Use In Organic Media Research Articles

The Effect of Cocopeat Addition in Plant Media on The Quality and Quantity of Papaya Seeds (Carica papaya L.var.calina)

Papaya (Carica papaya L.) is one of the agricultural commodities that is widely cultivated by farmers in almost all parts of Indonesia. This plant is widely cultivated because varied consumption of papaya by the community makes the demand for fresh papaya fruit in the market always increase. Therefore, the cultivation of this plant is very important to be applied properly. Cocopeat is a powder which is a waste of coconut coir processing. Our previous research has shown that cocopeat is an organic material that has a positive role in the growth of patchouli seedlings. This study aimed to examine how the effect of the addition of cocopeat on the quality and quantity of growth of papaya seedlings (Carica papaya L.var.calina) on experimental land within the Universitas Negeri Manado (Unima) campus in Tondano. Experimental research was carried out with one factor, the concentration of cocopeat, with 5 levels 10, 20, 30, 40 and 50%. The control used was an organic media compounded by the analysis without using cocopeat. Each treatment and control was repeated 30 times so that the number of experimental units was 180 experimental units. Randomization was carried out by placing 10 rows and 18 columns at the Unima Patchouli Nursery Installation. The quantity parameter is the number of days the seeds germinated and the number of seeds that were successfully germinated in each treatment and control. Quality parameters include seedling height at the age of 2 months after germination (first germination); number of leaves, leaf size, wet weight and dry weight at 2 months of age. Based on the results, it can be concluded that the use of organic media with the addition of cocopeat at a concentration of 10-50% had a significant effect on leaf number, leaf size, plant height, stem diameter, wet weight, and dry weight of papaya plants in the early growth period. The addition of cocopeat concentration in the growing media will have an increasing effect on the observed parameters. Especially for the parameter of the number of days of germination after planting did not show a significant difference between all treatments.

A Graphene Oxide–Thioamide Polymer Hybrid for High‐Performance Supercapacitor Electrodes

The controlled chemical functionalization of graphene oxide (GO) represents a powerful strategy to finely tune its physical and chemical properties toward applications in energy storage. Herein, an unprecedented approach for the GO modification with thioamide‐based polymers featuring numerous heteroatoms (S,N,O) is reported, which is instrumental for achieving superior electrochemical performance in symmetric supercapacitors. While the electrochemical investigations in aqueous electrolytes reveal specific capacitance of 221 F g−1 at 1 A g−1, the use of organic media allows the specific capacitance to be boosted up to 340 F g−1. Additionally, the increase of operating window yields energy densities as high as 94.4 Wh kg−1, thereby exceeding state‐of‐the‐art performances of GO‐based supercapacitors. Furthermore, the symmetric devices exhibit great robustness in both aqueous and organic electrolytes as evidenced by an excellent stability after 5000 working cycles (>98% in H2SO4 and >90% in TEABF4/ACN).

Immobilization of Pseudomonas fluorescens lipase on chitosan crosslinked with polyaldehyde starch for kinetic resolution of sec-alcohols

The lipase from Pseudomonas fluorescens was immobilized on chitosan beads, with polyaldehyde starch (PAS) and glutaraldehyde (GA) being compared as crosslinking agents. With PAS, the best values for activity retention (53%), immobilization efficiency (94%), and hydrolytic activity in organic medium (156 U g−1) were obtained with an aldehyde content on chitosan of 3.5 mmol mg−1. With GA, the best results were an activity retention of 33%, an immobilization efficiency of 100%, and a hydrolytic activity in organic medium of 100 U g−1. When used in the kinetic resolution of secondary alcohols, the lipase immobilized on chitosan crosslinked with PAS gave a conversion of 43% in 24 h for (RS)-1-phenylethanol, and 36% in 36 h for (RS)-1-phenylpropanol. In both cases, the enantiomeric excess of the product (eep) was higher than 99%. These are promising results that support further studies into the immobilization of lipases on modified carbohydrates for use in organic media.

Acrylic Functionalization of Cellulose Nanocrystals with 2-Isocyanatoethyl Methacrylate and Formation of Composites with Poly(methyl methacrylate).

