Purification and Characterization Laccase from Trametes versicolor (L.) Lloyd in Submerged Fermentation.

<b>Background and Objective:</b> Laccase is classified as an oxidoreductase enzyme that catalyzes oxidation reactions of phenolic groups by using oxygen as its electron acceptor. Laccase isolated from <i>Trametes versicolor</i> (L.) Lloyd has a wide range of applications in the industrial sector. The use of enzymes in the industrial sector requires pure enzyme conditions from impurities so that the enzyme can maximize its ability in converting the substrate. This study aims to obtain enzyme activity and the characteristic of purified laccase enzymes isolated from <i>Trametes versicolor</i> (L.) Lloyd. <b>Materials and Methods:</b> This study was conducted with an experimental method followed by descriptive analysis. The steps of this research consist of a qualitative assay of laccase enzyme, crude laccase extract desalting by Sephadex G-25, laccase purification by Sephadex G-100 and laccase optimum pH characterization. <b>Results:</b> The result of this study showed that purification of laccase from <i>Trametes versicolor </i>(L.) Lloyd with Sephadex G-25 increases laccase enzyme-specific activity which is 10.966 U mg¹ and reaches 2.93-fold purity. The highest laccase enzyme activity was achieved at pH 4 with a value of laccase activity 62.39 U L¹. <b>Conclusion:</b> Based on current results, purifying laccase from <i>Trametes versicolor </i>(L.) Lloyd with Sephadex G-25 was recommended which resulting higher enzyme specific activity.

Indigenous Bacteriocin of Lactic Acid Bacteria from "Dadih" a Fermented Buffalo Milk from West Sumatra, Indonesia as Chicken Meat Preservative.

BACKGROUND AND OBJECTIVE: The bacteriocin isolated from fermented buffalo milk from West Sumatra-Indonesia, called Dadih, can be considered as a natural and safe antimicrobial compound for food products. The objective of this research was to evaluate the antimicrobial activity of bacteriocin from Dadih and its effectiveness as a preservative in chicken meat. MATERIALS AND METHODS: This study used experimental method followed by statistical analysis using 3 experiments with duplication including experiment of meat samples (0 and 10% bacteriocin), storage temperatures (7 and 26°C) and storage duration (0, 1, 2, 3, 4, 5, 6 days and 0, 6, 12 hrs). Each experiment consists of a bacteriocin test, antimicrobial activity assay, physicochemical measurement and storability. RESULTS: From 10 LAB isolates successfully obtained from Dadih, two isolates with D7 code and D10 code had the highest antimicrobial activity, reaching 11.75 mm and 12 mm, respectively. The meat treated by 10% of bacteriocin gave the lower total microbial (3rd and 5th day) and total E. coli (5th day) at 7 and 26°C. The pH and water activity (aw) values of chicken meat with 10% of bacteriocin showed lower values at 7 and 26°C. The application of bacteriocin to chicken meat was able to inhibit the microbial growth that was still below standard for 3 days at 7°C and 6 hrs at 26°C. CONCLUSION: Based on research, lactic acid bacteria isolated from buffalo milk curd produced bacteriocin compound which has antimicrobial properties. This bacteriocin showed potential as a natural preservative for chicken meat by inhibiting the growth of pathogen microorganisms.

Study of Ganoderma lucidum in Laccase Production using Corncob and Paddies Straw Substrates on Submerged Fermentation System.

BACKGROUND AND OBJECTIVE: Ganoderma lucidum a white rot fungi, produce laccase which capable to degrade lignin due to its activity as ligninolytic enzymes. The production of laccase by G. lucidum using various agroindustrial wastes, including corncob and paddies straw, as substrates have been studied. The purpose of this study was to determine substrate that able to produce the highest activity of the laccase from the G. lucidum. MATERIALS AND METHODS: The method used an experimental design followed by descriptive analysis using 4 treatments with duplication including treatment G. lucidum growth into A (control, Potato Dextrose Broth (PDB)), B (PDB+corncob), C (PDB+rice straw) and D (PDB+corncob+rice straw). This study includes; (1) Qualitative assay determination of laccase, (2) Extraction and laccase activity, (3) Cell concentration of G. lucidum measurement and (4) pH measurement. RESULTS: Laccase qualitative assay showed brownish red ring on PDA media that indicated a positive of the laccase enzyme secreted by G. lucidum. Enzyme activity under submerged fermentation condition was achieved by the treatment of adding corncobs with the highest activity accounting 68.75 U mL-1. The fermentation process causes a decrease in pH during the incubation time to pH 4.83. The results of pH measurements showed that the laccase enzyme from G. lucidum worked optimally at pH 4-5 achieved after 5 day of incubation. CONCLUSION: Our results suggest that G. lucidum has potential to produce laccase enzyme by using substrate comprising corncob and rice straw on submerged fermentation.