Use Of Harsh Chemicals Research Articles

Catalyst-Free Microwave Digestion and Estimation of Nitrogen and Phosphorus Contents in Chicken Manure Adopting Competitive Analytical Methods

ABSTRACT For enhanced soil fertility, the application of animal manure has been recognized as an alternative mean to synthetic fertilizers. A major issue in current manure application practices is the rapid, reliable estimation of nutrients, such as nitrogen (N) and phosphorus (P). Estimation of N and P in manure involves the use of harsh chemicals and conditions, and considerable analytical time. In this work, microwave-assisted digestion condition is being reported for N and P estimation into chicken fermentation slurry. At comparative lower temperature 200°C and duration 1 h, digestion involves the use of half of the amount of acid and that too without the aid of a catalyst. Furthermore, N and P contents were determined from automatic Kjeldahl (AKj), manual Kjeldahl (MKj) and flow injection methods (FIA). The advantage of FIA is that it provides simultaneous detection of P and N. Additionally; P contents were analyzed and compared by colorimeter (Clr). To obtain a clear view of the performance of competing analytical procedures, a single sample analysis (SSA) time was measured. Thus, for N estimation; the SSA by AKj was superior, i.e.,, AKj ˃ MKj ˃ FIA which was 6:10:70 mins, respectively, and for P; Clr˃FIA which was 30:70 mins, respectively. However, when the adoptive methods were judged on the basis of effectiveness or by overall performance/ease in handling, the order of competing methods for N became AKj ˃ FIA ˃ MKj and for P it was FIA ˃ Clr. Statistical evaluations from the analytical data were also in accordance.

Fast decellularization process using supercritical carbon dioxide for trabecular bone

Decellularization is a process that consists on the removal of immunogenic cellular material from a tissue, so that it can be safely implanted as a functional and bioactive scaffold. Most decellularization protocols rely on the use of harsh chemicals and very long washing processes, leading to severe changes in the ultrastructure and loss of mechanical integrity. To tackle these challenges, supercritical carbon dioxide (scCO2) is herein proposed as an alternative methodology for assisting decellularization of porcine trabecular bone tissue and is combined, for the first time, with Tri(n-butyl) phosphate (TnBP). Histological and DNA analysis revealed that both TnBP and scCO2 were able to extract the DNA content from the scaffolds, being this effect more pronounced in treatments that used TnBP as a co-solvent. The combined protocol led to a decrease in DNA content by at least 90%, demonstrating the potential of this methodology and opening new possibilities for future optimizations.

Native-like Flow Properties of an Artificial Spider Silk Dope.

Recombinant spider silk has emerged as a biomaterial that can circumvent problems associated with synthetic and naturally derived polymers, while still fulfilling the potential of the native material. The artificial spider silk protein NT2RepCT can be produced and spun into fibers without the use of harsh chemicals and here we evaluate key properties of NT2RepCT dope at native-like concentrations. We show that NT2RepCT recapitulates not only the overall secondary structure content of a native silk dope but also emulates its viscoelastic rheological properties. We propose that these properties are key to biomimetic spinning and that optimization of rheological properties could facilitate successful spinning of artificial dopes into fibers.

High osmotic stress initiates expansion and detachment of Thalassospira sp. biofilms in glass microchannels

Control of microbial activity and biofilm growth is an essential factor in a variety of medical and industrial applications. As microbial biofilms can protect cells within from physical or chemical threats, biocide treatments are often limited in their efficiency due to the low permeability of the biofilm. Therefore, finding new treatment options against biofilms remains an issue of high importance. We explored the option of using osmotic pressure to physically deform the biofilm matrix and increase detachment from a glass surface. Our model system is a single-species biofilm of Thalassospira sp. growing in a microfluidic set-up, enabling the observation of changes in biofilm volume and detachment rate. We observed that injection of a high salinity brine (NaCl) led to a reduction of biofilm volume (water efflux), and that subsequent injection of low salinity brine caused biofilm expansion (water influx). The differential osmotic pressure imposed on the biofilm was sufficient to weaken its adhesive strength to the glass surface, causing major detachment. The current approach has value as a method for cleaning glass microfluidic channels and other glass tubing or equipment clogged by biofilms, thus avoiding the use of harsh chemicals. As the basic physical principle of osmotic pressure initiating biofilm expansion and detachment is universal, our findings could be applied to other forms of biofilm growth.

