ResultsCarvacrol content in ‘Zagheh-11’ (26.13%) was approximately 23 times higher than ‘Malayer-21’ (1.12%). Reciprocally, about 10% higher thymol was found in ‘Malayer-21’ (62.15%). Moreover, the concentrations of three major triterpenic acids in ‘Zagheh-11’ were approximately as twice as those found in ‘Malayer-21’. Transcriptome analysis revealed a total of 1840 unigenes that were differentially expressed, including terpene synthases, cytochrome P450, and terpenoid backbone genes. Several differentially expressed transcription factors (such as MYB, bZIP, HB-HD-ZIP, and WRKY families) were also identified. These results suggest that an active cytosolic mevalonate (MVA) pathway may be linked to higher levels of sesquiterpenes, triterpenic acids, and carvacrol in ‘Zagheh-11’. The chloroplastic pathway of methyl erythritol phosphate (MEP) may have also contributed to a higher accumulation of thymol in Malayer-21. Indeed, ‘Zagheh-11’ showed higher expression of certain genes (HMGR, CYP71D180, β-amyrin 28-monooxygenase, and sesquiterpene synthases) in the MVA pathway, while some genes in the MEP pathway (including DXR, ispG, and γ-terpinene synthase) were distinctly expressed in Malayer-21. Future efforts in metabolic engineering of MVA/MEP pathways may benefit from these findings to produce increased levels of desired secondary metabolites at commercial scale.