Cellulose nanocrystals (CNCs) derived from renewable plant-based materials exhibit strong potential for improving properties of polymers by their dispersal in the polymer matrix as a composite phase. However, the hydrophilicity and low thermal stability of CNCs lead to compromised particle dispersibility in common polymers and limit the processing conditions of polymer–CNC composites, respectively. One route that has been explored is the modification of CNCs to alter surface chemistry. Acrylic materials are used in a broad class of polymers and copolymers with wide commercial applications. Yet, the available methods for adding groups that react with acrylics to enhance dispersion are quite limited. In this work, a versatile chemical modification route is described that introduces acryloyl functional groups on CNCs that can in turn be polymerized in subsequent steps to create acrylic–CNC composites. The hydroxyl group on CNC surfaces was reacted with the isocyanate moiety on 2-isocyanatoethyl methacrylate (IEM), a bifunctional molecule possessing both the isocyanate group and acryloyl group. The resulting modified CNCs (mCNCs) showed enhanced hydrophobicity and dispersibility in organic solvent relative to unmodified CNCs. Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy, solid-state 13C nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis verified the surface modification and allowed an estimation of the degree of modification as high as 0.4 (26.7% surface hydroxyl substitution CNC). The modified CNCs were copolymerized with methyl methacrylate, and the composites had improved dispersion relative to composites with unmodified CNCs and enhanced (104%) tensile strength at 2 wt % CNC when compared to the neat poly(methyl methacrylate) (PMMA), indicating a benefit of the reactive acryloyl groups added to the CNC surface. Overall, the modification strategy was successful in functionalizing CNCs, opening possibilities for their use in organic media and matrices.

Can polyoxometalates enhance the capacitance and energy density of activated carbon in organic electrolyte supercapacitors?

Polyoxometalates (POMs) have been shown to work as faradaic additivesto activated carbon (AC) in acidic aqueous electrolytes. Yet, their use in organic media allows not only for added capacity but also higher voltage. Here we show that the tetraethylammonium derivative of phosphotungstate [PW12O40]3− (PW12) can be homogeneously distributed throughout the pores of activated carbon (AC) in organic solvents such as N,N’-dimethylformamide (DMF) and demonstrate the use of this hybrid electrode material in an organic electrolyte (1 M TEABF4 in acetonitrile) supercapacitor. Our results show the efficient electroactivity of the PW12 cluster even in the absence of protons, providing a higher voltage than aqueous electrolytes and fast and reversible redox activity. The hybrid material shows a combination of double-layer (AC) and redox (PW12) capacities leading to an increase (36%) in volumetric capacitance with respect to pristine AC in the same organic electrolyte (1 M TEABF4 in acetonitrile). Remarkably, we were able to quantify this increase as coming predominantly from non-diffusion-limited processes thanks to the utterly dispersed nature of POMs. Moreover, the hybrid material delivers a good rate capability and excellent cycle stability (93% retention of the initial capacitance after 10,000 cycles). This study has a profound significance on improving capacitance of carbon-based materials in organic electrolytes.

Cryostructuring of polymer systems. 47. Preparation of wide porous gelatin-based cryostructurates in sterilizing organic media and assessment of the suitability of thus formed matrices as spongy scaffolds for 3D cell culturing

AbstractNew gelatin-based cryostructurates have been elaborated and tested as scaffolds for three-dimensional (3D) cell culturing. Scaffold preparation included dissolution of Type A gelatin in dimethylsulfoxide, freezing of such solution, cryoextraction of crystalline phase with cold ethanol, cross-linking of gelatin with carbodiimide in ethanol medium, treatment of the matrix with ethanolic solution of Tris and tanning of the matrix with formaldehyde dissolved in ethanol. The use of organic media during all the preparation stages ensured the sterility of the scaffolds. The matrices thus prepared were seeded with human adipose tissue multipotent mesenchymal stromal cells to confirm the biocompatibility of scaffolds and their possibility to provide necessary environment for the cell growth and differentiation. The cells attached onto the surface of the pore walls, proliferated and differentiated into osteogenic and adipogenic lineages. These results demonstrate that gelatin-based cryostructurates prepared in the sterility ensuring organic media can be used as scaffolds for tissue engineering purposes.