UHPLC-LTQ OrbiTrap MS analysis and biological properties of Origanum vulgare subsp. viridulum obtained by different extraction methods

The growing awareness on implications related to the use of harsh chemicals and non-sustainable extraction methods of bioactive compounds from plants is causing a paradigm shift towards a more eco-friendly approach. The present study sets out to investigate the possible variation in the antioxidant, mutagenic/antimutagenic, antimicrobial, and enzyme inhibitory properties of Origanum vulgare subsp. viridulum extracts obtained using conventional, namely, maceration and Soxhlet extraction, and non-conventional, namely, ultrasound-assisted (UAE), microwave-assisted (MAE), and accelerated solvent extraction (ASE), techniques. Also, chemical characterization of these extracts were performed via ultrahigh-performance liquid chromatography and mass spectrometry (UHPLC-LTQ OrbiTrap MS) technique. A total of 58 polyphenols were identified in the tested extracts. Highest phenolic content was obtained from ASE (186.63 mg gallic acid equivalent [GAE]/g) and MAE (170.90 mg GAE/g) extracts. Maceration extract (18.89 mg rutin equivalent [RE]/g) showed highest flavonoid content. ASE extract showed highest activity in the DPPH (359.45 mg Trolox equivalent [TE]/g), ABTS (679.63 mg TE/g), FRAP (1433.94 mg TE/g), and CUPRAC (1685.72 mg TE/g) assays. In terms of enzyme inhibition, the UAE extract showed highest activity against acetyl cholinesterase (4.55 mg galantamine equivalent [GALAE]/g), butyryl cholinesterase (6.12 mg GALAE/g), and tyrosinase (173.87 mg kojic acid equivalent [KAE]/g) compared with the other extracts. The extracts exhibited significant antimutagenic and antimicrobial properties. Data collected from this study support the use of ASE and UAE in the extraction of bioactive compounds from Origanum vulgare subsp. viridulum aerial parts.

Chemistry and Mechanism of One-Step Formation of Graphene from Agrowaste

The one-step synthesis of high-quality graphene derivatives via CVD process has gained considerable importance nowadays for high-performance electronics and sensors. However, the use of harsh chemicals, high temperature, sensitivity, and the problem of separation of graphene from the substrate, motivated the one-step synthesis of graphene from a non-graphitic precursor, bypassing the use of graphite. In this paper, we have reported for the first time, the synthesis of graphene nanosheets from sugarcane bagasse at the normal atmospheric condition in a single step, avoiding the formation of GO. Here, the pyrolysis of sugarcane bagasse was carried out in the temperature range of 250-450o C in the presence of sodium hydroxide. The results suggested that even the low temperature (250–450o C) facilitated the development of graphitic planes via condensation and aromatization of the glucose monomers present in the precursor. The XRD pattern showed 2θ at around 25o in each case, which confirmed the formation of graphene instead of GO. The FESEM, TEM, and EDX analysis proved the formation of few-layer nanosheets of graphene from carbon-rich waste precursors in a single step.

Stimuli-Responsive Membranes through Sustainable Aqueous Phase Separation.

