Bioprospection of ligninolytic enzymes from marine origin filamentous fungi.

Fungi are excellent producers of extracellular enzymes. Therefore, the present study aimed to investigate the screening of marine fungi, which are laccase and manganese peroxidase potential producers, in solid fermentation for future applications in bioremediation processes of contaminated sites. For this purpose, two-level factorial planning was adopted, using time (6 and 15 days) and the absence or presence of oil (0 and 1%) as factors. The semi-quantitative evaluation was carried out by calculating radial growth, enzyme activity and enzyme index by measuring phenol red or syringaldazine oxidation halo. The results showed that all the studied strains showed a positive result for manganese peroxidase production, with an enzymatic activity in solid medium less than 0.61, indicating a strongly positive activity. Through the enzyme index, the study also showed prominence for Penicillium sp. strains, with values > 2. The enzyme index increase in oil presence and the inexpressive use of the genera studied for ligninolytic enzymes production from crude oil demonstrated these data importance for fermentative processes optimization. Considering the ability of these strains to develop into recalcitrant compounds and the potential for manganese peroxidase production, they are indicated for exploitation in various bioremediation technologies, as well as other biotechnological applications.

Sequential determination and chemical speciation analysis of inorganic As and Sb in airborne particulate matter collected in outdoor and indoor environments using slurry sampling and detection by HG AAS.

In this work, fast sequential determination and chemical speciation analysis of inorganic arsenic and antimony in airborne particulate matter collected in outdoor and indoor environments using slurry sampling and detection by hydride generation atomic absorption spectrometry (HG-AAS) is proposed. A Doehlert design was applied to optimise the hydride generation conditions of As and Sb for fast sequential determination in the same aliquot of particulate matter samples after preparation of the slurry. The limits of quantification (LoQ) obtained for As and Sb were 0.3 and 0.9 ng m-3, respectively. The accuracy of the analytical method was confirmed by analysis of the certified reference material of urban particulate matter (SRM NIST 1648a), presenting concordance with certified values of 92.7±7.7% for As and 91.2±9.5% for Sb. Precision was expressed as relative standard deviation (% RSD, n=3), with our results presenting values better than 3.4% and 4.2% for total inorganic As and Sb, respectively. For all analysed samples, total As concentrations and its inorganic species were below the LoQ of the analytical method (<0.3 ng m-3). However, the averages of total inorganic Sb concentrations in airborne particulate matter, collected as total suspended outdoor particles (TSPoutdoor), inhalable particulate matter (PM10), and total suspended indoor particles (TSPindoor), were 3.1±0.5, 2.4±0.6, and 2.6±0.4 ng m-3, respectively. Trivalent Sb (Sb3+) was the predominant inorganic species in all samples investigated, with mean percentages of 76%, 72%, and 73% in TSPoutdoor, PM10, and TSPindoor, respectively. The presence of Sb and its predominant inorganic form (Sb3+) can be attributed to vehicular traffic close to the sampled urban areas. Therefore, fast sequential determination of As and Sb and their inorganic species in particulate matter samples prepared as slurry by FS-HG-AAS is an efficient, accurate, and precise method and can be successfully applied to routine analysis.

Optimization of sample preparation procedures for evaluation of the mineral composition of fish feeds using ICP-based methods.

This work describes the application of an experimental design in optimizing the decomposition and spectrometer operational conditions for analysis of fish feeds. The content of 22 elements (six macroelements, four microelements and eleven trace elements) in feeds for fishes (ornamental and for human consumption) was determined by inductively coupled plasma (ICP)-based methods. Limits of quantification were obtained and the values ranged between 0.02 mg kg-1 (Cd) and 76 mg kg-1 (Al). Evaluation of the methods was achieved through analysis of standard reference material, Oyster Tissue (NIST 1566b) and Tea (NCS DC 73351). Element concentrations in feed samples for ornamental fish ranged from <0.02 mg kg-1 (Cd) to 2.79% (P) and for fish breeding for human consumption from <0.02 mg kg-1 (Cd) to 2.00% (Ca). The concentrations of the elements obtained in the analyzed fish feeds were within the limits established by Brazilian and American legislation for regulated elements.