Presence Of Polyethylene Glycol Research Articles

The effects of polyethylene glycol on the nucleation and growth of DNA-functionalized gold nanoparticles crystals

This study presents findings on the crystal growth of DNA-functionalized gold nanoparticles (DNA-AuNPs) in the presence of polyethylene glycol (PEG), serving as an additive. Utilizing optical microscopy, UV–Vis spectroscopy, dynamic light scattering and small angle x-ray scattering, we observed enhanced crystal nucleation and growth facilitated by PEG. This effect is attributed to PEG’s promotion of the overall crystallization process of DNA-AuNPs. Furthermore, we examined the influence of PEG on short-range interactions between DNA-AuNPs, where DNA binding occurs, and long-range interactions in colloidal solutions. The results suggest that PEG plays a crucial role in both promoting crystal nucleation and influencing the interactions between DNA-AuNPs at various distances, shedding light on its potential impact on DNA-AuNP crystal formation.

Double in-situ lignin modification in surfactant-assisted glycerol organosolv pretreatment of sugarcane bagasse towards efficient enzymatic hydrolysis

Organosolv pretreatment effectively fractionates lignocellulosic biomass for efficient enzymatic hydrolysis, yielding fermentable sugars. However, substantial lignin redeposition on the substrate surface and residual lignin content exacerbate lignin’s inhibitory effects on subsequent enzymatic hydrolysis. An in-situ lignin modification is proposed to address this challenge by incorporating polyethylene glycol (PEG) series into glycerol organosolv (GO) pretreatment. According to the results obtained, PEG-assisted GO pretreated substrate exhibited significantly increased sugar yield during enzymatic hydrolysis, particularly with PEG 4000, showing 35.4% higher glucose yield over 72 h. The improved glucose yield with PEG could be attributed to changes in the physicochemical structure and properties of residual lignin, mitigating its non-productive interaction with cellulase enzymes. PEG's presence in GO pretreatment also increased β-O-4 linkages preservation by 55% and reduced phenolic hydroxyl groups by 28% in lignin fragments versus no surfactants. This outcome resulted from introducing glycerol and PEG hydroxyl tails into the lignin structure, forming α-etherified lignin and rendering it more hydrophilic. Simulations confirmed strong Van Der Waals and hydrogen bonding interactions between lignin units and PEG, hindering lignin fragments repolymerization. Incorporating PEG in the organosolv pretreatment proves highly beneficial for cellulase-mediated lignocellulosic biorefinery, resembling a lignin-first strategy. The optimized process enables efficient biomass utilization for sustainable fuels and chemicals production.

CD4+ T cell-targeting immunoliposomes for treatment of latent HIV reservoir

Active targeting nano-delivery is a promising approach to enhance therapeutic efficacy and specificity to the target cells. Liposomes (LPs) have been widely studied for the active targeting delivery due to their low toxicity, biodegradability, biocompatibility, and feasibility of surface medication to provide the interactions with cell receptors. One of the strategies is to functionalize the surface of LPs with monoclonal antibodies (mAbs) to obtain immunoliposomes (imLPs) that recognize specific receptors on target cells. Among several target cells, CD4+ T cells are known for playing a pivotal role in controlling the immune system in several diseases, including cancers, inflammatory diseases, and viral infections, particularly HIV-1. Here, we demonstrate two methods for conjugating αCD4 mAb with imLPs for specific targeting of CD4+ T cells that can harbor viral genome and serve as a predominant latent HIV reservoir. LPs conjugated with αCD4 mAb via neutravidin-biotin linkage were used for selectively targeting CD4+ J-Lat 10.6 cells. We demonstrate, via flow cytometry, the importance of the conjugation step, mAb density, and the presence of polyethylene glycol (PEG) for effective drug delivery to CD4+ T cells. The cellular uptake of imLPs is substantially higher if the imLPs are functionalized with the pre-conjugated αCD4 mAb-neutravidin complex. Furthermore, imLPs loaded with HIV-1 latency reversing agent, suberoylanilide hydroxamic acid (SAHA), could reactivate the J-Lat 10.6 cells, suggesting that the αCD4-imLPs could be potentially used as a targeted drug delivery system for HIV-1 latency reactivation or other CD4-targeted immunotherapies.