Polymeric membranes are used on huge scales for kidney dialysis, wastewater treatment, and drinking water production. However, almost all polymeric membranes are fabricated by a process reliant on the use of unsustainable, expensive, and reprotoxic dipolar aprotic solvents. In this work, we propose an aqueous phase separation approach for preparing porous membrane films. Poly(4-vinylpyridine) (P4VP), a pH-responsive polymer, is first dissolved at low pH where the polymer is charged and subsequently cast as a thin film. Switching to a high pH where the polymer is uncharged and insoluble results in controlled phase separation and solidification of the polymer into porous membrane structures. This approach gives a large degree of control over membrane structure, leading to symmetric porous microfiltration membranes and asymmetric dense nanofiltration membranes. Moreover, the use of a pH-responsive polymer leads directly to a pH-responsive membrane, where the degree of responsive behavior can be tuned by the degree of cross-linking. Such responsive behavior allows effective cleaning of the membrane, without the use of harsh chemicals. This work outlines an approach toward preparing membranes in a more sustainable fashion—an approach that allows control over the membrane structure and one that naturally leads to advanced membranes with responsive properties.

α-Chymotrypsin catalysed oligopeptide synthesis for hair modelling

Abstract Conventional chemical treatments imply the use of harsh chemicals which can cause serious adverse effects on consumers’ health, hair fibre and environment. In this work was reported for the first time the modelling shape of Asian hair by oligopeptide coating synthesized by a protease. α-Chymotrypsin from Bovine pancreas catalysed the oligomerization of the tri-peptides, KCL (Lysine-Cysteine-Leucine) ethyl ester and KSL (Lysine-Serine-Leucine) ethyl ester in aqueous media. The synthesis reaction gave rise to oligopeptides with DP = 6, which were characterized by mass spectra (MALDI-TOF). The in situ synthesis reaction onto the hair surface, under controlled pH (8.5–9) and temperatures between 25 °C and 55 °C, formed a coating layer inducing changes in the hair shape from straight to curly. Qualitative and quantitative characterization of coated hair was performed by image visualization and by perming efficiency assessment. The developed strategy revealed to be a safer and cleaner alternative to the conventional chemical treatments generally used for hair shape modification. Low cost associated to the catalyst and lower side effects to the hair fibre, health consumer and environment might lead to the development of a cost-effective and sustainable approach in the hair care industry.

Material Design Advancement Create Multifunctional Materials for Single-Layer Bonding and Debonding

Multifunctional materials are a relatively new topic in the semiconductor industry for wafer-level packaging (WLP). With the increase in processing steps and the emergence of more advanced technologies, the use of multifunctional materials will become a more integral part in the future of temporary bonding and debonding (TB/DB) as well as other advanced packaging applications. One approach to multifunctional material design incorporates adhesive and laser release attributes in one material layer. Although this is similar to a thermal release material, it has greater thermal capabilities due to its ability to be cured and undergo laser debond. Many advantages may be obtained by combining a curable adhesive and laser release layer into one material. One of the greatest advantages is the reduction in overall processing time and steps required to bond wafer pairs as well as the reduction of chemical waste, due to the use of one material compared to two or more materials which significantly reduces the cost of ownership. Curable adhesive single layer systems offer access to higher temperatures with less material flow from the curable layer, strong adhesion for high stress applications where wafers can delaminate or spontaneously debond when using multilayer mechanically debonding systems such as Fan-Out Wafer Level Packaging (FOWLP), and offer lower wafer stress and warpage due to fewer material interfaces within the bonded wafer pairs causing less potential mismatch of materials coefficient of thermal expansion(CTE). Some challenges with this concept stem from the concern of the cleanability of a curable layer and potential laser damage to the device. In order to wet clean a curable layer, which is usually very solvent resistant due to the crosslinked nature, requires harsh solvent based solutions (that may contain either strong acid or base, require long cleaning time, and high temperature). This study will address all of the aforementioned challenges and includes the developmental advancements in material designs that resulted in the creation of new multifunctional materials. These multifunctional materials have been designed to be thermally curable, prevent material reflow of the bonding layer at higher temperatures, while still remaining wet cleanable without the use of harsh chemicals and long times. As with any material that utilize laser release methods there are concerns about device damage from laser energy penetrating to the device but multifunctional materials address this in two ways: they offer high absorbance of the laser energy at all commercially available laser tool wavelengths and they can be utilized as a thicker film as they act as the bonding layer as well. By overcoming their challenges, they will minimize the cost of ownership while driving advancement in future materials and processing.

