Design of a 3D Amino-Functionalized Rice Husk Ash Nano-Silica/Chitosan/Alginate Composite as Support for Laccase Immobilization

Recycling of agro-industrial waste is one of the major issues addressed in recent years aimed at obtaining products with high added value as a future alternative to traditional ones in the per-spective of a bio-based and circular economy. One of the most produced wastes is rice husk and it is particularly interesting because it is very rich in silica, a material with a high intrinsic value. In the present study, a method to extract silica from rice husk ash (RHA) and to use it as a carrier for the immobilization of laccase from Trametes versicolor was developed. The obtained mesoporous nano-silica was characterized by X-ray diffraction (XRD), ATR-FTIR spectroscopy, Scanning Elec-tron Microscopy (SEM), and Energy Dispersive X-ray spectroscopy (EDS). A nano-silica purity of about 100 % was found. Nano-silica was then introduced in a cross-linked chitosan/alginate scaffold to make it more easily recoverable after reuse. To favor laccase immobilization into the composite scaffold, functionalization of the nano-silica with (γ-aminopropyl) triethoxysilane (APTES) was performed. The APTES/RHA nano-silica/chitosan/alginate (ARCA) composite al-lowed to obtain under mild conditions (pH 7, room temperature, 1.5 h reaction time) a robust and easily reusable solid biocatalyst with 3.8 U/g of immobilized enzyme which maintained 50 % of its activity after six reuses. The biocatalytic system, tested for syringic acid bioremediation, was able to totally oxidize the contaminant in 24 h

The Wide-field Spectroscopic Telescope (WST) Science White Paper

The Wide-field Spectroscopic Telescope (WST) is proposed as a new facility dedicated to the efficient delivery of spectroscopic surveys. This white paper summarises the initial concept as well as the corresponding science cases. WST will feature simultaneous operation of a large field-of-view (3 sq. degree), a high multiplex (20,000) multi-object spectrograph (MOS) and a giant 3x3 sq. arcmin integral field spectrograph (IFS). In scientific capability these requirements place WST far ahead of existing and planned facilities. Given the current investment in deep imaging surveys and noting the diagnostic power of spectroscopy, WST will fill a crucial gap in astronomical capability and work synergistically with future ground and space-based facilities. This white paper shows that WST can address outstanding scientific questions in the areas of cosmology; galaxy assembly, evolution, and enrichment, including our own Milky Way; origin of stars and planets; time domain and multi-messenger astrophysics. WST's uniquely rich dataset will deliver unforeseen discoveries in many of these areas. The WST Science Team (already including more than 500 scientists worldwide) is open to the all astronomical community. To register in the WST Science Team please visit this https URL (https://www.wstelescope.com/for-scientists/participate)

The Wide-field Spectroscopic Telescope (WST) Science White Paper

The Wide-field Spectroscopic Telescope (WST) is proposed as a new facility dedicated to the efficient delivery of spectroscopic surveys. This white paper summarises the initial concept as well as the corresponding science cases. WST will feature simultaneous operation of a large field-of-view (3 sq. degree), a high multiplex (20,000) multi-object spectrograph (MOS) and a giant 3x3 sq. arcmin integral field spectrograph (IFS). In scientific capability these requirements place WST far ahead of existing and planned facilities. Given the current investment in deep imaging surveys and noting the diagnostic power of spectroscopy, WST will fill a crucial gap in astronomical capability and work synergistically with future ground and space-based facilities. This white paper shows that WST can address outstanding scientific questions in the areas of cosmology; galaxy assembly, evolution, and enrichment, including our own Milky Way; origin of stars and planets; time domain and multi-messenger astrophysics. WST's uniquely rich dataset will deliver unforeseen discoveries in many of these areas. The WST Science Team (already including more than 500 scientists worldwide) is open to the all astronomical community. To register in the WST Science Team please visit this https URL<br/

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Comparison of lipase immobilization methods on spent coffee grounds (SCG) supports

