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High pressure represents extreme environments and provides opportunities for materials discovery1-8. Thermal transport under high hydrostatic pressure has been investigated for more than 100 years and all measurements of crystals so far have indicated a monotonically increasing lattice thermal conductivity. Here we report in situ thermal transport measurements in the newly discovered semiconductor crystal boron arsenide, and observe an anomalous pressure dependence of the thermal conductivity. We use ultrafast optics, Raman spectroscopy and inelastic X-ray scattering measurements to examine the phonon bandstructure evolution of the optical and acoustic branches, as well as thermal conductivity under varied temperatures and pressures up to 32 gigapascals. Using atomistic theory, we attribute the anomalous high-pressure behaviour to competitive heat conduction channels from interactive high-order anharmonicity physics inherent to the unique phonon bandstructure. Our study verifies ab initio theory calculations and we show that the phonon dynamics-resulting from competing three-phonon and four-phonon scattering processes-are beyond those expected from classical models and seen in common materials. This work uses high-pressure spectroscopy combined with atomistic theory as a powerful approach to probe complex phonon physics and provide fundamental insights for understanding microscopic energy transport in materials of extreme properties.
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Dependency on plastic commodities has led to a recurrent increase in their global production every year. Conventionally, plastic products are derived from fossil fuels, leading to severe environmental concerns. The recent coronavirus disease 2019 pandemic has triggered an increase in medical waste. Conversely, it has disrupted the supply chain of personal protective equipment (PPE). Valorisation of food waste was performed to cultivate C. necator for fermentative production of biopolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). The increase in biomass, PHBV yield and molar 3-hydroxy valerate (3HV) content was estimated after feeding volatile fatty acids. The fed-batch fermentation strategy reported in this study produced 15.65 ± 0.14 g/L of biomass with 5.32 g/L of PHBV with 50% molar 3HV content. This is a crucial finding, as molar concentration of 3HV can be modulated to suit the specification of biopolymer (film or fabric). The strategy applied in this study addresses the issue of global food waste burden and subsequently generates biopolymer PHBV, turning waste to wealth.
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COVID-19 , Cupriavidus necator , Residuos Sanitarios , Eliminación de Residuos , Biopolímeros , Cupriavidus necator/metabolismo , Fermentación , Alimentos , Combustibles Fósiles , Humanos , Hidroxibutiratos , Ácidos Pentanoicos , Plásticos , Poliésteres , ValeratosRESUMEN
The immune system is integral to the surveillance and eradication of tumor cells. Interactions between the natural killer group 2 member D (NKG2D) receptor and its ligands (NKG2DLs) are vital for activating NKG2D receptorpositive immune cells, such as natural killer cells. This activation enables these cells to identify and destroy tumor cells presenting with NKG2DLs, which is an essential aspect of tumor immunity. However, tumor immune escape is facilitated by soluble NKG2DL (sNKG2DL) shed from the surface of tumor cells. The production of sNKG2DL is predominantly regulated by metalloproteinases [a disintegrin and metalloproteinases (ADAM) and matrix metalloproteinase (MMP) families] and exosomes. sNKG2DL not only diminish immune recognition on the tumor cell surface but also suppress the function of immune cells, such as NK cells, and reduce the expression of the NKG2D receptor. This process promotes immune evasion, progression, and metastasis of tumors. In this review, an indepth summary of the mechanisms and factors that influence sNKG2DL production and their contribution to immune suppression within the tumor microenvironment are provided. Furthermore, due to the significant link between sNKG2DLs and tumor progression and metastasis, they have great potential as novel biomarkers. Detectable via liquid biopsies, sNKG2DLs could assess tumor malignancy and prognosis, and act as pivotal targets for immunotherapy. This could lead to the discovery of new drugs or the enhancement of existing treatments. Thus, the application of sNKG2DLs in clinical oncology was explored, offering substantial theoretical support for the development of innovative immunotherapeutic strategies for sNKG2DLs.