Controlled volume production of simultaneously B/N co-doped reduced graphene oxide nanoflakes using femtosecond laser ablation

B and N co-doped reduced graphene oxide (B/N-rGO) nanoflakes were produced from a mixed aqueous solution of graphene oxide nanoflakes and boron nitride quantum dots, using high intensity femtosecond laser ablation. We observed a controlled production of B/N-rGO nanoflakes with an average flake size of 2.3 μm to 2.7 μm, with up to 5.9 at% boron and 4.1 at% nitrogen co-doping. The B/N-rGO nanoflakes were obtained in as low as 30 min, at ambient room temperature, and without the use of harsh chemicals.

Coding cell micropatterns through peptide inkjet printing for arbitrary biomineralized architectures.

Well-designed micropatterns present in native tissues and organs involve changes in extracellular matrix compositions, cell types and mechanical properties to reflect complex biological functions. However, the design and fabrication of these micropatterns in vitro to meet task-specific biomedical applications remains a challenge. A de novo design strategy to code and synthesize functional micropatterns is presented to engineer cell alignment through the integration of aqueous-peptide inkjet printing and site-specific biomineralization. The inkjet printing provides direct writing of macroscopic biosilica selective peptide-R5 patterns with micrometer-scale resolution on the surface of a biopolymer (silk) hydrogel. This is combined with in situ biomineralization of the R5 peptide for site-specific growth of silica nanoparticles on the micropatterns, avoiding the use of harsh chemicals or complex processing. The functional micropatterned systems are used to align human mesenchymal stem cells and bovine serum albumin. This combination of peptide printing and site-specific biomineralization provides a new route for developing cost-effective micropatterns, with implications for broader materials designs. Coding cell micropatterns through peptide inkjet printing for arbitrary biomineralized architectures is demonstrated here. The functional micropatterned systems are used to align human mesenchymal stem cells and bovine serum albumin in vitro, avoiding the use of harsh chemicals or complex processing, while providing potential applications in developing cost-effective micropatterns to meet task-specific biomedical applications.

EFFECT OF SILVER NANOPARTICLE-MEDIATED WOUND THERAPY ON BIOCHEMICAL, HEMATOLOGICAL, AND HISTOLOGICAL PARAMETERS

Objective: Green synthesis of nanoparticles has been used as an alternative, efficient, less expensive, and ecofriendly method. Ancient approaches employed for nanoparticle fabrication were chemical and physical methods having various disadvantages as they are costly and potentially harmful to the environment, use of harsh chemicals and stringent protocol for synthesizing nanoparticles. The present study is focused on the synthesis of silver nanoparticles by bio-availed as well as chemical route and evaluation of their wound healing potential in Wistar rat model.Methods: Extraction of Syzygium cumini was done and was used for silver nanoparticle synthesis. The synthesized nanoparticles were characterized by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy, which confirms the availability of nanosilver particles with marginally spherical morphology. The particles were then carried forward for treating impaired diabetic wounds in Wistar rat models. Regular photography was done and wound healing parameters were monitored throughout the study along with analyzing other parameters such as biochemical, hematological, and histological parameters.Results: The study showed that the sizes of the synthesized nanoparticles are below 100 nm. The results obtained from in vivo studies showed efficient wound healing potential of silver nanoparticles as compared to pre-existing drug povidone-iodine, i.e., the percentage reduction in wound area after therapy is 96.09% in case of biosynthesized silver nanoparticle-treated group, 97.7% reduction in chemically synthesized silver nanoparticle-treated group, 64.28% reduction in case of pre-existing drug povidone-iodine-treated group, 37.5% reduction in case of diabetic control group (diabetic), and 97.5% reduction in normal control group (non-diabetic). Results showed that biosynthesized silver nanoparticles showed less toxicity with respect to liver and kidney functions. Skin histology results showed increased sign of wound healing in biosynthesized silver nanoparticles. Hematology results showed no such variation.Conclusion: The study will help to synthesize new economically viable potential biosynthesized nanoparticles along with providing the approach to develop the medication at nanoscale level.

