The filamentous fungus produced extracellular antifungal chitinase when cultured under submerged fermentation (SbmF) using crab shells as the carbon source. Maximal chitinase production was achieved at 192 h of cultivation using minimal medium containing 1% chitin. The enzyme was purified 1.97-fold with 40% recovery by ammonium sulfate precipitation and Sephadex G-100 gel filtration. The molecular mass was estimated to be 44 kDa by both 12% SDS-PAGE and Sepharose CL-6B gel filtration. Maximal chitinase activity was obtained at 65 °C and pH 5.0. The enzyme was fully stable at 60 °C for up to 120 min and the enzymatic activity was increased by Mn. In the presence of reducing and denaturing compounds, the enzyme activity was not drastically affected. The chitinase was able to hydrolyze colloidal chitin, azure chitin, and 4-nitrophenyl -acetyl-β-D glucosaminide; for the latter, the and maximal velocity () were 3.51 mM and 9.68 U/mg of protein, respectively. The chitinase presented antifungal activity against (MIC = 84 µg/mL), (MIC = 21 µg/mL), (MIC = 24 µg/mL), (MIC = 24 µg/mL), and (MIC = 21 µg/mL). The fungus was able to produce a thermostable and denaturation-resistant chitinase able to inhibit fungal development, signaling its biotechnological potential.

Tannin acyl hydrolase (EC 3.1.1.20), called tannase, is an enzyme of great biotechnological interest for applications in food, chemical, beverage and pharmaceutical industries. Therefore, the objective of this study was to isolate, select and identify strains of endophytic fungi from rich tannin plants collected in the Caatinga, as well as, the optimization of culture conditions for the best producers. Sixteen endophyte fungi were isolated from the barks of mastic (Myracrodruon urundeuva Allemão), angico (Anadenanthera colubrina Vell.), barauna (Schinopsis brasiliensis Engl.), cajueiro (Anacardium occidentale L.) and catingueira (Caesalpinia pyramidalis Tul). All strains showed ability of using tannic acid as carbon source. The species A. niger and A. fumigatus isolated from angico and cajueiro, respectively, presented the highest enzyme production. The optimum conditions for the production of tannase by A. niger were 24 h cultivation in Khanna medium containing 2% tannic acid, in the absence of nitrogen source, at 37 °C. A. fumigatus showed increased production of tannase when cultured in mineral medium for 24 h using 2% tannic acid as carbon source and peptone as additional nitrogen source, at 37 ºC. The optimum apparent temperature and pH of activity for the enzymes produced by both fungal species were 30 ºC and 4.0, respectively.

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Current researches have been carried out to find microorganisms that can produce enzymes for different biotechnological purposes. Among the enzymes, the microbial phosphatases, responsible for hydrolyzing phosphoric acid anhydrides and esters, have been often employed in different sectors such as molecular biology experiments and clinical diagnosis. This work aims to purify and characterize the alkaline phosphatase produced by Rhizopus microsporus var. microsporus under submerged fermentation. This enzyme was purified 9.9-fold with 13% recovery. The molecular mass for the glycoprotein was 123 kDa estimated with gel filtration and 128 kDa with sodium dodecyl sulfate polyacrylamide gel electrophoresis, indicating that it is a monomeric enzyme. Optimal temperature and pH for the alkaline phosphatase was 45°C and 8.5, respectively, with halflife (t 50 ) of 40 minutes at 50°C. Under alkaline pH, the phosphatase activity was above 50% for 24 hours. FeCl 3 increased the phosphatase activity. Alkaline phosphatase hydrolyzed different substrates, especially p-nitrophenylphosphate, with K m of 0.45 and 0.38 mmol l −1 , in presence and absence of FeCl 3 , respectively. Thus, alkaline phosphatase from R. microsporus var. microsporus was characterized, highlighting important characteristics and, thereby, making possible a future application.