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Células Asesinas Naturales , Subfamilia K de Receptores Similares a Lectina de Células NK , Neoplasias , Escape del Tumor , Microambiente Tumoral , Humanos , Neoplasias/inmunología , Neoplasias/patología , Subfamilia K de Receptores Similares a Lectina de Células NK/metabolismo , Células Asesinas Naturales/inmunología , Microambiente Tumoral/inmunología , Ligandos , Proteínas Ligadas a GPI/inmunología , Proteínas Ligadas a GPI/metabolismo , Péptidos y Proteínas de Señalización IntercelularRESUMEN
This study focused on the development of cross-linked poly(ester urethane)/starch (PEUST) composites containing 50 wt% starch content for food-packaging materials. The NCO-terminated poly(caprolactone-urethane) prepolymer (PCUP) was first synthesized through bulk condensation. Then, low-moisture starch (0.21 wt%) and PCUP-based PEUST films were fabricated through an intensive extrusion process, followed by thermo-compression molding. The chemical structure of PCUP and PEUST was confirmed using Fourier transform infrared spectroscopy. Moreover, a comprehensive evaluation was conducted to assess the influence of cross-link density on the physicochemical properties of the composite films. The results showed that an increase in the cross-link density within the composites improved component compatibility and tensile strength but reduced crystallinity, water sensitivity, hydrolytic degradability, and water vapor permeability (WVP) of the films. In addition, the cytotoxicity tests were conducted to evaluate the safety of the composite films, and the high cell viability demonstrated non-toxicity for food application. The PEUST-II films with moderate cross-link density exhibited a suitable degradation rate (27.7 % weight loss at degradation for 140 d), optimal tensile properties (tensile strength at break: 12.4 MPa; elongation at break: 352 %), and low WVP (68.4 g/(m2â 24h) at 30 % relative humidity). These characteristics make them highly promising as fresh-keeping food packaging.
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Embalaje de Alimentos , Poliésteres , Almidón , Almidón/química , Ésteres , Poliuretanos/química , PermeabilidadRESUMEN
This communication explores the intricate relationship between food waste and climate change, considering aspects such as impacts, projections, and emissions. It focuses on the pressing issue of waste generation and its potential consequences if current trends persist, and emphasises the importance of efficient solid waste management in improving environmental quality and fostering economic development. It also highlights the challenges faced by developing countries in waste collection and disposal, drawing comparisons with the waste utilisation methods used by developed nations. The review delves into the link between food waste and climate change, noting the paradoxical situation of food wastage against the backdrop of global hunger and malnutrition. It underscores the scientific evidence connecting food waste to climate change and its implications for food security and climate systems. Additionally, it examines the environmental burden imposed by food waste, including its contribution to greenhouse gas emissions and the depletion of resources such as energy, water, and land. Besides environmental concerns, this communication also highlights the ethical and socioeconomic dimensions of food waste, discussing its influence on Sustainable Development Goals, poverty, and social inequality. The communication concludes by advocating for collective action and the development of successful mitigation strategies, technological solutions, and policy interventions to address food waste and its climate impacts. It emphasises the need for collaboration, awareness, and informed decision-making to ensure a more sustainable and equitable future.