Green Preparation of Cellulose Nanocrystal and Its Application

A green method was used to prepare cellulose nanocrystals (CNCs) with no use of harsh chemicals or organic solvents. This method was simple via ball milling cellulose with water followed by centrifugation. The diameter and length of the CNCs were 3–10 nm and 120–400 nm, separately, with a aspect ratio of 20–60. The yield was about 20%. The thermal stability of the CNCs was the same as that of raw cellulose owing to lacking of chemical modification. So it was superior to CNCs prepared by acid hydrolysis. Then poly(vinyl alcohol) (PVA)/CNC composite film was made by solution casting. The results showed that the tensile strength of the composite film was 79% increased from neat PVA film when adding 5% CNCs to the PVA matrix. In addition, the composite films possessed good transparency and thermal stability.

Encapsulation of Bioactive Compound in Electrospun Fibers and Its Potential Application

Electrospinning is a simple and versatile encapsulation technology. Since electrospinning does not involve severe conditions of temperature or pressure or the use of harsh chemicals, it has great potential for effectively entrapping and delivering bioactive compounds. Recently, electrospinning has been used in the food industry to encapsulate bioactive compounds into different biopolymers (carbohydrates and proteins), protecting them from adverse environmental conditions, maintaining the health-promoting properties, and achieving their controlled release. Electrospinning opens a new horizon in food technology with possible commercialization in the near future. This review summarizes the principles and the types of electrospinning processes. The electrospinning of biopolymers and their application in encapsulating of bioactive compounds are highlighted. The existing scope, limitations, and future prospects of electrospinning bioactive compounds are also presented.

Rapid Nucleic Acid Extraction and Purification Using a Miniature Ultrasonic Technique.

Miniature ultrasonic lysis for biological sample preparation is a promising technique for efficient and rapid extraction of nucleic acids and proteins from a wide variety of biological sources. Acoustic methods achieve rapid, unbiased, and efficacious disruption of cellular membranes while avoiding the use of harsh chemicals and enzymes, which interfere with detection assays. In this work, a miniature acoustic nucleic acid extraction system is presented. Using a miniature bulk acoustic wave (BAW) transducer array based on 36° Y-cut lithium niobate, acoustic waves were coupled into disposable laminate-based microfluidic cartridges. To verify the lysing effectiveness, the amount of liberated ATP and the cell viability were measured and compared to untreated samples. The relationship between input power, energy dose, flow-rate, and lysing efficiency were determined. DNA was purified on-chip using three approaches implemented in the cartridges: a silica-based sol-gel silica-bead filled microchannel, nucleic acid binding magnetic beads, and Nafion-coated electrodes. Using E. coli, the lysing dose defined as ATP released per joule was 2.2× greater, releasing 6.1× more ATP for the miniature BAW array compared to a bench-top acoustic lysis system. An electric field-based nucleic acid purification approach using Nafion films yielded an extraction efficiency of 69.2% in 10 min for 50 µL samples.