Enzymes are currently used in a wide variety of industries and some of the most exploited are the lipases thanks to their unique versatility [1]. In nature they principally hydrolyze triglycerides, but they are also able to catalyze in vitro esterification, acidolysis, interesterificaton, transesterification, and aminolysis, together with a collection of the so-called promiscuous reactions [2]. However, how every other enzyme, lipases have a low stability and immobilization procedures are often applied to enhance their performances. The most common immobilization methodologies are covalent immobilization, physical adsorption, cross-linking, encapsulation, and entrapment on both synthetic and natural derived materials [3]. Although synthetic materials have many advantages, they are difficult to obtain and require higher additional costs. On the other hand, material derived from natural sources, like spent coffee grounds (SCG), have favorable physical-chemical characteristics and are also largely available and inexpensive. Coffee, in particular, had an estimated production of over 10 billion kg per year in 2020 [4] and is responsible for generating large quantities of residues that may represent a great pollution hazard if discharged into the environment. Therefore, the aim of this study is focused on the ideation of a suitable carrier for Candida Rugosa Lipase (CRL) from SCG. With this purpose SCG was pretreated in different ways to assure the best characteristics for each methodology of immobilization. The materials were characterized by SEM, IR, and elemental analysis. Subsequentially four different kinds of immobilization methods were evaluated: (i) adsorption, (ii) crosslinking, (iii) covalent binding after periodate oxidation of the support and (vi) covalent binding after activation of the support with glutaraldehyde (GLU). The optimal immobilization conditions were determined on the base of yield, efficiency, and recovery. [1] A. Houde, A. Kademi, D. Leblanc, Applied Biochemistry and Biotechnology 118 (2004) 155–170. [2] C. Ortiz, M.L. Ferreira, O. Barbosa, J.C.S. Dos Santos, R.C. Rodrigues, Á. Berenguer-Murcia, L.E. Briand, R. Fernandez-Lafuente, Catalysis Science &amp; Technology 9 (2019) 2380–2420. [3] B. Thangaraj, P.R. Solomon, ChemBioEng Reviews 6 (2019) 167–194. [4] International Coffee Organization (2022)

Renewable, Sustainable, and Natural Lignocellulosic Carriers for Lipase Immobilization: A Review

It is well-known that enzymes are molecules particularly susceptible to pH and temperature variations. Immobilization techniques may overcome this weakness besides improving the reusability of the biocatalysts. Given the strong push toward a circular economy, the use of natural lignocellulosic wastes as supports for enzyme immobilization has been increasingly attractive in recent years. This fact is mainly due to their high availability, low costs, and the possibility of reducing the environmental impact that can occur when they are improperly stored. In addition, they have physical and chemical characteristics suitable for enzyme immobilization (large surface area, high rigidity, porosity, reactive functional groups, etc.). This review aims to guide readers and provide them with the tools necessary to select the most suitable methodology for lipase immobilization on lignocellulosic wastes. The importance and the characteristics of an increasingly interesting enzyme, such as lipase, and the advantages and disadvantages of the different immobilization methods will be discussed. The various kinds of lignocellulosic wastes and the processing required to make them suitable as carriers will be also reported

Immobilization of lipase on spent coffee grounds by physical and covalent methods: A comparison study

Spent coffee grounds were treated to obtain suitable carriers for both physical and covalent immobilization of Candida rugosa lipase. In the first case, physical adsorption was directly performed after water/organic solvent extraction of the interferents from the support, while in the second case the delignification and the activation of the support with glutaraldehyde or KIO4 were necessary. The support materials obtained were characterized by Fourier transform attenuated total reflection IR, elemental analysis, and scanning electron microscope. Each immobilization method was investigated to obtain the best insoluble biocatalyst immobilized activity, efficiency, and recovery. Emphasis was given to the study of the water/organic solvent ratio in the immobilization mixture as it has proven to be a decisive parameter. The optimized immobilized biocatalyst obtained by adsorption mechanism showed up to 33 U∙g-1 of immobilized enzyme activity, and a higher pH, thermal, and storage stability than the free lipase. This solid biocatalyst also preserved 100 % of its activity after four recycles in p-nitrophenyl palmitate hydrolysis in hexane medium and permitted an almost 60 % conversion of milk fats in fatty acids after 18 h of reaction, maintaining this value for three reuses