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Cambio Climático , Eliminación de Residuos , Alimentos , Alimento Perdido y Desperdiciado , Uniones ComunicantesRESUMEN
Plastics are indispensable in modern society but also pose a persistent threat to the environment. In particular, microplastics (MPs) have a substantial environmental impact on ecosystems. Municipal solid waste landfill leachates are a source of MPs, but leakage of MPs from leachates has only been reported in a few studies. As a modern city, Hong Kong has a remarkably high population density and a massive plastic waste generation. However, it depends on conventional landfilling for plastic waste management and traditional thermal ammonia stripping for leachate treatment. Yet, the MP leakage from landfill leachates in Hong Kong has not been disclosed. This is the first study that aimed to identify, quantify, and characterise MPs in raw and treated leachates, respectively, from major landfill sites in Hong Kong. The concentrations of MPs varied from 49.0 ± 24.3 to 507.6 ± 37.3 items/L among the raw leachate samples, and a potential correlation was found between the concentration of MPs in the raw leachate sample from a given landfill site and the annual leachate generation of the site. Most MPs were 100-500 µm fragments or filaments and were transparent or yellow. Regarding the polymeric materials among the identified MPs, poly(ethylene terephthalate) and polyethylene were the most abundant types, comprising 45.30% and 21.37% of MPs, respectively. Interestingly, leachates treated by ammonia stripping contained higher concentrations of MPs than raw leachate samples, which demonstrated that the traditional treatment process may not be sufficient regarding the removal of emerging pollutants, such as MPs. Overall, our findings provide a more comprehensive picture of the pollution of MPs in landfill leachates in Hong Kong and highlight the urgent need for adopting the consideration of MPs into the conventional mindset of waste management systems in Hong Kong.
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Eliminación de Residuos , Contaminantes Químicos del Agua , Residuos Sólidos/análisis , Microplásticos , Plásticos , Contaminantes Químicos del Agua/análisis , Hong Kong , Amoníaco , Ecosistema , Instalaciones de Eliminación de Residuos , ChinaRESUMEN
Twisted van der Waals materials featuring Moiré patterns present new design possibilities and demonstrate unconventional behaviors in electrical, optical, spintronic, and superconducting properties. However, experimental exploration of thermal transport across Moiré patterns has not been as extensive, despite its critical role in nanoelectronics, thermal management, and energy technologies. Here, the first experimental study is conducted on thermal transport across twisted graphene, demonstrating a phonon polarizer concept from the rotational misalignment between stacked layers. The direct thermal and acoustic measurements, structural characterizations, and atomistic modeling, reveal a modulation up to 631% in thermal conductance with various Moiré angles, while maintaining a high acoustic transmission. By comparing experiments with density functional theory and molecular dynamics simulations, mode-dependent phonon transmissions are quantified based on the angle alignment of graphene band structures and attributed to the coupling among flexural phonon modes. The agreement confirms the dominant tuning mechanisms in adjusting phonon transmission from high-frequency thermal modes while having negligible effects on low-frequency acoustic modes near Brillouin zone center. This study offers crucial insights into the fundamental thermal transport in Moiré structures, opening avenues for the invention of quantum thermal devices and new design methodologies based on manipulations of vibrational band structures and phonon spectra.
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BACKGROUND: Myopia is a serious public health issue. High school-aged adolescents in Beijing have an alarming prevalence of myopia. Therefore, determining myopia protective factors is essential. Green space has a certain association with myopia protective factors that can protect against myopia. OBJECTIVE: This study aims to examine the effects of green space around schools on individual myopia risk in high school-aged adolescents and the school-level myopia prevalence. METHODS: Green space was measured using the normalized difference vegetation index (NDVI). A total of 13,380 samples of 51 high schools were selected from a 2021 Beijing Municipal Health Commission survey. Adolescent myopia was defined as a spherical equivalent of ≤-1.00 diopters in the worse eye. Generalized linear mixed models with a binomial error structure were used to analyze the effects of the NDVI on personal myopia risk and adjust them by other factors, such as demographics, exposure time, and outdoor exercise. The effects of the NDVI on school-level myopia prevalence with adjusted demographics and the relative position factors of trees were analyzed through quasibinomial regression. RESULTS: The overall prevalence of myopia was 80.61% (10,785/13,380, 95% CI 79.93%-81.27%). Although with a 0.1 increase in the 500 and 1000 m buffer NDVIs adjusted by demographic and other factors, the high school-aged personal myopia risk significantly dropped by 16% (odds ratio [OR] 0.84, 95% CI 0.73-0.97) and 12% (OR 0.88, 95% CI 0.79-0.99), respectively. However, only the adjusted 500 m buffer NDVI (by demographics and the position of trees) with a 0.1 increase significantly reduced the school-level myopia prevalence by 15% (OR 0.85, 95% CI 0.74-0.98). Subgroup analysis showed that the adjusted effects of the 500 m buffer NDVI are significant in schoolgirls (OR 0.82, 95% CI 0.72-0.93), juniors (OR 0.82, 95% CI 0.72-0.94), the Han nationality (OR 0.84, 95% CI 0.72-0.97), 1-year exposure (OR 0.84, 95% CI 0.71-0.99) and 3-year exposure (OR 0.78, 95% CI 0.65-0.94). CONCLUSIONS: The greenness of a 500 m buffer around schools is associated with a lower personal myopia risk among adolescents and a lower prevalence of myopia in schools. With regard to prevention and control activities, green space within a 500 m buffer around schools is suggested as an independent protective factor for adolescent myopia.