Development and characterization of porous membranes based on PPSU/PES using polyethylene glycol as porogen: Application for cobalt removal by polyelectrolyte‐enhanced ultrafiltration

AbstractBACKGROUNDIn this work, a polyphenylsulfone/polyethersulfone (PPSU/PES) composite membrane was successfully prepared using the phase‐inversion method in the presence of polyethylene glycol (PEG) as a hydrophilic additive. The effect of concentration of PEG (0, 2, 4 and 6 wt%) was investigated by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and contact angle analysis.RESULTSThe obtained results confirmed that the morphology and hydrophilicity of the porous membrane varied with the addition of PES as reinforcing agent and the PEG concentration as porogen. SEM results confirmed that the membranes obtained have a high permeability with a finger‐shaped structure and that the size and density of the pores increase with an increase in the incorporated PEG. The contact angle was decreased and the porosity of the PPPn blend membranes was increased from 16.06 for the neat PPSU membrane to 385.3 L h−1 m−2 bar−1 for the PPP6 membrane. A strong interaction between the components (PPSU, PES and PEG) was revealed by FTIR spectroscopy and TGA.CONCLUSIONThe filtration results showed that PPP2 is the better formulation of the dope suspension in the range of ultrafiltration membranes in terms of flux (179.3 L h−1 m−2 bar−1) and bovine serum albumin retention (94%). The application of polyelectrolyte‐enhanced ultrafiltration using polyethylenimine (PEI) for the removal of cobalt ions afforded high removal rates (92.5%). The optimal performances were obtained at pH ≥ 4, transmembrane pressure of 4 bar and 1200 ppm of PEI. © 2023 Society of Chemical Industry (SCI).

Impact of the Membrane Structure of the Stationary Phase on Steric Exclusion Chromatography (SXC) of Lentiviral Vectors.

For steric exclusion chromatography (SXC), hydrophilic stationary phases are used to capture the target molecule in the presence of polyethylene glycol. The influence of the structure and pore size of the stationary phase on the process requirements are not yet well understood. To better understand the SXC process, membranes with different pore sizes that served as a stationary phase were compared for the purification of lentiviral vectors (LVs). A design of experiments (DoE) was performed to assess the combined impact of PEG concentration and membrane pore size on the purification performance. A visualization experiment showed that the LVs were captured on the first membrane layer for a pore size up to 2.2 µm, and for a pore size larger than 2.2 µm, LVs were also partly found on the second and third membrane layers. Moreover, we could observe that increasing membrane pore size requires a higher PEG concentration to achieve comparable LV recoveries. Using five membrane layers as a stationary phase was sufficient to achieve good performance, supporting the visualized capture results. In conclusion, we could show that each stationary phase has its optimal PEG buffer compositions for SXC, depending on the membrane structure and pore size.

Controlling the protein corona of polymeric nanocapsules: effect of polymer shell on protein adsorption.

