Risky Ayu Kristanti

Fate and cometabolic degradation of benzo(a)pyrene by white-rot fungus Armillaria sp. F022

Armillaria sp. F022, a white-rot fungus isolated from a tropical rain forest in Samarinda, Indonesia, was used to biodegrade benzo[a]pyrene (BaP). Transformation of BaP, a 5-ring polycyclic aromatic hydrocarbon (PAH), by Armillaria sp. F022, which uses BaP as a source of carbon and energy, was investigated. However, biodegradation of BaP has been limited because of its bioavailability and toxicity. Five cosubstrates were selected as cometabolic carbon and energy sources. The results showed that Armillaria sp. F022 used BaP with and without cosubstrates. A 2.5-fold increase in degradation efficiency was achieved after addition of glucose. Meanwhile, the use of glucose as a cosubstrate could significantly stimulate laccase production compared with other cosubstrates and not using any cosubstrate. The metabolic pathway was elucidated by identifying metabolites, conducting biotransformation studies, and monitoring enzyme activities in cell-free extracts. The degradation mechanism was determined through the identification of several metabolites: benzo[a]pyrene-1,6-quinone, 1-hydroxy-2-benzoic acid, and benzoic acid.

Identification of metabolites from benzo[a]pyrene oxidation by ligninolytic enzymes of Polyporus sp. S133

The biodegradation of benzo[a]pyrene (BaP) by using Polyporus sp. S133, a white-rot fungus isolated from oil-contaminated soil was investigated. Approximately 73% of the initial concentration of BaP was degraded within 30 d of incubation. The isolation and characterization of 3 metabolites by thin layer chromatography, column chromatography, and UV-vis spectrophotometry in combination with gas chromatography-mass spectrometry, indicated that Polyporus sp. S133 transformed BaP to BaP-1,6-quinone. This quinone was further degraded in 2 ways. First, BaP-1,6-quinone was decarboxylated and oxidized to form coumarin, which was then hydroxylated to hydroxycoumarin, and finally to hydroxyphenyl acetic acid by addition of an epoxide group. Second, Polyporus sp. S133 converted BaP-1,6-quinone into a major product, 1-hydroxy-2-naphthoic acid. During degradation, free extracellular laccase was detected with reduced activity of lignin peroxidase, manganese-dependent peroxidase and 2,3-dioxygenase, suggesting that laccase and 1,2-dioxygenase might play an important role in the transformation of PAHs compounds.

Potential of a white-rot fungus Pleurotus eryngii F032 for degradation and transformation of fluorene

The white-rot fungus Pleurotus eryngii F032 showed the capability to degrade a three fused-ring aromatic hydrocarbons fluorene. The elimination of fluorene through sorption was also investigated. Enzyme production is accompanied by an increase in biomass of P. eryngii F032 during degradation process. The fungus totally degraded fluorine within 23 d at 10-mg l(-1) solution. Fluorene degradation was affected with initial fluorene concentrations. The highest enzyme activity was shown by laccase in the 10-mg l(-1) culture after 30 d of incubation (1620 U l(-1)). Few activities of enzymes were observed in the fungal cell at the varying concentration of fluorene. Three metabolic were detected and separated in ethylacetate extract, after isolated by column chromatography. The metabolites, 9-fluorenone, phthalic acid, and benzoic acid were identified using UV-vis spectrophotometer and gas chromatography-mass spectrometry (GC-MS). The results show the presence of a complex mechanism for the regulation of fluorene-degrading enzymes.

Identification of naphthalene metabolism by white rot fungus Armillaria sp. F022

Armillaria sp. F022, a white rot fungus isolated from tropical rain forest (Samarinda, Indonesia) was used to biodegrade naphthalene in cultured medium. Transformation of naphthalene by Armillaria sp. F022 which is able to use naphthalene, a two ring-polycyclic aromatic hydrocarbon (PAH) as a source of carbon and energy was investigated. The metabolic pathway was elucidated by identifying metabolites, biotransformation studies and monitoring enzyme activities in cell-free extracts. The identification of metabolites suggests that Armillaria sp. F022 initiates its attack on naphthalene by dioxygenation at its C-1 and C-4 positions to give 1,4-naphthoquinone. The intermediate 2-hydroxybenzaldehyde and salicylic acid, and the characteristic of the meta-cleavage of the resulting diol were identified in the long-term incubation. A part from typical metabolites of naphthalene degradation known from mesophiles, benzoic acid was identified as the next intermediate for the naphthalene pathway of this Armillaria sp. F022. Neither phthalic acid, catechol and cis,cis-muconic acid metabolites were detected in culture extracts. Several enzymes (manganese peroxidase, lignin peroxidase, laccase, 1,2-dioxygenase and 2,3-dioxygenase) produced by Armillaria sp. F022 were detected during the incubation.

EFFECT OF ENVIRONMENTAL FACTORS IN THE DECOLORIZATION OF REMAZOL BRILLIANT BLUE R BY POLYPORUS SP. S133

The effects of environmental conditions such as pH, agitation, carbon and nitrogen sources, metal ion, salinity and phenolic compound on the decolorization of the anthraquinone type textile dyestuff Remazol Brilliant Blue R by white rot fungi, Polyporus sp. S133 were investigated. After extensive testing, the best performance took place at pH 4 and decolorization of the dye in liquid effluents was significantly increased by agitation. Compared to other carbon and nitrogen sources tested, glucose and ammonium tartrate gave rise to better decolorization performances. