Induction and enhancement of the novel marine-derived Alternaria tenuissima KM651985 laccase enzyme using response surface methodology: Application to Azo and Triphenylmethane dyes decolorization.

In our search for a laccase producer from unconventional sources, the marine derived fungus Alternaria tenuissima KM651985 was isolated from decayed wood. It was identified on the basis of morphological and molecular taxonomy and got the Genbank accession number KM651985. Two statistical experimental designs were employed to enhance laccase production. At first, a two level Plackett-Burman design was employed to screen the medium constituents and inducers that significantly affect the enzyme production. Second experiment was important for optimization of the most effective constituents and inducers using central composite design. Applying the above methods revealed that guaiacol (2 mM), copper sulphate (3 mM) and wheat bran (46.82 g/l) were the most effective factors affecting laccase production. A maximal enzyme activity of 91.84 U/ml was more than 6.33-folds the activity obtained using the basal medium. Application of A. tenuissima KM651985 culture medium containing laccase to decolorize two structurally different synthetic dyes was done successfully. This is the first report on the statistical optimization of the marine-derived A. tenuissima KM651985 laccase enzyme and its applications for dyes decolorization.

Trichoderma asperellum isolated from salinity soil using rice straw waste as biocontrol agent for cowpea plant pathogens.

This study discusses isolation and identification new fungal isolate from salinity soil for controlling soil borne diseases. Among sixteen fungal, a potent isolate coded SRBP_ZSHSG1 was isolated from Sugar beet rhizospher samples collected from Al-Hosainia localities-El-Sharkia-Egypt. Traditional methods consistent with phylogenetic analysis of 18S rRNA sequences showed SRBP_ZSHSG1 has 100% similarity with Trichoderma strains and the most closest is Trichoderma asperellum. Thus, it proposed name Trichoderma asperellum SRBP_ZSHSG1 (ID: KP336489). Results proved SRBP_ZSHSG1 followed by T. roseum and Chaetomium globosum were highly inhibitors to the tested pathogens. These results were confirmed by field experiments. SRBP_ZSHSG1 was able to grow on rice straw (biostraw) and produce most active compounds. The biostaw extract was the most effective bioagent and recorded highest reduction in pathogen numbers. GC/MS analysis of ethyl acetate extract revealed the presence of 9 compounds. These compounds were determined 4 volatile alcohols (1-4) and fatty acid esters (5-9).