Chitosan hydrogels: A new and simple matrix for lipase catalysed biosyntheses

Lipase from Mucor miehei was immobilized on chitosan hydrogels without using any activation agent. These low-cost and easy to prepare lipase-containing hydrogels could be considered as novel solid-phase biocatalysts for use in organic media. When they were applied as biocatalysts towards the model esterification reaction of propyl laurate synthesis they showed an optimum operation temperature at 30°C and maintained a high catalytic activity in various non-polar organic solvents. The higher initial esterification rates were obtained when biocatalysis took place in branched hydrocarbons where the initial rates recorded were twice the ones observed for straight hydrocarbons, being 0.22mM/min in isooctane and 0.11mM/min in hexane, respectively. The novel catalyst presented excellent reusability, with only 10% loss of activity after 12 uses, which is even higher than the one obtained by lipase-containing chitosan beads prepared with a cross-linker. Moreover, enzyme superactivity was evident for several runs.

Analysis of Aspergillus sp. lipase immobilization for the application in organic synthesis

Nowadays, for the industrial implementations, especially in the area of organic synthesis, immobilized enzymes are preferred over their soluble forms. Present study aimed to find fast, cost-efficient, and effective way of lipase immobilization for the use in organic media. Lipase from Aspergillus sp. (Resinase A 2X) was immobilized utilizing cross-linking of enzyme aggregates, covalent immobilization on magnetite particles and adsorption-immobilization using pyrolyzed sugar industry waste product as a novel type of carrier. Covalently- and adsorption-immobilized preparations exhibited greater specific activities (5.61±0.18U/mg and 14.2±0.63U/mg, respectively) in organic reaction media than the soluble form of the enzyme (0.06±0.01U/mg). Enzyme immobilized on the sugar industry waste pyrolyis product was determined as a best way to hyperactivate Resinase A 2X and was chosen for the synthesis of flavor and fragrance compound 2-phenylethyl butanoate. Furthermore, in order to optimize 2-phenylethyl butanoate synthesis conditions, central compositional experimental plan was designed using RSM. It showed that in optimal reaction conditions (4.5h at 40.7°C, with 0.1M of substrate) conversion higher than 90% can be achieved. Studies of the operational stability showed enhanced reusability of adsorption-immobilized lipase (with each cycle, efficiency of the 2-PB synthesis diminished by 20–30%). The use of the sugar industry waste pyrolysis product as a carrier provides a novel, cheap, fast, cost-efficient and eco-friendly way of immobilization with some crucial points to be noted for the best productivity.

THE USE OF MIXED BIOSOLIDS COMPOST AND SOIL AS AGIRICULTURAL MEDIA FOR PEPPER PRODUCTION

This study was conducted in two phases included, production of high quality composts from Bio solids, and the enrichment of this compost through mixing the waste with buffalo, poultry and sewage sludge at ratios of 1: 3 of each and 1: 1: 1: 2 one of them the decomposition and curing process was completed during 14 weeks. Chemical, physical and biological characteristics of mature compost as well as its elemental component and its suitability as agriculture media were determined. The results showed that Coliform bacteria and Salmonella and Shigella did not appear at the end of maturation. Total fungi count continued to increase to end of maturation when temperature fell to 30 °C. The second phase of the study included, a biological experiment of pepper at plastic house.The experiment included 24 treatment representing six cultural mediums , mixing with soil and fertilizers application. The results of biological experiment revealed that the use of organic media and their mixing with soil or chemical fertilization, led to a significant increase in plant height number of branches per plant, dry matter weight, the concentration of nitrogen, phosphorus and potassium in plant leaves, as well as the increase of early and total yield of pepper fruit compared with the soil alone.Mixing of municipal waste with poultry manure at 1:3 was the best among other mixtures. The use of mixed media with the soil at ratio1: 1 on the basis of size with half of the recommended amount of chemical fertilizer gave the best results in vegetative parameters and fruits yield compared with the use of organic media alone or using the recommended does of chemical fertilizer alone.

Use of sawdust, coco soil and pumice in hydroponically grown strawberry

Strawberry (Fragaria × ananassa Duch.) plants were grown hydroponically in different ratio of sawdust (Saw-100), coco soil (Coc-100) and/or pumice (Pum-100) mixtures. Leaf number doubled in plants grown in Saw-100 while runners (stolons) number increased up to 70% in plants grown in Coc-100 compared with the control treatment (Pum-100). Fruit number increased (up to 50%) in plants grown in Pum-100. Leaf stomatal conductance, photosynthetic rate and internal concentration of CO<sub>2</sub> differentiated according to the plant vegetative or reproductive stage and/or substrate medium. Leaf and stem fresh weight as well as leaf area was increased (up to 32, 24 and 44%, respectively) in case of Coc-100 compared with the Saw-100 or Pum-100. Plant yield was doubled when Pum-Saw (50-50) was used compared with the Saw-100, which is due to the reduced fruit number produced rather than the difference in fruit fresh weight. Substrate affected fruit quality parameters. The present findings highlight the putative use of organic medium i.e. Sawdust on top of the widely used coco soil as substrate medium in strawberry culture.