Spent coffee grounds as a cheap and renewable feedstock for the immobilization of candida rugosa lipase (CRL)

Spent coffee grounds as a cheap and renewable feedstock for the immobilization of Candida Rugosa Lipase (CRL) Viviana Chiappini1*, Paolo Amadoro1, Anna Maria Girelli1 1Department of Chemistry, La Sapienza University, Rome, Italy *[email protected] Enzyme immobilization is a vastly used tool to enhance the stability and the reusability of biocatalysts, allowing the development of greener chemical and industrial processes. One of the main factors that defines the success of the immobilization is the nature of the support. Considering that synthetized specific supports may be very expensive, the scientific attention has been focused on the development of cheaper supports with the proper characteristics for a good immobilization [1]. In this context, lignocellulosic waste materials, such as spent coffee grounds (SCG), represent a great opportunity considering their large availability, inexpensiveness, and chemical-physical properties (large surface area, high porosity, high rigidity, and presence of active functional groups). In particular, spent coffee grounds, thanks to their very variable pore size, possess a opened structures with high adsorption capacity, large surface area and great pore volume, to the point that they have been exploited for adsorbents production [2,3]. It is common knowledge that porous materials like SCG are especially useful in the immobilization of proteins, such as enzymes, compared to non-porous materials. Therefore, also considering the possibility to reuse a waste material which would contribute to environmental pollution if not properly disposed, using SCG as support appeared to be a good choice for the synthesis of an efficient biocatalyst. The aim of this study was to investigate the possibility to use SCG as a solid carrier for the immobilization of Candida Rugosa Lipase (CRL). With this purpose it was pretreated and digested to eliminate lignin and make the cellulose more available for binding reaction with the lipase. The materials were characterized by SEM, IR, and elemental analysis. Subsequentially two different kinds of lipase covalent immobilization methods were evaluated: (i) binding after periodate oxidation of the support and (ii) binding after activation of the support with glutaraldehyde (GLU). The optimal immobilization conditions were determinated for each method and the yield, efficiency and recovery of each one were compared. 1. [1] A.M. Girelli, M.L. Astolfi, F.R. Scuto, Chemosphere, 2020, 244, 125368. 2. [2] J. Roh, H.N. Umh, C.M. Yoo, S. Rengaraj, B. Lee, Y. Kim, Korean Journal of Chemical Engineering, 2012, 29, 903-907. 3. [3] A. V. Buntić, M.D. Pavlović, D.G. Antonović, S.S. Šiler-Marinković, S.I. Dimitrijević-Branković, Heliyon, 2016, 2, e00146

Rice husk ash as a green feedstock for the extraction of nano-silica and its application in the synthesis of an efficient solid biocatalyst