Understanding the interactions between nanocarriers and plasma proteins is essential for controlling their biological fate. Based on the reported potential of polymeric nanocapsules (NCs) for the targeted delivery of oncological drugs, the main objective of this work has been to investigate how the surface chemical composition influences their protein corona fingerprint. Thus, we developed six NC prototypes with different polymer shells and physicochemical properties and quantified the amount of protein adsorbed upon incubation in human plasma. Using sequential window acquisition of all theoretical mass spectra (SWATH-MS) and following the Minimum Information about Nanomaterial Biocorona Experiments (MINBE) guidelines, we identified different protein corona patterns. As expected, the presence of polyethylene glycol (PEG) in the polymer shell reduced the protein corona, particularly the adsorption of immunoglobulins. However, by comparing the different prototypes, we concluded that the protein adsorption pattern was not exclusively driven by PEG. In fact, a highly PEGylated prototype exhibited intense apolipoprotein IV adsorption. On the other hand, we also observed that polymeric NCs containing 1,2-dioleoyl-3-trimethylammonium propane (DOTAP) exhibited high adsorption of vitronectin, a protein that is known for enhancing the uptake of nanosystems by lung epithelium and several cancer cells. Overall, the gathered information allowed us to identify promising polymeric NCs with an expected prolonged circulation time, enhanced tumor targeting, liver accumulation, and preferential uptake by the immune system. In this sense, the analyses of the protein corona performed along this work will hopefully contribute to advancing a new generation of rationally designed nanometric drug delivery systems.

Influence of Radical Scavenger on Radiation Synthesis of Graphene Oxide/TiO2 Nanotubes/Ag Nanoparticles Nanocomposites and Their Dye Photodegradation Efficiency

Aqueous solutions of graphene oxide (GO), TiO2 nanotubes (TNTs), and silver nanoparticles (AgNPs) were synthesized through a facile, single-step radiolytic method at room temperature and ambient pressure. The resulting material, referred to as GO-TNTs-AgNPs (GTA), was investigated for its potential application in the photodegradation of Rhodamine-B (RhB) dye. This synthesis process relies on the interaction of high-energy gamma rays from a 60Co source with the water in the aqueous solutions. The main objective of this study was to evaluate the effect of irradiation dose and the presence of polyethylene glycol (PEG) solution on the combination within the nanocomposite materials. The inefficiency of GTA synthesis experimentally was in agreement with the hydroxyl radical (HO•) scavenger. Then, the irradiated materials were structurally characterized using various spectroscopic methods (Fourier transform infrared (FTIR), X-ray diffraction (XRD), Raman spectroscopy, and ultraviolet-visible absorption (UV–Vis)). Scanning electron microscopy (SEM) studies reveal the variable morphology of nanocomposites. GTA samples in water exhibited significantly higher degradation efficiency on Rhodamine B dye under natural sunlight irradiation conditions.

INVESTIGATING THE EFFECT OF MICROWAVE IRRADIATION TIME, POLYETHYLENE GLYCOL CONCENTRATION AND pH ON THE PROPERTIES OF Mg-BASED BACTERIAL CELLULOSE NANOBIOCOMPOSITE

INVESTIGATING THE EFFECT OF MICROWAVE IRRADIATION TIME, POLYETHYLENE GLYCOL CONCENTRATION AND pH ON THE PROPERTIES OF Mg-BASED BACTERIAL CELLULOSE NANOBIOCOMPOSITE

Constructing Randomly Lamellar HKUST–1@Clinoptilolite through Polyethylene Glycol—Assisted Hydrothermal Method and Coordinated Complexation for Enhanced Adsorptive Separation for CO2 and CH4

Clinoptilolite (CP) was successfully synthesized via a hydrothermal route in the presence of polyethylene glycol (PEG), and it was then delaminated by washing using Zn2+ containing acid. HKUST-1, as one kind of the Cu-based MOFs, showed a high CO2 adsorption capacity owing to its large pore volume and specific surface area. In the present work, we selected one of the most efficient ways for preparing the HKUST-1@CP compounds via coordination between exchanged Cu2+ and ligand (trimesic acid). Their structural and textural properties were characterized by XRD, SAXS, N2 sorption isotherms, SEM, and TG-DSC profiles. Particularly, the effect of the additive PEG (average molecular weight of 600) on the induction (nucleation) periods and growth behaviors were detailed and investigated in the hydrothermal crystallization procedures of synthetic CPs. The corresponding activation energies of induction (En) and growth (Eg) periods during crystallization intervals were calculated. Meanwhile, the pore size of the inter-particles of HKUST-1@CP was 14.16 nm, and the BET specific area and pore volume were 55.2 m2/g and 0.20 cm3/g, respectively. Their CO2 and CH4 adsorption capacities and selectivity were preliminarily explored, showing 0.93 mmol/g for HKUST-1@CP at 298 K with the highest selective factor of 5.87 for CO2/CH4, and the dynamic separation performance was evaluated in column breakthrough experiments. These results suggested an efficient way of preparing zeolites and MOFs composites that is conducive to being a promising adsorbent for applications in gas separation.