Immobilisation and application of lipases in organic media

Different methods of preparing lipases for use in organic media are critically reviewed. Solid lipase preparations can be made by typical immobilisation methods such as adsorption, entrapment, covalent coupling or cross-linking. Immobilisation is especially attractive for lipases because, in addition to the normal benefits of enzyme immobilisation, it can also lead to a considerable increase in catalytic activity, probably caused by conformational changes in the lipase molecules. Activation can be achieved, for example, using hydrophobic support materials or surfactants during the immobilisation procedure. Surfactants can also be used to solubilise lipases in organic media via the formation of hydrophobic ion pairs, surfactant-coated lipase or reversed micelles. Lipase preparation methods are discussed with regard to potential lipase inactivation and activation effects, mass transfer limitations, lipase stability and other features important for applications. The practical applications of lipases in organic media reviewed include ester synthesis, modification of triacylglycerols and phospholipids, fatty acid enrichment, enantiomer resolution, biodiesel production and acylation of carbohydrates and bioactive compounds.

Comparative Evaluation of Different Organic Media on Soil Chemical Composition, Growth, and Yield of Mushroom (Pleurotus tubergium L.)

The effectiveness of organic media as sources of nutrients on soil fertility, growth, and yield of mushroom (Pleurotus tubergium) was studied at Akure in the rainforest zone of Nigeria. The organic media were applied at 8 t/ha with an organo-mineral fertilizer medium as a reference material and unfertilized control treatment, replicated four times and arranged in a randomized complete block design. The result showed that the use of organic media increased significantly (P<0.05) crown width, stalk length, stalk girth, weight of fruiting bodies of mushroom and soil K, Ca, Mg, N, P, K, Ca, and O.M compared to the control treatment. Among the organic media, loamy soil had the highest values of mushroom crown width and weight of fruiting bodies relative to the others. However, the organo-mineral medium still had higher values of mushroom growth and yield than the soil organic media, but it may increase cost of production. For soil chemical composition, loamy soil treatment had the highest values of soil O.M and % N while oil palm bunch husk had the highest values of soil K, Ca, and Mg compared to other treatments. Wood ash treatment increased most the soil pH. In these experiments, loamy soil and soybean husk media applied at 8 t/ha were the most effective organic media for improving growth, yield of mushroom, and soil fertility.

Influence of Organophilization Process Variables in Bentonite Clays from Cubati-PB

This work aims at the development of organoclay from two varieties of bentonite for use in organic media using ionic surfactants, studying the influence of process variables in the organophilization process. We used the following materials: natural bentonite clay from Cubati-PB District, and the ionic quaternary ammonium salt: Praepagen WB® with 45% active matter. The clays were benefited and then turned into sodium form and subsequently into organoclays. The bentonites were characterized by laser diffraction (GA) X-ray fluorescence chemical composition (EDX), thermogravimetric analysis (TGA), thermogravimetry (DTA) and X-ray diffraction (XRD). The organoclays were characterized by (XRD) thermogravimetric analysis (TGA) and thermogravimetry (DTA). The results showed that the clay has potential for application in the organophilization process and that there is influence of process variables.

Optimized Biocatalytically Active Static Emulsions for Organic Synthesis in Nonaqueous Media

AbstractLiterature reports biocatalytically active static emulsions (BASE) as promising systems for the preparation of biocatalysts designed for synthetic use in organic media. Their excellent catalytic performance is attributed to the numerous micropools of dissolved enzymes independently dispersed in silicone beads. Here, a systematic study of the structure and morphology of BASE and optimization in terms of bead size distribution and overall catalytic performance is presented. The study relies on beads obtained by using a novel preparation method that enables a considerably improved reproducibility of the particle size and catalytic activity in separate batches. A large interfacial area of 0.023 m2 g−1 material was calculated. The adjustment of bead composition increased the apparent catalytic activity of entrapped lipase A from Candida antarctica (CalA) to 0.71 U gBASE−1, which is almost twofold higher than that previously reported. The specific activity remained in the range of prototype BASE (0.21 U mgprotein−1), which nevertheless is about 53 times higher than that reported for CalA entrapped in a sol–gel.