Every year, millions of tons of rice are produced. About 20% of the rice weight is constituted of what is called rice husks (RH), which are removed during the milling process, generating approximately 150 million tons per year of residue [1]. Generally, the disposal of this waste in open fields or landfill creates environmental and human health problems [2]. The high calorific value of RH makes it a good and low-cost source of renewable energy, but high quantities of rice husk ash (RHA) (17- 26 %) rich in silica (90 - 95 %) are generated [3]. This disadvantage, however, can be transformed into a strength, because from this waste it is possible to extract a raw material widely used for industrial applications like the production of ceramics, electronics, catalysts, pharmaceutics, and other materials, i.e., silica. The extraction process from RHA presents the fundamental advantage of having a significantly lower environmental impact as compared to its commonly employed counterpart, i.e., sand extraction. Quartz extraction from natural sand exploits a non-renewable feedstock and not only destroys the natural landscape where the quarries are placed but also introduces a great number of pollutants into the environment both during the raw material acquisition and the lengthy procedures of silica extraction. Hence, with a view to developing a circular economy, this work aimed to reuse waste (RHA) as a new feedstock for silica extraction to be used in the synthesis of a biomaterial for enzymatic immobilization. That allows to recycle of something that would otherwise be discarded and may potentially save on the costs of industrial processes. In fact, among the main advantages of enzymatic immobilization are present the stabilization and improved robustness of the immobilized enzyme, as well as the possibility of reusing it, all factors that make it possible to significantly reduce the costs of an industrial process. To achieve this purpose, the development of a solid biocatalyst based on composite polymer scaffolds containing RH nano-silica (RH/NS) for the immobilization of laccases from Trametes Versicolor was investigated. Laccases were chosen as catalysts since they are considered versatile enzymes capable of oxidizing many phenolic and non-phenolic molecules thanks to their low substrate specificity, using oxygen as the electron acceptor, and generating water as a by-product. The nano-silica extraction process obtained from rice husk was optimized and the mesoporous nano-silica was characterized by X-ray diffraction (XRD), ATR-FTIR spectroscopy, Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller analysis (BET), and Energy Dispersive X-ray spectroscopy (EDX). XRD patterns revealed the amorphous nature of the extracted nano-silica while EDX confirmed the presence of pure SiO2 containing several silanol and siloxane groups as evidenced by ATR-FTIR analysis. So, an amorphous nano-silica with a purity of 99.6 %, size of 70-100 nm, a surface area of 111 m2/g, and porosity of 77 % was obtained by thermal treatment at 550 °C and extraction process using rice husks. The nano-silica obtained was then introduced in a crosslinked chitosan-alginate scaffold and then functionalized with γ-aminopropyltriethoxysilane (APTES) to create a solid support suitable for enzymatic immobilization. The use of a three-dimensional polymer structure was aimed at guaranteeing an easier recovery of the biocatalyst from the reaction mixture as well as better stability of the enzyme under varying experimental conditions. Using thermogravimetric analysis (TGA) was demonstrated that the introduction of RH/NS allowed an improvement in the thermal and mechanical properties of the chitosan-alginate scaffold. Subsequentially, the synthesized scaffold was used for laccase covalent immobilization exploiting the amine groups inserted with APTES, which guaranteed the laccase immobilization in a conformation favorable for the interaction with the substrates (ABTS and syringic acid). The solid biocatalyst obtained evidenced high immobilized activity (3.8 U/g) and good reusability in the oxidation of ABTS (about 50 % up to 6 cycles). Furthermore, the biocatalyst was employed in syringic acid removal from water, since the use of immobilized laccases for the treatment of organic contaminants is considered a promising new and eco-friendly for bioremediation of polluted sites. The synthesized biocatalyst was able to totally oxidize syringic acid in 24 h, as shown by the HPLC-DAD analysis performed. To sum up, this work refined a method to extract highly pure nano-silica from rice husk ash and, for the first time, a crosslinked chitosan-alginate scaffold containing RH nano-silica was successfully used for laccase immobilization to obtain an efficient, cheap, and easy-to-use biocatalyst. Furthermore, it should be mentioned that the synthesized nano-silica was not only an excellent filler for composite materials and support for enzymatic immobilization but may also become a potential resource of low-cost precursors for the production of high-value-added silica-based materials for industrial uses. [1] P.P. Nayak, S. Nandi, A.K. Datta, Eng. Reports. 1 (2019) 1–13. https://doi.org/10.1002/eng2.12035. [2] R. Pode, Renew. Sustain. Energy Rev. 53 (2016) 1468–1485. https://doi.org/10.1016/j.rser.2015.09.051. [3] J.G. Buta, N. Balasubramanian, Int. J. Sci. Eng. Res. 8 (2017) 1158–1169