Hydrothermal Synthesis of Functionalized Carbon Nanodots and Their Clusters as Ionic Probe for High Sensitivity and Selectivity for Sulfate Anions with Excellent Detection Level.

Nitrogen-doped carbon nanodots (CNDs) were synthesized and utilized as sensing probes to detect different anions and metallic ions within aqueous solutions. The pristine CNDs were developed through a one-pot hydrothermal synthesis. o-Phenylenediamine was used as the precursor. A similar hydrothermal synthesis technique in the presence of polyethylene glycol (PEG) was adopted to form the PEG-coated CND clusters (CND-100k). Through photoluminescence (PL) quenching, both CND and PEG-coated CND suspensions display ultra-high sensitivity and selectivity towards HSO4- anions (Stern-Volmer quenching constant (KSV) value: 0.021 ppm-1 for CND and 0.062 ppm-1 for CND-100k) with an ultra-low detection limit (LOD value: 0.57 ppm for the CND and 0.19 ppm for CND-100k) in the liquid phase. The quenching mechanism of N-doped CNDs towards HSO4- ions involves forming the bidentate as well as the monodentate hydrogen bonding with the sulfate anionic moieties. The detection mechanism of metallic ions analyzed through the Stern-Volmer formulation reveals that the CND suspension is well suited for the detection of Fe3+ (KSV value: 0.043 ppm-1) and Fe2+ (KSV value: 0.0191 ppm-1) ions, whereas Hg2+ (KSV value: 0.078 ppm-1) sensing can be precisely performed by the PEG-coated CND clusters. Accordingly, the CND suspensions developed in this work can be employed as high-performance PL probes for detecting various anions and metallic ions in the liquid phase.

Research in the area of obtaining of activated alumina. Part 5. Various technological approaches to the process of fine grinding of high-alumina raw materials

The results of studying the process of fine grinding of α-Al2O3 in the presence of polyethylene glycol (PEG) and an antistatic composition are presented. It is shown that the main reason for the agglomeration of fine particles is the effect of the appearance of an electrostatic surface charge. The introduction of PEG prevents the appearance of a «pseudo-viscous grinding medium», removing the excess electrostatic charge on the surface of newly formed ultrafine particles, and also intensifies the process of abrasion of primary alpha-alumina crystals. The antistatic composition successfully neutralizes the surface electrical charge, but does not have the effect of a grinding aid.

A Nano-QSTR model to predict nano-cytotoxicity: an approach using human lung cells data

BackgroundThe widespread use of new engineered nanomaterials (ENMs) in industries such as cosmetics, electronics, and diagnostic nanodevices, has been revolutionizing our society. However, emerging studies suggest that ENMs present potentially toxic effects on the human lung. In this regard, we developed a machine learning (ML) nano-quantitative-structure-toxicity relationship (QSTR) model to predict the potential human lung nano-cytotoxicity induced by exposure to ENMs based on metal oxide nanoparticles.ResultsTree-based learning algorithms (e.g., decision tree (DT), random forest (RF), and extra-trees (ET)) were able to predict ENMs’ cytotoxic risk in an efficient, robust, and interpretable way. The best-ranked ET nano-QSTR model showed excellent statistical performance with R2 and Q2-based metrics of 0.95, 0.80, and 0.79 for training, internal validation, and external validation subsets, respectively. Several nano-descriptors linked to the core-type and surface coating reactivity properties were identified as the most relevant characteristics to predict human lung nano-cytotoxicity.ConclusionsThe proposed model suggests that a decrease in the ENMs diameter could significantly increase their potential ability to access lung subcellular compartments (e.g., mitochondria and nuclei), promoting strong nano-cytotoxicity and epithelial barrier dysfunction. Additionally, the presence of polyethylene glycol (PEG) as a surface coating could prevent the potential release of cytotoxic metal ions, promoting lung cytoprotection. Overall, the current work could pave the way for efficient decision-making, prediction, and mitigation of the potential occupational and environmental ENMs risks.