Properties of epoxide hydrolase from Aspergillus niger for the hydrolytic kinetic resolution of epoxides in pure organic media

The effects of various reaction parameters regarding activity, stability and apparent enantioselectivity of recombinant epoxide hydrolase (EH) from Aspergillus niger in organic media were investigated using the racemic para-chlorostyrene oxide as a model substrate. Depending on the nature of the organic solvent, EH responded differently to variations in initial a w and no correlation between the activity or enantiomeric ratio ( E) and the log P of solvent could be found. The most appropriate solvent medium and initial a w value was heptane and 0.9, respectively. The agitation speeds, where external substrate diffusional limitations were minimized, were defined. The study of internal diffusional limitations by mixing EH extract with BSA as an “inert” protein revealed the negative direct effect of BSA on the apparent enantioselectivity of EH when its relative concentration was too high. An acidic shift in the “pre-drying pH memory” of EH was observed in the heptane medium as compared to the pH activity profile in aqueous media. The temperature effect on enantioselectivity showed an increase in the apparent E-value with decreasing reaction temperature. From those data, the differential activation parameters ΔΔ H ‡ and ΔΔ S ‡ were determined to have the same negative sign and therefore their effects counteracted each other, however the former dominates at ambient temperature. The use of organic medium increased the half-life of EH by 2.0–13.8-fold as compared to aqueous medium at 27–59 °C, but it decreased the catalytic efficiency which was mainly due to an increase in the K m(app) value.

Stability of protein-coated microcrystals in organic solvents

Previously we reported a new high activity biocatalyst for use in organic media, termed protein-coated microcrystals (PCMC) [M. Kreiner, B.D. Moore, M.C. Parker, Chem. Commun. 12 (2001) 1906]. These novel biocomposites consist of water-soluble micron-sized crystalline particles coated with the given biocatalyst(s). Here we have looked at the stability of PCMC and their catalytic behaviour as a function of temperature in different organic media. PCMC show very good long-term stability at room temperature, when stored as suspensions in 1-propanol/1 wt.% H 2O. Candida antarctica lipase B and subtilisin Carlsberg (SC) in PCMC form retained nearly 90% of their initial activity after 1 year at room temperature (RT). The effects of temperature on the catalytic activity of SC-PCMC are solvent-dependant. In 1-propanol/1 wt.% H 2O, the initial rate increased when the temperature was elevated from 25 to 60 °C, whereas in acetonitrile/1 wt.% H 2O, SC-PCMC lost activity. The operational stability of PCMC is also solvent-dependant. In 1-propanol/1 wt.% H 2O, SC-PCMC lost only 16% of the initial activity after five batch cycles. Rather poor stability was found for SC-PCMC in THF/1% (v/v) H 2O and acetonitrile/1% (v/v) H 2O, with a rapid loss of activity within 4 h in a continuous flow reactor. However, during the next 4 days only a slow further deactivation was observed.

High-activity biocatalysts in organic media: solid-state buffers as the immobilisation matrix for protein-coated microcrystals.

Recently, we reported a new high-activity biocatalyst for use in organic media termed protein-coated microcrystals (PCMC) (Kreiner et al. [2001] Chem Commun 12:1096-1097). These novel particles consist of water-soluble micron-sized crystalline particles coated with the given biocatalyst(s) and are prepared in a one-step rapid dehydration process. In this study we extended the choice of immobilisation matrix from a simple inorganic salt, K(2)SO(4), to other compounds, both inorganic and zwitterionic, that act as solid-state buffers for biocatalysis in organic media. The catalytic activity of serine proteases subtilisin Carlsberg (SC) and alpha-chymotrypsin (CT) were significantly increased when coated onto the surface of solid-state buffers, as measured in acetonitrile/1wt% H(2)O. SC-PCMC with both organic and inorganic buffer carriers (Na-AMPSO, Na(2)CO(3), and NaHCO(3)) showed a 3-fold greater activity than that observed when using the unbuffered system (PCMC-SC/K(2)SO(4)). In comparison with freeze-dried preparations, this represents an approximately 3,000-fold increase in catalytic activity. Importantly, there is no improvement in catalytic activity upon external addition of any of the solid-state buffers to the reaction mixture. When acting in a solid-state buffer capacity, good buffering capacity was observed with SC-PCMC (3 wt% protein loading) prepared from a 1:1 mixture of AMPSO and AMPSO-Na. Alternatively, increasing the amount of solid-state buffer in the system allows improvement of the buffering. This can be achieved either by decreasing the protein loading of the SC/Na-AMPSO-PCMC or by addition of further external solid-state buffer to the reaction mixture. The catalytic activity of lipase-PCMC prepared from solid-state buffers was found less responsive to immobilisation.

