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Production, purification and characterization of chitinase from Micromonospora sp. AR17
No full textN‐acetylglucosamine (NAG) is the monomer product of chitin, which has been widely used as a bioactive com‐ pound in applications such as anti‐tumor, anti‐microbial, and antioxidant activities. In production, biological processes using enzymes are preferable to chemicals due to environmental issues. This study aims to determine the activity, purity level, and molecular weight of purified chitinase from Micromonospora sp. AR17 determines the concentration of NAG produced by purified chitinase that has been characterized. Chitinase was produced by fermentation in colloidal chitin broth at 40 °C, pH 7, for 7 days, while chitinase activity was checked every 24 h. The optimal fermentation time was used to produce chitinase for a further purification step. Enzyme purification was carried out by ultrafiltration, ammonium sulfate precipitation, ion exchange chromatography (Q Sepharose Fast Flow), and gel filtration (Sephacryl S‐300). The purified enzyme was then char‐ acterized for optimum time, pH, and temperature to produce NAG. The results suggested that the fourth day was the optimal time for chitinase production, with chitinase activity of 0.0040 U/mL and a NAG concentration of 7.62 µg/mL. The purifica‐ tion step successfully increased the purity by 6.82 times with chitinase‐specific activity at 1.4648 U/mg. Production of NAG with purified chitinase produced a NAG concentration of 32.472 µg/mL with an incubation time of 30 min at 40 °C and pH 7.</jats:p
ISOLASI DAN PEMANFAATAN BAKTERI PROTEOLITIK UNTUK MEMPERBAIKI KUALITAS LIMBAH CAIR PENGOLAHAN BANDENG PRESTO (Isolation and Utilization of Proteolytic Bacteria to Improve The Quality of Milkfish Presto Processing Wastewate)
Get PDFABSTRAK
Industri pengolahan ikan menghasilkan limbah dengan kadar protein tinggi. Penambahan bakteri proteolitik diharapkan dapat membantu mendegradasi limbah berprotein tinggi. Pada penelitian ini, isolasi bakteri proteolitik dilakukan untuk mendapatkan isolat dengan aktivitas proteolitik tinggi. Isolat terbaik diuji kemampuan hidup dan aktivitasnya pada berbagai konsentrasi NaCl dan pH. Kemampuan isolat meningkatkan kualitas limbah juga diuji pada limbah pengolahan bandeng presto. Hasil penelitian diperoleh 36 isolat bakteri proteolitik dari limbah cair pencucian ikan Pasar Kranggan Yogyakarta. Dari ke-36 isolat tersebut, isolat D61 merupakan isolat dengan aktivitas proteolitik tertinggi dengan zone diameter 20,5 mm. Isolat tersebut mampu hidup pada NaCl 0-10% dan kisaran pH 5-10, namun aktivitas proteolitik tertingginya pada NaCl 0-2% dan kisaran pH 7-8 dan pH 10. Berdasarkan karakteristik morfologi dan biokimianya, isolate D61 memiliki kemiripan 93,93% dengan Bacillus soli. Hasil ujicoba pada limbah cair pengolahan bandeng presto ternyata isolat D61 tidak mampu memperbaiki kualitas limbah tersebut.
ABSTRACT
In this research, isolation of proteolytic bacteria was performed to obtain isolates with high proteolytic activity based on their ability to degrade the protein. The best isolate was examined for their growth ability and proteolytic activity in different concentrations of NaCl and degree of acidity (pH). Furthermore, the isolate ability to improve wastewater quality was observed in milkfish presto processing wastewater. Thirty-six proteolytic bacteria were isolated from fish washing wastewater of Kranggan Market, Yogyakarta. Isolate D61 has the highest proteolytic activity with activity about 20,5 mm. Isolate D61 was able to grow at a concentration of 0-10% NaCl with the highest proteolytic activity at the concentration of 0-2% NaCl. Isolate D61 was also able to live at pH 5-10 with the highest proteolytic activity at pH 7-8 and pH 10. Based on morphology and biochemical characteristics, D61 has 93.93% similarity with Bacillus soli. However, isolate D61 was not able to improve the quality of milkfish presto processing wastewater
Optimization of chitinase production from bacillus cereus smg 1.1 using response surface methodology
No full textShrimp shell waste are potential to be processed further into value-added products, such as N-acetylglucosamine (GlcNAc). In the production of GlcNAc, biological approach is preferred and environmentally friendly to chemical treatment. Chitinase is an enzyme that plays a vital role in bioprocessing of shrimp shell waste into GlcNAc. Previously, Bacillus cereus SMG 1.1 was isolated from fermented shrimp paste (terasi) and showed the ability to produce chitinase. This study was designed to determine the optimum medium for the production of chitinase from B. cereus SMG 1.1 through the Response Surface Method (RSM) using a factorial design with 15 treatments. The optimization of the media was carried out by determining the factors that influence the production of chitinase through the Plackett-Burman design followed by optimization of the concentration of the media through the Box-Behnken design. The test was designed to assess the effect of the independent variables on chitinase activity. Placket Burman analysis shows that colloidal chitin, fructose, and MgSO4.5H2O were the significant components in the medium affecting the production of chitinase by B. cereus SMG 1.1. Box-Behnken analysis developed a linear model capable of predicting the response. The highest response value was achieved at a concentration of 0.75% fructose, 1.5% colloidal chitin, and 0.075% MgSO4.5H2O resulted in optimum chitinase activity of 0.0016 U/ml
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Penyiapan Starter Kering Bakteri Asam Laktat Halofilik untuk Pengolahan Hasil Perikanan Fermentatif Bergaram
No full textLactic acid bacteria (LAB) is known as fermentation agent in traditional food fermentation products in Indonesia, which also include fish products. Objectives of this research were to select LAB strain isolated from peda, terasi, salted fish and bekasam which were potential for dry starter preparation. This research were consisted of three parts : (a) selection of halophilic LAB strain (b) dry starter preparation by addition glycerol protectant, sucrose and starter neutralization and further testing its viability upon storage and (c) ability of the selected isolate to inhibit pathogenic and spoilage bacteria. Results of this reseacrh indicated there were 8 moderate halophilic LAB, they were Lb. plantarum (isolate EDI-14, DES-21, DES-24, and DES-26), Leuc. paramesenteroides (isolate DAN-7 and DAN-7), and Lv. casei subsp. casei (isolateDES-27). Addition of 5% glycerol protects LAB viability during storage. Addition of 17.7% sucrose in the media and neutralized the pH increase LAB viability during storage. Within 5 weeks of storage. The viability of Leuc. paramesenteroides (DAN-7) and Lb. plantarum (DES-26) decrease 10.4% (from 33 x 107 sel/g to 3.3 x 107 sel/g dried starter) and 9.77% (from 36 x 107 sel/g to 3.5 x 107 sel/g dried starter), respectively. Freeze drying process and dry storage did not affect the LAB isolate towards inhibiting the pathogenic bacteria and spoilage bacteria such as Salmonella choleraesius JCM 3919, Shigella, Escherichia coli FNCC 0091, Vibrio parahaemolyticus JCM 2147 (gram negative), Staphylococcus aureus FNCC 0091, and Morganella morganii NCTC 2847 (gram positive)
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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