Degradation of endocrine disrupting chemicals by genetic transformants with two lignin degrading enzymes in Phlebia tremellosa

Laccase production and pellet morphology of Coprinopsis cinerea transformants in liquid shake flask cultures

Laccase production and pellet formation of transformants of Coprinopsis cinerea strain FA2222 of C. cinerea laccase gene lcc1 subcloned behind the gpdII-promoter from Agaricus bisporus were compared with a control transformant carrying no extra laccase gene. At the optimum growth temperature of 37 °C, maximal laccase yields of 2.9 U/ml were obtained by the best lcc1 transformant pYSK7-26 in liquid shake flask cultures. Reduction in temperature to 25 °C increased laccase yields up to 9.2 U/ml. The control transformant had no laccase activities at 37 °C but native activity at 25 °C (3.5 U/ml). Changing the temperature had severe effects on the morphology of the mycelial pellets formed during cultivation, but links of distinct pellet morphologies to native or recombinant laccase production could not be established. Automated image analysis was used to characterise pellet formation and morphological parameters (pellet area, diameter, convexity and mycelial structure). Cross sections of selected pellets showed that they differentiated in an outer rind and an inner medulla of loosened hyphae. Pellets at 25 °C had a small and dense outer zone and adopted with time a smooth surface. Pellets at 37 °C had a broader outer zone and a fringy surface due to generation of more and larger protuberances in the rind that when released can serve for production of further pellets.

Fate of Bisphenol A in Terrestrial and Aquatic Environments

Bisphenol A (2,2-bis[4-hydroxyphenyl]propane, BPA), the monomer used to produce polycarbonate plastic and epoxy resins, is weakly estrogenic and therefore of environmental and human health interest. Due to the high production volumes and disposal of products made from BPA, polycarbonate plastic and epoxy resins, BPA has entered terrestrial and aquatic environments. In the presence of oxygen, diverse taxa of bacteria, fungi, algae and even higher plants metabolize BPA, but anaerobic microbial degradation has not been documented. Recent reports demonstrated that abiotic processes mediate BPA transformation and mineralization in the absence of oxygen, indicating that BPA is susceptible to degradation under anoxic conditions. This review summarizes biological and nonbiological processes that lead to BPA transformation and degradation, and identifies research needs to advance predictive understanding of the longevity of BPA and its transformation products in environmental systems.

Molecular characterization of manganese peroxidases from white-rot fungus Polyporus brumalis

The cDNAs of six manganese-dependent peroxidases (MnPs) were isolated from white-rot fungus Polyporus brumalis. The MnP proteins shared similar properties with each other in terms of size (approximately 360-365 amino acids) and primary structure, showing 62-96 % amino acid sequence identity. RT-PCR analysis indicated that these six genes were predominantly expressed in shallow stationary culture (SSC) in a liquid medium. Gene expression was induced by treatment with dibutyl phthalate (DBP) and wood chips. Expression of pbmnp4 was strongly induced by both treatments, whereas that of pbmnp5 was induced only by DBP, while pbmnp6 was induced by wood chips only. Then, we overexpressed pbmnp4 in P. brumalis under the control of the GPD promoter. Overexpression of pbmnp4 effectively increased MnP activity; the transformant that had the highest MnP activity also demonstrated the most effective decolorization of Remazol Brilliant Blue R dye. Identification of MnP cDNAs can contribute to the efficient production of lignin-degradation enzymes and may lead to utilization of basidiomycetous fungi for degradation of lignin and numerous recalcitrant xenobiotics.