Immobilization of horseradish peroxidase on chitosan for use in nonaqueous media

AbstractChitosan, a natural polysaccharide, was used for the covalent immobilization of horseradish peroxidase, an enzyme of high synthetic utility, with the carbodiimide method. Of the enzyme, 62% was immobilized on chitosan when 1‐ethyl‐3‐(3‐dimethylaminopropyl carbodiimide) was used as the peptide coupling agent. The influence of different parameters, such as the enzyme concentration, carbodiimide concentration, and incubation period, on the activity retention of the immobilized enzyme was investigated. Kinetic studies using horseradish peroxidase immobilized on chitosan revealed the effects of several parameters, such as the substrate hydrophilicity and hydrophobicity, the solubility of substrates in the medium, the solvent hydrophobicity, and the support aquaphilicity, on the catalytic activity of the immobilized enzyme in nonaqueous media. General rules for the optimization of solvents for nonaqueous enzymology based on the partitioning of the solvent were not applicable for the immobilized horseradish peroxidase. The catalytic efficiency was greatest when o‐phenylene diamine was used as the substrate and least when guaiacol was used. The aquaphilicity of the support played an important role in the kinetics of the immobilized horseradish peroxidase in water‐miscible solvents. The results were promising for the future development of chitosan‐immobilized enzymes for use in organic media. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1456–1464, 2003

Activity and Stability Studies Of Mucor miehei Lipase Immobilized in Novel Microemulsion-based Organogels

Lipase from Mucor miehei was immobilized in bis-(2-ethylhexyl)sulfosuccinate sodium salt (AOT) as well as lecithin water-in-oil (w/o) microemulsion-based organogels (MBGs) formulated with biopolymers such as agar and hydroxypropylmethyl cellulose (HPMC), respectively. These lipase-containing MBGs prove to be novel solid-phase catalysts for use in organic media. Using these organogels at 25°C, various esterification reactions in non-polar solvents as well as in solvent free systems were possible. Apparent lipase activity was influenced to some extent by the nature and the concentration of biopolymers used. Lipase stability in such MBGs is much higher than that observed in w/o microemulsions. MBGs containing lipase functioned effectively in repeated batch syntheses of fatty esters. Kinetic studies have shown that ester synthesis catalyzed by immobilized lipase occurs via the Ping-Pong bi-bi mechanism in which only inhibition by excess of alcohol has been identified. Values of all kinetic parameters were determined.

Development of Conducting Composite Materials for Electrochemical Sensing in Organic Media

Several electrochemical transducers have been developed for use in organic media. These transducers are based on rigid conducting dispersed composites prepared from a mixture of graphite powder in a polymer matrix. The behavior of composites based on silicone, several epoxies, polyester and polyurethane was studied in organic solvents like acetone, acetonitrile, ethanol, chloroform and tetrahydrofuran. The composites were characterized using cyclic voltammetry and were calibrated with ferrocene. Composites with silicone or epoxy showed a high stability in organic solvents. These composites have a homogeneous surface and they show high stability and reproducibility while performing electrochemical measurements. The surface of these devices can be renewed by a simple polishing procedure using alumina paper. The plastic nature of these materials makes them modifiable, permitting the incorporation of fillers before they are cured. To test their capacity for biosensing in organic media, the matrix of one transducer was biologically modified with horseradish peroxidase (HRP) producing a graphite-epoxy-HRP biocomposite. A biosensor built with this material responded linearly to lauroyl peroxide between 10−6 and 10−5 M in acetonitrile and the enzyme remained stable in the biocomposite.