Structure directing agent assisted solvothermal synthesis of octahedral WO3·nH2O large microcrystals: Study of electrochemical and optical properties

In the present study, the growth of tungsten trioxide crystals by solvothermal method was investigated in the presence of polyethylene glycol (PEG) and L-3,4-dihydroxyphenylalanine (L-dopa) as the structure directing agents in acetonitrile solution. The change of crystal faces consisting of stacked layers to very smooth facets is attributed to the change of the crystal growth mechanism from a three-step mechanism in the absence of PEG and L-dopa to a two-step mechanism in their presence. The rate of formation and growth of crystals in the presence of 5 w% of PEG increases significantly compared to those grown in the absence of PEG. The crystals solvothermally grown in the presence of L-dopa were of the octahedral WO3·0.5H2O with fully smooth faces, and those grown in the presence of PEG were the octahedral and rectangular microcrystals of WO3·H2O The transparency and electro-optical properties of the prepared crystal layers are improved in the presence of PEG. The dynamic potential electropolymerization of aniline and the formation of a thin layer of polyaniline on tungsten trioxide crystals were performed and the properties of the obtained core–shell hybrid film were studied. It was shown that covering the crystals with a very thin layer of polyaniline helps to stabilize their electrochemical and optical properties.

Halloysite nanotubes for regulating thermodynamics and kinetics of polysulfone/poly (ethylene-co-vinyl alcohol) membranes with enhanced permeability

Controlling membrane morphology is crucial to improving the mechanical strength (MS) and hydrophilicity of porous membranes. Here we report on the fabrication of mixed matrix membranes (MMMs) free of macrovoids via non-solvent-induced phase separation (NIPS). Hydrophilic Halloysite nanotubes (HNTs) and poly (ethylene-co-vinyl alcohol) (EVOH) were mixed with Hydrophobic polysulfone (PSF) in the presence of polyethylene glycol (PEG) to fabricate MMMs. The results showed the formation of PSF/EVOH-MMMs with a spongy structure when the content of HNTs varied from 0.06- 0.12 wt.%, owing to the formation of strong hydrogen bonds between PSF, EVOH, PEG, and HNTs, confirmed by molecular dynamics (MD) simulations. The MS of MMMs with 0.12 wt.% HNTs was increased 2.2-fold (up to 6.22 MPa), while the contact angle (CA) was lowest at 47.42 ± 1.9°. In addition, the water permeability increased by a factor of 1.7 up to 419 L m−2 h−1 bar−1. The rejection rates of MMMs (M12) for oil and BSA were >90% and >95%, respectively. While the MMMs had > 90% flux recovery for both oil and BSA. We predict that this study will provide a method for controlling dope thermodynamics, formation dynamics, and morphology of MMMs while maintaining promising properties for improved separation performance.

Resolving the enthalpy of protein stabilization by macromolecular crowding.