Pre-treatment of biomasses using magnetised sulfonic acid catalysts

There is a significant interest in employing solid acid catalysts for pre-treatment of biomasses for subsequent hydrolysis into sugars, because solid acid catalysts facilitate reusability, high activity, and easier separation. Hence the present research investigated pretreatment of four lignocellulosic biomasses, namely Switchgrass (Panicum virgatum L ‘Alamo’), Gamagrass (Tripsacum dactyloides), Miscanthus (Miscanthus × giganteus) and Triticale hay (Triticale hexaploide Lart.) at 90°C for 2 h using three carbon-supported sulfonic acid catalysts. The catalysts were synthesized via impregnating p-Toluenesulfonic acid on carbon (regular) and further impregnated with iron nitrate via two methods to obtain magnetic A and magnetic B catalysts. When tested as pre-treatment agents, a maximum total lignin reduction of 17.73±0.63% was observed for Triticale hay treated with magnetic A catalyst. Furthermore, maximum glucose yield after enzymatic hydrolysis was observed to be 203.47±5.09 mg g–1 (conversion of 65.07±1.63%) from Switchgrass treated with magnetic A catalyst. When reusability of magnetised catalysts were tested, it was observed that magnetic A catalyst was consistent for Gamagrass, Miscanthus × Giganteus and Triticale hay, while magnetic B catalyst was found to maintain consistent yield for switchgrass feedstock. Our results suggested that magnetised solid acid catalyst could pre-treat various biomass stocks and also can potentially reduce the use of harsh chemicals and make bioenergy processes environment friendly.

Efficient Pt electrocatalysts supported onto flavin mononucleotide–exfoliated pristine graphene for the methanol oxidation reaction

Due to its large surface area, high electrical conductivity as well as mechanical and thermal stability, pristine graphene has the potential to be an excellent support for metal nanoparticles (NPs), but the scarce amount of intrinsic chemical groups/defects in its structure that could act as anchoring sites for the NPs hinders this type of use. Here, a simple strategy based on the stabilization of pristine graphene in aqueous dispersion with the assistance of a low amount of flavin mononucleotide (FMN) is shown to yield a material that combines high electrical conductivity and abundance of extrinsic anchoring sites, so that pristine graphene–metal (Pd and Pt) NP hybrids with good dispersion and metal loading can be obtained from FMN–stabilized graphene. The activity of these hybrids towards the methanol oxidation reaction (MOR) both in acidic and alkaline media is studied by cyclic voltammetry (CV) and their stability investigated by chronoamperometry. The pristine graphene–Pt NP hybrid prepared by this simple, eco–friendly protocol is demonstrated to outperform most previously reported pristine graphene– and reduced graphene oxide–metal NP hybrids as electrocatalyst for the MOR, both in terms of catalytic activity and stability, avoiding at the same time the use of harsh chemicals or complex synthetic routes.

Towards timely Alzheimer diagnosis: A self-powered amperometric biosensor for the neurotransmitter acetylcholine

Serious brain disorders, such as the Alzheimer's Disease (AD), are associated with a marked drop in the levels of important neurotransmitters, such as acetylcholine (ACh). Real time monitoring of such biomarkers can therefore play a critical role in enhancing AD therapies by allowing timely diagnosis, verifications of treatment effectiveness, and developments of new medicines. In this study, we present the first acetylcholine/oxygen hybrid enzymatic fuel cell for the self-powered on site detection of ACh in plasma, which is based on the combination of an enzymatic anode with a Pt cathode. Firstly, an effective acetylcholinesterase immobilized electrode was developed and its electrochemical performance evaluated. Highly porous gold was used as the electrode material, and the enzyme was immobilized via a one step rapid and simple procedure that does not require the use of harsh chemicals or any electrode/enzyme pre-treatments. The resulting enzymatic electrode was subsequently used as the anode of a miniature flow-through membrane-less fuel cell and showed excellent response to varying concentrations of ACh. The peak power generated by the fuel cell was 4nW at a voltage of 260mV and with a current density of 9μAcm−2. The limit of detection of the fuel cell sensor was 10μM, with an average response time as short as 3min. These exciting results open new horizons for point-of-care Alzheimer diagnosis and provide an attractive potential alternative to established methods that require laborious and time-consuming sample treatments and expensive instruments.