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Miopía , Humanos , Adolescente , Niño , Estudios Transversales , Prevalencia , Miopía/epidemiología , Refracción Ocular , Instituciones AcadémicasRESUMEN
In general, vibrational physics has been well described by quantum perturbation theory to provide footprint characteristics for common crystals. However, despite weak phonon anharmonicity, the recently discovered cubic crystals have shown anomalous vibrational dynamics with elusive fundamental origin. Here, we developed a non-perturbative ab initio approach, in together with spectroscopy and high-pressure experiments, to successfully determine the exact dynamic evolutions of the vibrational physics for the first time. We found that the local fluctuation and coupling isotopes significantly dictate the vibrational spectra, through the Brillouin zone folding that has been previously ignored in literature. By decomposing vibrational spectra into individual isotope eigenvectors, we observed both positive and negative contributions to Raman intensity from constitutional atoms (10B, 11B, 75As or 31P). Importantly, our non-perturbative theory predicts that a novel vibrational resonance appears at high hydrostatic pressure due to broken translational symmetry, which was indeed verified by experimental measurement under a pressure up to 31.5 GPa. Our study develops fundamental understandings for the anomalous lattice physics under the failure of quantum perturbation theory and provides a new approach in exploring novel transport phenomena for materials of extreme properties.
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Controlling heat flow is a key challenge for applications ranging from thermal management in electronics to energy systems, industrial processing, and thermal therapy. However, progress has generally been limited by slow response times and low tunability in thermal conductance. In this work, we demonstrate an electronically gated solid-state thermal switch using self-assembled molecular junctions to achieve excellent performance at room temperature. In this three-terminal device, heat flow is continuously and reversibly modulated by an electric field through carefully controlled chemical bonding and charge distributions within the molecular interface. The devices have ultrahigh switching speeds above 1 megahertz, have on/off ratios in thermal conductance greater than 1300%, and can be switched more than 1 million times. We anticipate that these advances will generate opportunities in molecular engineering for thermal management systems and thermal circuit design.
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Extracellular protein disulfide isomerases (PDIs), including PDI, endoplasmic reticulum protein 57 (ERp57), ERp72, ERp46, and ERp5, are required for in vivo thrombus formation in mice. Platelets secrete PDIs upon activation, which regulate platelet aggregation. However, platelets secrete only â¼10% of their PDI content extracellularly. The intracellular role of PDIs in platelet function is unknown. Here, we aim to characterize the role of ERp5 (gene Pdia6) using platelet conditional knockout mice, platelet factor 4 (Pf4) Cre+/ERp5floxed (fl)/fl. Pf4Cre+/ERp5fl/fl mice developed mild macrothrombocytopenia. Platelets deficient in ERp5 showed marked dysregulation of their ER, indicated by a twofold upregulation of ER proteins, including PDI, ERp57, ERp72, ERp46, 78 kilodalton glucose-regulated protein (GRP78), and calreticulin. ERp5-deficient platelets showed an enhanced ER stress response to ex vivo and in vivo ER stress inducers, with enhanced phosphorylation of eukaryotic translation initiation factor 2A and inositol-requiring enzyme 1 (IRE1). ERp5 deficiency was associated with increased secretion of PDIs, an enhanced response to thromboxane A2 receptor activation, and increased thrombus formation in vivo. Our results support that ERp5 acts as a negative regulator of ER stress responses in platelets and highlight the importance of a disulfide isomerase in platelet ER homeostasis. The results also indicate a previously unanticipated role of platelet ER stress in platelet secretion and thrombosis. This may have important implications for the therapeutic applications of ER stress inhibitors in thrombosis.
