Przemysław Bernat

Degradation of tributyltin by the filamentous fungus Cunninghamella elegans, with involvement of cytochrome P-450

Cunninghamella elegans degraded tributyltin (TBT) at 20 mg l−1 when grown in Sabouraud medium. Above this concentration, growth was inhibited. After 7 d 70% TBT (added at 10 mg l−1) was converted to less toxic derivatives: dibutyltin and monobutyltin. TBT metabolism was totally blocked by cytochrome P-450 inhibitors, metyrapone and proadifen. Only in medium with 1-aminobenzotriazole, was dibutyltin (0.42 mg l−1) found after 7 d of culturing. It is postulated that the significant resistance of C. elegans to TBT is associated with the capacity of the fungus to metabolise TBT.

Tributyltin (TBT) induces oxidative stress and modifies lipid profile in the filamentous fungus Cunninghamella elegans

To investigate the response of the tributyltin-degrading fungal strain Cunninghamella elegans to the organotin, a comparative lipidomics strategy was employed using an LC/MS-MS technique. A total of 49 lipid species were identified. Individual phospholipids were then quantified using a multiple reaction monitoring method. Tributyltin (TBT) caused a decline in the amounts of many molecular species of phosphatidylethanolamine or phosphatidylserine and an increase in the levels of phosphatidic acid, phosphatidylinositol and phosphatidylcholine. In the presence of TBT, it was observed that overall unsaturation was lower than in the control. Lipidome data were analyzed using principal component analysis, which confirmed the compositional changes in membrane lipids in response to TBT. Additionally, treatment of fungal biomass with butyltin led to a significant increase in lipid peroxidation. It is suggested that modification of the phospholipids profile and lipids peroxidation may reflect damage to mycelium caused by TBT.

Butyltins degradation by Cunninghamella elegans and Cochliobolus lunatus co-culture.

Organotin compounds are ubiquitous in environment. However, biodegradation of tributyltin (TBT) and dibutyltin (DBT) to non toxic metabolites by fungi has been seldom observed. In this study we constructed a fungal co-culture with an efficient ability of TBT and its metabolites removal. The microscopic fungus strain Cunninghamella elegans degraded TBT via hydroxybutyldibutyltin (OHBuDBT) to its metabolites: DBT and monobutyltin (MBT), which were then transformed by Cochliobolus lunatus. The sequential biodegradation resulted in a 10-fold decrease in samples toxicity to Artemia franciscana larvae. With an initial TBT concentration of 5 mg l(-1), the co-culture of both fungi almost completely eliminated butyltins during 12 days of incubation in synthetic medium. To our knowledge, this is the first report that the mixed fungal co-culture could efficiently degrade TBT. This process was associated with glucose utilization, and a cometabolic nature of butyltins removal by selected strains has been suggested.

Application of microscopic fungi isolated from polluted industrial areas for polycyclic aromatic hydrocarbons and pentachlorophenol reduction.

The growth abilities of fifteen fungal strains isolated fromcontaminated areas, in the presence of xenobiotics compounds mixture (overworked cuttingfluid, crude and waste oil) were examined. Strains with the richest growth were chosen for anthracene, phenanthrene and pentachlorophenol biodegradation in Sabouraudmedium (with initial xenobiotic concentration 250 mg/l in cultures with polycyclicaromatic hydrocarbons and 10 mg/l for the chlorinated substrate). Strains IM 1063and IM 6325 were able to attack phenanthrene forming its derivative 9-phenanthrenolwith the yields 5.22 mg/l and 2.82 mg/l, respectively. Strain IM 1063 and IM 6325 transformed pentachlorophenol to an intermediatecompound – pentachloromethoxybenzene. Final content of pentachloromethoxybenzene reached 3.46 mg/l and3.2 mg/l, respectively. Strain IM 6203 (contrary to other strains) released an intermediateproduct of pentachlorophenol metabolism – 2,3,5,6-tetrachlorohydroquinone(8.73 mg/l substrate remaining and 1.2 mg/l 2,3,5,6-tetrachlorohydroquinone forming).The IM 6203 strain was identified as Mucor ramosissimus. The chlorinatedpesticide degradation by M. ramossimus was improved significantly on a medium with overworked oil. Only 8.3% of pentachlorophenol and 4.3% of 2,3,5,6-tetrachlorohydroquinone in relation to the introduced substrate (10 mg/l) were found, after7 days of incubation. The growth of M. ramosissimus on medium with overworked oil in pentachlorophenol presence was associated with oil emulgation,which enhanced fungal growth and the pesticide degradation.

Isolation of Streptomyces sp. strain capable of butyltin compounds degradation with high efficiency.

Dibutyltin (DBT), a widely used plastic stabilizer, has been detected in the environment as well as in human tissues. DBT is considered to be highly neurotoxic and immunotoxic. Hence, DBT needs to be considered as a potential toxic chemical. Degradation of butyltin compounds by Streptomyces sp. isolated from plant waste composting heaps was studied. Glucose grown cells degraded organotin from 10 to 40 mg l(-1). After 1 day of incubation 90% of DBT (added at 20 mg l(-1)) was converted to less toxic derivative--monobutyltin (MBT). DBT metabolism was inhibited by metyrapone addition, a known cytochrome P-450 inhibitor. It could provide evidence that cytochrome P-450 system is involved in DBT metabolism in Streptomyces sp. IM P102. Moreover, according to our knowledge, the degradation of DBT by actinobacterium has not been previously described.