Proteins in the cellular milieu reside in environments crowded by macromolecules and other solutes. Although crowding can significantly impact the protein folded state stability, most experiments are conducted in dilute buffered solutions. To resolve the effect of crowding on protein stability, we use 19 F nuclear magnetic resonance spectroscopy to follow the reversible, two-state unfolding thermodynamics of the N-terminal Src homology 3 domain of the Drosophila signal transduction protein drk in the presence of polyethylene glycols (PEGs) of various molecular weights and concentrations. Contrary to most current theories of crowding that emphasize steric protein-crowder interactions as the main driving force for entropically favored stabilization, our experiments show that PEG stabilization is accompanied by significant heat release, and entropy disfavors folding. Using our newly developed model, we find that stabilization by ethylene glycol and small PEGs is driven by favorable binding to the folded state. In contrast, for larger PEGs, chemical or soft PEG-protein interactions do not play a significant role. Instead, folding is favored by excluded volume PEG-protein interactions and an exothermic nonideal mixing contribution from release of confined PEG and water upon folding. Our results indicate that crowding acts through molecular interactions subtler than previously assumed and that interactions between solution components with both the folded and unfolded states must be carefully considered.

Liposomal form of erlotinib for local inhalation administration and efficiency of its transport to the lungs

This contribution is focused on the preparation of a liposomal drug delivery system of erlotinib resisting the nebulization process that could be used for local treatment of non-small-cell lung cancer. Liposomes with different compositions were formulated to reveal their influence on the encapsulation efficiency of erlotinib. An encapsulation efficiency higher than 98 % was achieved for all vesicles containing phosphatidic acid (d ≈ 100 nm, ζ = – 43 mV) even in the presence of polyethylene glycol (d ≈ 150 nm, ζ = – 17 mV) which decreased this value in all other formulas. The three most promising formulations were nebulized by two air-jet and two vibrating mesh nebulizers, and the aerosol deposition in lungs was calculated by tools of computational fluid and particle mechanics. According to the numerical simulations and measurements of liposomal stability, air-jet nebulizers generated larger portion of the aerosol able to penetrate deeper into the lungs, but the delivery is likely to be more efficient when the formulation is administered by Aerogen Solo vibrating mesh nebulizer because of a higher portion of intact vesicles after the nebulization. The leakage of encapsulated drug from liposomes nebulized by this nebulizer was lower than 2 % for all chosen vesicles.

The involvement of metallothioneins and stress markers in response to osmotic stress in Avena sativa L.

AbstractOsmotic stress frequently caused by drought is the most threatening environmental stress that remarkably reduces crop yield. Oat (Avena sativa L.) is sensitive to water deficiency during growth. Plant metallothioneins (pMTs) show tremendous promise in enhancing general stress tolerance in plants. This study aimed to verify whether pMTs and elements of the antioxidant defence system protect oat against osmotic stress. Coding and genomic regions of A. sativa L. MTs belonging to three different types were cloned. To evaluate the role of MTs in osmotic stress, the expression of genes encoding AsMT1‐3 was checked by qRT‐PCR in the roots and shoots of oat plants growing in a hydroponic culture in the presence of polyethylene glycol (PEG 6000) and mannitol. The expression of AsMT1‐3 changed in response to osmotic stress; however, the changes depended on the type of MT and the treatment. The amount of AsMT3 transcript was about five‐fold and nine‐fold higher in shoots and roots, respectively, in the presence of mannitol. To further analyse the response of oat to osmotic stress, the level of phenolic compounds, soluble sugars, abscisic acid, and the activity of antioxidant enzymes were tested using spectrophotometric and chromatographic methods. During osmotic stress, the content of phenols, soluble sugars, abscisic acid, and the activity of catalase and peroxidase in shoots increased. In roots treated with PEG 6000, the amount of phenolic compounds was higher than that in roots treated with mannitol. The activity of superoxide dismutase was about 5‐fold higher in roots than in shoots. MTs are involved in plant response to osmotic stress. In the future, insight provided in this study will lead to application in agriculture either by using MTs as molecular markers for stress‐resistant crop cultivars or by a generation of genetically modified crops overexpressing MTs.

Multiscale Spectral Analysis on Lysozyme Aqueous Solutions in the Presence of PolyEthyleneGlycol.