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Plaquetas , Trombosis , Animales , Ratones , Plaquetas/metabolismo , Agregación Plaquetaria , Proteína Disulfuro Isomerasas/genética , Proteína Disulfuro Isomerasas/metabolismo , Hemostasis , Trombosis/metabolismoRESUMEN
Purpose: This randomized controlled trial aimed to evaluate the clinical efficacy of Jianyao Migu granules (JYMGG) in the treatment of primary osteopenic low back pain (LBP). Patients and Methods: A total of 108 patients with primary osteopenic LBP were randomly divided into the JYMGG group and placebo group. Both groups took 600 mg of oral Caltrate D daily; in addition, the JYMGG group was given oral JYMGG, while the placebo group was given placebo granules. The treatment period was 6 months for both groups. The pre- to post-treatment changes in the bone mineral density (BMD), visual analogue scale (VAS) score, Oswestry disability index (ODI), and bone turnover markers were compared between the two groups. Results: The post-treatment VAS score and ODI were significantly lower than baseline in both groups (P<0.05). In the JYMGG group, the lumbar BMD increased from 0.88±0.07 g/cm2 to 0.90±0.13 g/cm2 and the hip BMD increased from 0.77±0.08 g/cm2 to 0.78±0.10 g/cm2, giving increases of 2.70% and 1.96% respectively, but the differences were not statistically significant. The post-treatment levels of ALP, osteocalcin, P1NP, and ß-CTX were increased compared with baseline in both groups, but the differences were not statistically significant. The thyrotropin level was significantly increased after treatment in the placebo group (P<0.05). There were no abnormalities detected in routine blood and kidney function tests performed during the observation period. Some patients showed elevated liver enzymes and gastrointestinal reactions. Conclusion: JYMGG effectively relieved the bone pain, and improved the quality of life of patients with primary osteopenic LBP.
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Phaeodactylum tricornutum, a model alga, is well known for its ability to accumulate intracellular omega-3 eicosapentaenoic acid (EPA). However, P.tricornutum cells need to have a higher EPA content if they are to be used for industrial applications. In this study, an auxin-like supermolecule (SM) was synthesised and used for the cultivation of P. tricornutum. Results show that the addition of 1 ppm of SM significantly increased the P. tricornutum cell density and boosted the P. tricornutum biomass. The experimental group treated with 5 ppm of SM, had an EPA content of 31.7%, which was a 2.09-fold increase over the EPA content in the untreated group. Overall, our results demonstrated that SM can significantly improve the microalgal growth and EPA accumulation in P. tricornutum, providing a feasible strategy to achieve efficient and cost-effective EPA production.
