Isolation and Identification of Lignolytic Enzymes Producing Microorganisms from Aquatic Environments and Media Optimization for Biodegredation of Industrial Pollutants
Project no. 438 · Status: Kapanmış · 2017
Summary
In this thesis, production of lignolytic enzymes from actinobacteria and fungi isolated from aquatic systems were investigated qualitatively and quantitatively and the medium optimization was carried out by the orthogonal matrix method. The isolate which had the highest laccase activity was selected and color removal of industrial dyes with different chemical structures was measured spectrophotometrically. Qualitative screenings were performed using 2,2'-azinobis-3-ethylbutiazoline-6-sulphonate (ABTS), guaiacol and Remazol Brilliant Blue-R (RBBR) indicator compounds in Starch yeast extract agar, Soy glycerol agar, Boyd & Kohlmeyer agar, Malt extract agar media. The measurement of laccase activity was determined according to ABTS oxidation in Starch yeast extract and Soy glycerol liquid media. Ligninolytic enzyme activity was not determined in actinobacteria, whereas it was detected in six marine derived fungi. Molecular identification of the isolates were performed by determining the partial region of 18S rRNA gene, the complete regions of ITS1, 5.8S rRNA gene, ITS2 and the partial region of the 28S rRNA gene by using NSI1 and NLB4 primers. The highest laccase activity and the day of the highest activity of identified ligninolytic marine derived fungi were as follows: Alternaria sp. isolate D11 (Accession no: MH029119) 6th day 29 U/L, Alternaria sp. isolate D21 (Accession no: MH029120) 5th day 60.0 U/L, Cadophora sp. isolate D43 (Accession no: MH029121) 4th day 1.8 U/L, Cadophora luteo-olivacea isolate D51 (Accession no: MH029122) 7th day 0.54 U/L, Phoma sp. isolate K2BR (Accession no: MH029123) 5th day 32.0 U/L, Phoma sp. isolate K21 (Accession no: MH029124) 4th day 30.5 U/L. The isolate (Alternaria sp. isolate D21) with the highest laccase activity has been selected for decolorization studies of industrial dyes with different chemical structures. Decolorization ratios on industrial dyes of the isolate of which laccase activity was measured as 65 U/L in an optimized medium (after 144 hours) were detected as 98% for methyl orange, 93% for acid green 3, 78% for methylene blue, 71% for Remazol Brilliant Blue R, 58% for Crystal violet, and 53% for Congo red. Alternaria sp. isolate D21 (Accession no: MH029120) which showed a significant decolorization success, is important for further enzyme and bioengineering investigations and it should be integrated to these fields. Further studies should be increased and developed for fast and economic color removal of industrial wastes, such as marine and related aquatic systems contaminated with dyes. Key words: Lignolytic enzyme, laccase, marine-derived fungi, decolorization