Infrared spectroscopy measurements were performed on Lysozyme aqueous solutions also in the presence of PolyEthylene Glycol (PEG 400) as a function of an increasing temperature from T = 27 °C to 90 °C, and, successively in sequence, by decreasing temperatures from T = 90 °C to 27 °C. Data were analyzed by evaluating the spectral difference with respect to the initial spectrum collected at 27 °C. This procedure allows to quantitatively evaluate the thermal restraint related to the thermal scan from T = 27 °C to 90 °C, as well as to introduce a spectral resilience concerning the entire increasing and decreasing thermal paths which allow to highlight the bioprotectant effectiveness of low molecular weight PEG. In particular, the main purpose of the present work is to highlight the effects of a thermal treatment on a mixture of Lysozyme/water and of Lysozyme/water/PEG 400 during an increasing temperature scan, and then after a successive decreasing temperature scan, in order to highlight the bioprotectant role of PEG 400. On that score, an evaluation of the spectral distances of the registered spectra as a function of increasing and decreasing temperatures has been performed and analyzed.

Preferential precipitation of acidic variants from monoclonal antibody pools.

Microheterogeneity of monoclonal antibodies (mAbs) can impact their activity and stability. Formation of charge variants is considered as the most important source of the microheterogeneity. In particular, controlling the content of the acidic species is often of major importance for the production process and regulatory approval of therapeutic proteins.In this study, the preferential precipitation process was developed for reducing the content of acidic variants in mAb downstream pools. The process design was preceded by the determination of phase behavior of mAb variants in the presence of different precipitants. It was shown that the presence of polyethylene glycol (PEG) in protein solutions favored precipitation of acidic variants of mAbs. Precipitation yield was influenced by the variant composition in the mAb feed solutions, the concentration of the precipitant and the protein, and the ionic strength of the solutions. To improve yield, multistage precipitation was employed, where the precipitate was recycled to the precipitation process. The final product was a mixture of supernatants pooled together from the recycling steps.Such an approach can be potentially used either instead or in a combination with chromatography for adjusting the acidic variant content of mAbs, which can benefit in improvement in throughput and reduction in manufacturing costs.

In Vitro Gas Production Test: towards Rapid Nutritional Evaluation of Roughages for Ruminant Feeding

The gas production in vitro method was used to evaluate the degradability and gas production of browse plants in the absence or presence of polyethylene glycol 8,000 (PEG). Substrates (leguminous and browse plants; 500mg) were incubated for 24h and the accumulated gas produced recorded. The incubation contents of the syringes were transferred into nylon bags and the undegraded residues weighed after washing and drying to constant weight (SNB method). Substrates were also incubated in the rumen in nylon bags for 24 h to determine in sacco degradability. Gas production ranged between 10.3 to 64.4ml whereas the dry matter degradability ranges between 27.3 and 70.9%. Addition of PEG, which minimised the inhibitory effects of tannin on microbial fermentation resulted in an increase in both gas production and degradability in vitro, which ranged from 25.7 to 64.2 ml and 34.2 to 75.0%, respectively. Correlation analysis of the DM degradability estimated by the SNB method and in sacco method was better in presence of PEG (y= 0.71x + 14.9; r2 = 0.92) as compared to absence of PEG (y= 0.59x + 15.0; r2 = 0.72). Partitioning factor (PF) of substrate to gas, which was expressed as mg DM degraded/ml gas, reflects the variation in microbial biomass yield. The PF figures varied from 4.94 -11.05 to PF+PEG values of 4.74-6.84 upon the addition of PEG. The present study showed that presence of tannin has a potentially beneficial effect to protein nutrition of the host animal by altering partitioning of nutrients towards more microbial yield rather than short chain fatty acids. PF values of browse plants determined both on the absence and presence of PEG may indicate the relative importance of tannins in different plant species on substrate degradability and partitioning of nutrients.