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Diatomeas , Microalgas , Biomasa , Ácido Eicosapentaenoico , Ácidos IndolacéticosRESUMEN
The unicellular freshwater green alga Haematococcus pluvialis has attracted much research attention due to its biosynthetic ability for large amounts of astaxanthin, a blood-red ketocarotenoid that is used in cosmetics, nutraceuticals, and pharmaceuticals. Recently, numerous studies have investigated the functions of natural astaxanthin; however, the high cost of the production of astaxanthin from H. pluvialis cultures restricts its commercial viability. There is an urgent need to fulfill commercial demands by increasing astaxanthin accumulation from H. pluvialis cultures. In this study, we discovered that treatment of H. pluvialis cultures at the beginning of the macrozooid stage (day 0) with 1 µM rac-GR24, a synthetic analogue of strigolactones (a class of phytohormones), led to significant increases in biomass [up to a maximum dry cell weight (DCW) of 0.53 g/L] during the macrozooid stage and astaxanthin (from 0.63 to 5.32% of DCW) during the hematocyst stage. We elucidated that this enhancement of biomass accumulation during the macrozooid stage by rac-GR24 is due to its increasing CO2 utilization efficiency in photosynthesis and carbohydrate biosynthesis. We also found that rac-GR24 stimulated the overproduction of nicotinamide adenine dinucleotide phosphate (NADPH) and antioxidant enzymes in H. pluvialis cultures, which alleviated the oxidative damage caused by reactive oxygen species generated during the hematocyst stage due to the exhaustion of nitrogen supplies. Moreover, rac-GR24 treatment of H. pluvialis synergistically altered the activity of the pathways of fatty acid biosynthesis and astaxanthin esterification, which resulted in larger amounts of astaxanthin being generated by rac-GR24-treated cultures than by controls. In summary, we have developed a feasible and economic rac-GR24-assisted strategy that increases the amounts of biomass and astaxanthin generated by H. pluvialis cultures, and have provided novel insights into the mechanistic roles of rac-GR24 to achieve these effects.
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Chlorophyceae , Biomasa , Suplementos Dietéticos , XantófilasRESUMEN
Due to the recent boom in urbanisation, economy, and global population, the amount of waste generated worldwide has increased tremendously. The World Bank estimates that global waste generation is expected to increase 70% by 2050. Disposal of waste is already a major concern as it poses risks to the environment, human health, and economy. To tackle this issue and maximise potential environmental, economic, and social benefits, waste valorisation - a value-adding process for waste materials - has emerged as a sustainable and efficient strategy. The major objective of waste valorisation is to transit to a circular economy and maximally alleviate hazardous impacts of waste. This review conducts bibliometric analysis to construct a co-occurrence network of research themes related to management of five major waste streams (i.e., food, agricultural, textile, plastics, and electronics). Modern valorisation technologies and their efficiencies are highlighted. Moreover, insights into improvement of waste valorisation technologies are presented in terms of sustainable environmental, social, and economic performances. This review summarises highlighting factors that impede widespread adoption of waste valorisation, such as technology lock-in, optimisation for local conditions, unfavourable regulations, and low investments, with the aim of devising solutions that explore practical, feasible, and sustainable means of waste valorisation.
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Eliminación de Residuos , Administración de Residuos , Alimentos , Humanos , Plásticos , ResiduosRESUMEN
Thermal management plays a key role in improving the energy efficiency and sustainability of future building envelopes. Here, we focus on the materials perspective and discuss the fundamental needs, current status, and future opportunities for thermal management of buildings. First, we identify the primary considerations and evaluation criteria for high-performance thermal materials. Second, state-of-the-art thermal materials are reviewed, ranging from conventional thermal insulating fiberglass, mineral wool, cellulose, and foams, to aerogels and mesoporous structures, as well as multifunctional thermal management materials. Further, recent progress on passive regulation and thermal energy storage systems are discussed, including sensible heat storage, phase change materials, and radiative cooling. Moreover, we discuss the emerging materials systems with tunable thermal and other physical properties that could potentially enable dynamic and interactive thermal management solutions for future buildings. Finally, we discuss the recent progress in theory and computational design from first-principles atomistic theory, molecular dynamics, to multiscale simulations and machine learning. We expect the rational design that combines data-driven computation and multiscale experiments could bridge the materials properties from microscopic to macroscopic scales and provide new opportunities in improving energy efficiency and enabling adaptive implementation per customized demand for future buildings.