Abstract 369: Automating recovery of spiked tumor cells from blood

Abstract The isolation and study of circulating tumor cells (CTC) enables personalized medicine solutions, monitoring of therapeutics (theragnostics), and monitoring of minimal residual disease (MRD); culturing these rare cells is a frequent goal in cancer research, however the common methods for their isolation (gradient centrifugation, lysis buffer) are damaging to these cells, and many emerging technologies leave the cells bound in a consumable, bound to a biomarker or in a state that is difficult to use in cell culture. Further, the anuclear cells in blood greatly outnumber nucleated cells and present significant challenges to the study of the nucleated cells, for example, erythrocytes can absorb excitation or emission wavelengths in fluorescence studies, and their shape promotes rouleaux formation which can sequester the cells of interest; platelets also have a tendency to be activated by physical handling and cause aggregation that can also sequester and damage the cells of interest, and these all contain the greatest content of RNA and other markers that increase background noise in many assays. We demonstrate a new technology that automates the depletion of erythrocytes, thrombocytes, and plasma markers from, initially, small volumes of blood, using a micromachined membrane filter. We spiked small counts (10 to 1000 estimated from dilution) of tumor cell lines BT474 (breast cancer), DLD1 (colorectal cancer), and K562 (myelogenous leukemia) and other cell types into aliquots of blood. Using calcein-AM-loading to distinguish the spiked cells from blood cells, the recovery rates were determined in a flow cytometer, indicating an average of 80% ±4% (SE, N = 27) recovery of the rare cells after depletion of anuclear cells and plasma. The technology is amenable to use of beads for initial negative depletion of common nucleated cells by magnetic beads and has a recovery capacity of a few to as much as 3 million cells per specimen. Tumor cell lines alone that were run through this automation process then seeded for cell culture demonstrated growth rates indistinguishable from those seeded in similar counts in a regular cell passage. In further studies we demonstrate depletion of leukocytes with magnetic beads and of anuclear cells by filtration to handle larger blood volumes. The filtration system may be used for automated recovery of nucleated cells or cell clusters from blood or other fluid samples (liquid biopsies) without use of harsh chemicals or centrifugation, removing a common barrier for emerging analytical approaches. Citation Format: Mark Sarinana, Ky Truong, Keith Cannon, Antonio Guia. Automating recovery of spiked tumor cells from blood. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 369.

Development of an Alternative Enzyme-assisted Dehairing Method of Animal Skins using Proteases from Bacillus licheniformis MZK05M9

The present study was aimed to develop an enzyme assisted dehairing method as an alternative and ecofriendly technique to reduce the use of harsh chemicals in leather manufacturing. For this purpose, two proteases namely alkaline protease (601 U/ml) and keratinase (132 U/ml) were produced by Bacillus licheniformis MZK05M9 (BlM9) in Soya molasses medium and Feather mill medium respectively, in 7.0 L bioreactor at pH 7.5 and 37°C. The cell free enzyme preparations were used together at 2.5% level in dehairing experiments. Three sets of experiments for dehairing of goat skins were performed with (1) enzymes; (2) enzymes and 5% lime (CaO) and (3) 2% sodium sulfide (Na2S) and 5% lime. The treatment with enzymes removed 85% of hair from goat skin after 24 hrs under mild shaking condition at room temperature where as the treatment with enzymes and 5% lime together resulted in 100% dehairing under similar conditions. Sodium sulfide along with lime also removed 100% hair faster (with 20 hrs) than other two treatments. The grain surface of the enzyme treated skin was smoother and silkier than that of the chemicals treatment as revealed by Scanning Electron Microscopy. Thus these results indicated that, the enzyme assisted method can be applied in largescale dehairing trial to reduce the use of harsh sodium sulfide.Bangladesh J Microbiol, Volume 32, Number 1-2,June-Dec 2015, pp 33-37