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The development of rapid techniques, such as hyperspectral spectrophotometry, for investigating arsenic (As) soil contamination could be of great value with respect to conventional methods. This study was conducted to detect As concentrations in artificially polluted soils (from 25 to 1045 mg kg−1) through hyperspectral visible–near infrared spectrophotometry and to compare two multivariate statistical regression analyses: partial least squares and support vector machines. The correlation coefficient r is greater in the partial least squares in both model (0.93%) and test (0.87%) with respect to support vector machines (0.88% for the model and 0.82% for the test). The most important model variables extracted from the variable importance in projection scores resulted the absorption peaks at 580, 660, 715, and 780 nm. Bands in the visible spectra are not directly associated to As, but the metalloid can interact with the main spectrally active components of soil permitting to multivariate statistical models ...

The MBEC(TM)-High Throughput Assay based on the Calgary Biofilm Device was used to produce and to characterize Pleurotus ostreatus biofilms. Hydroxyapatite coating of pegs was required to enable biofilm attachment; biofilm amounts and homogeneity of distribution were markedly improved upon removal of non-sessile biomass after 48 h from inoculation. Scanning electron microscopy showed surface-associated and multi-layered growth stabilized by the presence of an extracellular matrix (ECM). Biofilms had higher contents of total sugars and ECM than their free-floating counterparts. Tolerance to Cr(VI) in the former was about twice that of the latter as inferred by the respective inhibitory concentrations (48.4 vs 24.1 mM and 114.5 vs 61.0 mM in 4- and 7-d-old cultures, respectively). Biofilms also displayed superior olive-mill wastewater (OMW) treatment efficiency along 5 consecutive batches leading to chemical oxygen demand and total phenol removals higher than 50 and 90%, respectively. Laccase activity peaks in biofilm cultures grown on OMW were significantly higher than those in free-floating cultures.

The morphological development of a glucoamylase-producing strain of Aureobasidium pullulans immobilized in Ca-alginate was investigated during semicontinuous fermentations in a fluidized-bed reactor. A dense mycelium layer was developed by the fungus on the gel bead surface which gave the beads a "pellet-like" configuration. Varying culture conditions, such as bead, substrate and CaCl2 concentrations and aeration rate, had a consistent effect on both enzyme production and morphological development of the "in situ" grown cells. Optimization of the growth conditions appeared to be necessary to prevent fungal overgrowth and to enable the immobilized inoculum to continue a sustained level of glucoamylase production over a great number of transfers.

Fungi have long been known as enzyme producers and some species are being exploited industrially to make, e.g., amylases and cellulases (Priest, 1984). Among others, some species of the genus Penicillium have been reported to possess enzymes with high levels of activity (AbdelFattah et al., 1972; Ghosh and Thangamani, 1973; Yamasaki et al., 1977). In this short communication we report the results of a preliminary screening conducted on 40 strains, representing 24 species of Penicillium, for the production of enzymes of possible industrial interest. The strains used in this study were obtained from the culture collections of the Dipartimento di Biologia Vegetale, University of Perugia, Italy, and the Istituto Superiore di Sanita, Rome, Italy. Stock cultures were maintained at 5 C on slants