Biomonitoring of airborne trace elements using transplanted lichens around a paper industry (Morelia, Mexico).

The deposition of trace elements around a pulp and paper industry in Morelia, Mexico, was evaluated using two lichen species as biomonitors. Samples of the foliose lichen Flavopunctelia praesignis and the fruticose lichen Usnea ceratina were collected in two remote areas and transplanted at different distances and directions from the pollution source. Lichen samples were exposed for 4 months (1) around the industrial area and (2) in their native habitats (control sites). We investigated the bioaccumulation of 11 trace elements in lichen thalli, and we compared the response of the two lichen species. To identify possible common sources, we evaluated the relationships between trace elements by correlations and cluster analyses. Our results showed that Cd was a good tracer for air pollution from the pulp and paper mills. In samples of Usnea ceratina exposed around the industrial area, Cd was significantly higher than in the remote area. Within the study area, trace element contents increase with the distance from the source, and they showed high depositions in the direction of prevailing winds. Moreover, we were able to detect groups of elements with similar behavior and common origins. Our results indicated that Flavopunctelia praesignis showed a higher capacity to accumulate trace elements than Usnea ceratina.

Typing and selection of wild strains of Trichoderma spp. producers of extracellular laccase.

Using the ITS region and the gene tef1, 23 strains of the genus Trichoderma were identified as belonging to the species T. harzianum (n = 14), T. olivascens (n = 1), T. trixiae (n = 1), T. viridialbum (n = 1), T. tomentosum (n = 2), T. koningii (n = 1), T. atroviride (n = 1), T. viride (n = 1), and T. gamsii (n = 1). Strains expressing extracellular laccase activity were selected by decolorization/oxidation assays in solid media, using azo, anthraquinone, indigoid, and triphenylmethane dyes, and the phenolic substances tannic acid and guaiacol. No strain decolorized Direct Blue 71 or Chicago Blue 6B, but all of them weakly oxidized guaiacol, decolorized Methyl Orange, and efficiently oxidized tannic acid. Based in decolorization/oxidation assays, strains CMU-1 (T. harzianum), CMU-8 (T. atroviride), CMU-218 (T. viride), and CMU-221 (T. tomentosum) were selected for evaluating their extracellular laccase activity in liquid media. Strain CMU-8 showed no basal laccase activity, while strains CMU-1, CMU-218, and CMU-221 had a basal laccase activity of 1,313.88 mU/mL, 763.88 mU/mL, and 799.53 mU/mL, respectively. Addition of sorghum straw inhibited laccase activity in strain CMU-1 by 34%, relative to the basal culture, while strains CMU-8, CMU-21, and CMU-221 increased their laccase activity by 1,321.5%, 64%, and 47%, respectively. These results show that assayed phenolic substrates are good tools for selecting laccase producer strains in Trichoderma. These same assays indicate the potential use of studied strains for bioremediation processes. Straw laccase induction suggests that analyzed strains have potential for straw delignification in biopulping and other biotechnological applications. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:787-798, 2016.