Peroxidases in YR-1 strain ofMucor circinelloides a potential bioremediator of petroleum-contaminated soils

Abstract

We have studied the induction and subcellular localisation of peroxidase activity present in cell-free extracts of YR-1 strain of Mucor circinelloides in relation with different growth conditions, particularly different carbon sources; the results obtained indicated that the peroxidase expression could be an inducible mechanism depending on the carbon source used. Peroxidase was induced in the presence of hydrocarbons or methanol meanwhile in glucose no activity was founded. On zymograms of peroxidase activity after polyacrylamide gel-electrophoresis two different activity bands were revealed, one of them (major band) shows different relative mobility depending on the aliphatic hydrocarbon chain length used as carbon source, indicating the possibility that could exist different iso-forms of the peroxidase activity. In an immunological approach using a polyclonal antibody against commercial peroxidase, the result shows that the antibody recognised the same two bands revealed in zymogram indicating that activity bands possesses a similar epitope in their structure. On SDS-PAGE loading supernatants obtained by high-speed centrifugation from cell-free extracts of YR-1 grown in glucose, n-decane or methanol, were detected different prominent protein bands at (in kDa): 64 and 94 (glucose), 27 and 46 (n-decane), and 28 and 47 (n-hexadecane) in comparison with a 55 kD band of horseradish peroxidase used as a control. These protein-bands could be the putative subunits of each iso-form in the native protein. Preliminary studies about the intracellular localisation of the enzyme using isopicnic-sucrose gradients suggest that it is located in the peroxisomal fraction.

Gongronella eborensis sp. nov., from vineyard soil of Alentejo (Portugal)

“…Some strains have been described as beneficial to plant growth [2], others display characteristics that allow their use in food fermentation [3,4] and some are responsible for spoilage of foodstuff [5]. Like other filamentous fungi, Mucorales have an important role in nature as decomposers, including the potential to degrade xenobiotic or recalcitrant compounds, solubilize non-soluble minerals and potential for enzyme production [6][7][8][9], which makes them important candidates for biotechnological applications such as bioremediation processes or production of industrially relevant enzymes. Finally, within Mucorales, several species are described as etiological agents of human opportunistic infections (mucormycosis) showing an alarming increase of report cases in recent years [10].…”

Polyacrylamide Gel Electrophoresis an Important Tool for the Detection and Analysis of Enzymatic Activities by Electrophoretic Zymograms

“…Previously we have investigated the use of zymogram staining of native electrophoretic gels as an initial approach to the identification of carbonyl reductase activities against both aliphatic (Silva et al, 2009;Zazueta et al, 2008) and aromatic hydrocarbons (Durón et al, 2005;Zazueta et al, 2003) in Mucor circinelloides YR1, an indigenous fungus isolated from petroleum contaminated soil.…”