Detection of biosurfactants in Bacillus species: genes and products identification.

To screen environmental Bacillus strains for detection of genes encoding the enzymes involved in biosurfactant synthesis and to evaluate their products e.g. surfactin, iturin and fengycin.

Efficient alachlor degradation by the filamentous fungus Paecilomyces marquandii with simultaneous oxidative stress reduction.

The acceleration of alachlor degradation by Paecilomyces marquandii under controlled and optimized conditions of fungal cultivation in liquid batches was observed (by ca. 20% in comparison to the flask cultures). Acidic environment and oxygen limitation resulted in deterioration of herbicide elimination. Efficient xenobiotic degradation did not correlate with free radicals formation, but some conditions of bioreactor cultivation such as neutral pH and oxygen enriched atmosphere (pO2⩾30%) caused a decrease in the reactive oxygen species (ROS) accumulation in mycelia. The changes in the glutathione (GSH) and ascorbic acid (AA) levels, also in the dismutase (SOD) and catalase (CAT) activities showed active response of the tested fungus against alachlor induced oxidative stress. These results will contribute to the improvement of chloroacetanilides elimination by fungi and extend the knowledge concerning oxidative stress induction and fungal cellular defense.

Lipid composition in a strain of Bacillus subtilis, a producer of iturin A lipopeptides that are active against uropathogenic bacteria

Urinary tract infections are a common disease in humans. Therefore, new methods are needed to destroy biofilms that are formed by uropathogens. Iturin A lipopeptides (LPs) C14 and C15 are potent biosurfactants synthetized by the Bacillus subtilis I′1a strain. The biological activity of extracted LPs was confirmed by examining extracts from I′1a cultures against uropathogenic bacteria that had been isolated from biofilms on urinary catheters. Compared with cultures of DSM 3257, which produce surfactin at a relatively low level, the extract obtained from strain I′1a exhibited a greater inhibitory effect against both planktonic and sessile forms of Escherichia coli, Serratia marcescens, Enterobacter cloacae, Proteus mirabilis, Citrobacter freundii and Enterococcus faecalis. Moreover, cyclic LP biosurfactants may disturb the integrity of cytoplasmic membranes; therefore, we investigated the effects of synthetized LPs on fatty acids and phospholipids of B. subtilis. LPs and lipids were analyzed using GC–MS, LC–MS/MS and MALDI-TOF/TOF techniques. Compared with B. subtilis DSM 3257, membranes of the I′1a strain were characterized by an increased amount of anteiso fatty acids and a ten-fold higher ratio of phosphatidylglycerol (PG)-to-phosphatidylethanolamine (PE). Interestingly, in cultures of B. subtilis DSM 3257 supplemented with LP extracts of the I′1a strain, the PG-to-PE ratio was fourfold higher, and the amount of anteiso fatty acids was also increased.Graphical Abstract

Malachite green removal from aqueous solution using the system rapeseed press cake and fungus Myrothecium roridum

AbstractThe waste of rapeseed press cake (WRPC), obtained after the preparation of microbial culture medium, was investigated in a batch system as an adsorbent of malachite green (MG). The effects of the contact time, the temperature, the initial dye concentration and the adsorbent dosage were examined using MG aqueous solutions of pH 6.5. The highest sorption of MG was observed after 180 min in solution containing 50 mg/L of MG and 2.5 mg/L of WRPC. Equilibrium isotherm data was described by the Langmuir, Freundlich and Dubinin-Radushkevich models. The Langmuir expression was found to provide the best correlation. Kinetic models and thermodynamic parameters (Gibbs free energy, enthalpy, and entropy) were also investigated. Experimental data revealed that MG sorption followed the pseudo-second-order rate kinetics. MG desorption efficiency (94.5%) from WRPC with the use of 0.1 M NaOH solution was determined. Biological degradation of the dye-loaded sorbent in a submerged culture of the filamentous fungus M...

Quinoline biodegradation by filamentous fungus Cunninghamella elegans and adaptive modifications of the fungal membrane composition.

Quinoline, which belongs to N-heterocyclic compounds, occurs naturally in the environment and is used in numerous industrial processes. The structures of various chemicals, such as dyes and medicines, are based on this compound. Due to that fact, quinoline and its derivatives are widely distributed in environment and can exert toxic effects on organisms from different trophic levels. The ability of the filamentous fungus Cunninghamella elegans IM 1785/21Gp to degrade quinoline and modulate the membrane composition in response to the pollutant was studied. C. elegans IM 1785/21Gp removes quinoline with high efficiency and transforms the pollutant into two novel hydroxylated derivatives, 2-hydroxyquinoline and 3-hydroxyquinoline. Moreover, due to the disruption in the membrane stability by quinoline, C. elegans IM 1785/21Gp modulates the fatty acid composition and phospholipid profile.