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Thermal management is the most critical technology challenge for modern electronics. Recent key materials innovation focuses on developing advanced thermal interface of electronic packaging for achieving efficient heat dissipation. Here, for the first time we report a record-high performance thermal interface beyond the current state of the art, based on self-assembled manufacturing of cubic boron arsenide (s-BAs). The s-BAs exhibits highly desirable characteristics of high thermal conductivity up to 21 W/m·K and excellent elastic compliance similar to that of soft biological tissues down to 100 kPa through the rational design of BAs microcrystals in polymer composite. In addition, the s-BAs demonstrates high flexibility and preserves the high conductivity over at least 500 bending cycles, opening up new application opportunities for flexible thermal cooling. Moreover, we demonstrated device integration with power LEDs and measured a superior cooling performance of s-BAs beyond the current state of the art, by up to 45 °C reduction in the hot spot temperature. Together, this study demonstrates scalable manufacturing of a new generation of energy-efficient and flexible thermal interface that holds great promise for advanced thermal management of future integrated circuits and emerging applications such as wearable electronics and soft robotics.
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According to the US Department of Energy, succinic acid (SA) is a top platform chemical that can be produced from biomass. Bread waste, which has high starch content, is the second most wasted food in the UK and can serve as a potential low cost feedstock for the production of SA. This work evaluates the environmental performance of a proposed biorefinery concept for SA production by fermentation of waste bread using a cradle-to-factory gate life cycle assessment approach. The performance was assessed in terms of greenhouse gas (GHG) emissions and non-renewable energy use (NREU). Waste bread fermentation demonstrated a better environmental profile compared to the fossil-based system, however, GHG emissions were about 50% higher as compared to processes using other biomass feedstocks such as corn wet mill or sorghum grains. NREU for fermentative SA production using waste bread was significantly lower (~ 46%) than fossil-based system and about the same as that of established biomass-based processes, thus proving the great potential of waste bread as a valuable feedstock for bioproduction of useful chemicals. The results show that steam and heating oil used in the process were the biggest contributors to the NREU and GHG emissions. Sensitivity analyses highlighted the importance of the solid biomass waste generated in the process which can potentially be used as fish feed. The LCA analysis can be used for targeted optimization of SA production from bread waste, thereby enabling the utilization of an otherwise waste stream and leading to the establishment of a circular economy.
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Pan , Ácido Succínico , Animales , Biomasa , Fermentación , Efecto Invernadero , Estadios del Ciclo de VidaRESUMEN
In this study, the ability of Yarrowia lipolytica to produce the recombinant lipase CalB from Candida antarctica, used as a model protein has been compared across different bioreactor processes using glycerol, a byproduct from the biodiesel industry as the main carbon source. Batch, pulsed fed-batch (PFB), and continuous fed-batch (CFB) strategies were first compared using classical stirred tank (STR) bioreactors in terms of biomass production, carbon source uptake, and lipase production. Additionally, an in situ fibrous bed bioreactor (isFBB) was developed using sugarcane bagasse as a cell immobilization support. The maximum lipase titer achieved using the isFBB culture mode was 38%, 33%, and 49% higher than those obtained using the batch, PFB, and CFB cultures, respectively. The lipase productivity in isFBB mode (142U/mL/h) was 1.4-fold higher than that obtained using batch free cell cultures. These results highlight that isFBB is an efficient technology for the production of recombinant enzymes.
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Yarrowia , Basidiomycota , Técnicas de Cultivo Celular por Lotes , Reactores Biológicos , Proteínas RecombinantesRESUMEN
Although fossil-based plastic products have many attractive characteristics, their production has led to severe environmental burdens that require immediate solutions. Despite these plastics being non-natural chemical compounds, they can be degraded and metabolized by some microorganisms, which suggests the potential application of biotechnologies based on the mechanism of plastic biodegradation. In this context, microbe-based strategies for the degradation, recycling, and valorization of plastic waste offer a feasible approach for alleviating environmental challenges created by the accumulation of plastic waste. This Minireview highlights recent advances in the biotechnology-based biodegradation of both traditional polymers and bio-based plastics, focusing on the mechanisms of biodegradation. From an application perspective, this Minireview also summarizes recent progress in the recycling and valorization of plastic waste, which are feasible solutions for tackling the plastic waste dilemma.