alkaline enzymatic hydrolysis
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Poultry feathers make up for as much as 8.5% of chicken weight and represent a considerable amount of almost pure keratin waste which is not being adequately utilized at the present time. The present study dealt with the processing of poultry feathers through a two-stage alkaline-enzymatic hydrolysis. In the first stage, feathers were mixed with a 0.1 or 0.3% KOH water solution in a 1 : 50 ratio and were incubated at 70°C for 24 h. After adjusting pH to 9, the effects examined in the second processing stage on the amount of degraded feathers were those of proteolytic enzyme additions (1-5%), time (4-8 h) and temperature (50-70°C). Processing feathers in 0.3% KOH and hydrolysing for 8 h in the second stage at 70°C with a 5% dose of enzyme (relative to dry feathers weight) produced approx. 91% degradation. Keratin hydrolysate is distinct for its high nitrogen content and reasonable inorganic solids level. Two-stage technology of alkaline-enzymatic hydrolysing of poultry feathers in an environment of 0.3% KOH achieves high efficiency under quite mild reaction conditions (temperature not exceeding 70°C with pH in a mildly alkaline region), and is feasible from an economic viewpoint. Keratin hydrolysate can find particular application in packaging technology (films, foils and encapsulates).
- MeSH
- drůbež MeSH
- hydrolýza MeSH
- keratiny chemie MeSH
- koncentrace vodíkových iontů MeSH
- odpadky - odstraňování metody MeSH
- peří chemie MeSH
- proteasy chemie MeSH
- průmyslový odpad analýza statistika a číselné údaje MeSH
- teplota MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
This paper deals with the problem of chromium recovery from chrome-tanned waste and thus with reducing the environmental impact of the leather industry. Chrome-tanned waste was transformed by alkaline enzymatic hydrolysis promoted by magnesium oxide into practically chromium-free, commercially applicable collagen hydrolysate and filtration cake containing a high portion of chromium. The crude and magnesium-deprived chromium cakes were subjected to a process of thermal decomposition at 650°C under oxygen-free conditions to reduce the amount of this waste and to study the effect of magnesium removal on the resulting products. Oxygen-free conditions were applied in order to prevent the oxidation of trivalent chromium into the hazardous hexavalent form. Thermal decomposition products from both crude and magnesium-deprived chrome cakes were characterized by high chromium content over 50%, which occurred as eskolaite (Cr2O3) and magnesiochromite (MgCr2O4) crystal phases, respectively. Thermal decomposition decreased the amount of chrome cake dry feed by 90%. Based on the performed experiments, a scheme for the total control of chromium in the leather industry was designed.
An investigation was carried out using rice straw as a low-cost substrate to study the optimization of xylanase production using a newly identified endospore-forming bacterium, Bacillus altitudinis RS3025. The highest xylanase activity was achieved using 2% rice straw (pretreated with 2% NaOH at 100 °C) at pH 7.0, 37 °C temperature, and with 72-h incubation time. Under the optimized conditions, xylanase activity reached 2518.51 U/mL, which was 11.56-fold higher than the activity under the initial conditions using untreated rice straw as substrate. Enzymatic hydrolysis of the rice straw using crude xylanase of B. altitudinis RS3025 demonstrated the hydrolyzation efficiency of the rice straw waste, especially alkaline rice straw. The highest level of released reducing sugars was 149.78 mg/g substrate. The study demonstrated the successful utilization of rice straw waste for high-level xylanase production using B. altitudinis RS3025 and reducing sugar production using low-cost crude enzyme, which has the advantages of reducing the processing cost and environmental concerns associated with rice straw waste management.
- MeSH
- Bacillus * metabolismus MeSH
- celulasa * MeSH
- fermentace MeSH
- hydrolýza MeSH
- rýže (rod) * metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
Keratin hydrolysates (KHs) are established standard components in hair cosmetics. Understanding the moisturizing effects of KH is advantageous for skin-care cosmetics. The goals of the protocol are: (1) to process chicken feathers into KH by alkaline-enzymatic hydrolysis and purify it by dialysis, and (2) to test if adding KH into an ointment base (OB) increases hydration of the skin and improves skin barrier function by diminishing transepidermal water loss (TEWL). During alkaline-enzymatic hydrolysis feathers are first incubated at a higher temperature in an alkaline environment and then, under mild conditions, hydrolyzed with proteolytic enzyme. The solution of KH is dialyzed, vacuum dried, and milled to a fine powder. Cosmetic formulations comprising from oil in water emulsion (O/W) containing 2, 4, and 6 weight% of KH (based on the weight of the OB) are prepared. Testing the moisturizing properties of KH is carried out on 10 men and 10 women at time intervals of 1, 2, 3, 4, 24, and 48 h. Tested formulations are spread at degreased volar forearm sites. The skin hydration of stratum corneum (SC) is assessed by measuring capacitance of the skin, which is one of the most world-wide used and simple methods. TEWL is based on measuring the quantity of water transported per a defined area and period of time from the skin. Both methods are fully non-invasive. KH makes for an excellent occlusive; depending on the addition of KH into OB, it brings about a 30% reduction in TEWL after application. KH also functions as a humectant, as it binds water from the lower layers of the epidermis to the SC; at the optimum KH addition in the OB, up to 19% rise in hydration in men and 22% rise in women occurs.
A review of the current knowledge of the styrene and styrene oxide metabolism in laboratory animals and humans. Styrene ranks among the most important monomers in the manufacture of plastics and styrene oxide is the main intermediate involved in its metabolism. Both chemicals exhibit adverse effects. Various analytical methods have been developed for assessing their concentrations in organisms. Determination of their protein adducts shows several advantages over their determination in urine or as DNA adducts due to their stability and easy availability. The protein adduct determination by a modified Edman degradation, Raney-nickel cleavage, alkaline hydrolysis and enzymatic hydrolysis is described. Styrene oxide adducts with various globin amino acids have been also studied by these methods. A modified Edman degradation has proved to be a most sensitive method, with a limit of detection of the order of pmol per g of globin.
Passiflora species, mangosteen, and cherimoya peels are a source of bioactive phenolic compounds. Nevertheless, a significant fraction of polyphenols, called non-extractable polyphenols (NEPs), are retained in the extraction residue after a conventional extraction. Thus, alkaline, acid, and enzymatic-assisted extractions to recover high contents of antioxidant NEPs from the extraction residue of fruit peels, were compared in this work. A high-performance thin-layer chromatography method with UV/Vis detection was developed in order to obtain the phenolic profile for the extracts. The most intense bands were further analyzed by direct analysis in real-time-high-resolution mass spectrometry to tentatively identified NEPs in fruit peel extracts. Total phenolic and proanthocyanidin contents and antioxidant capacity of the extracts were measured to carry out a multivariate statistical analysis. Alkaline hydrolysis was the most efficient treatment to recover NEPs from fruit peels as well as a promising treatment to obtain antioxidant extracts along with EAE. Cherimoya peel extracts were the richest in antioxidant NEPs. This work highlights that many NEPs remain on the extraction residue of fruit peels after conventional extraction and are not usually taken into account.
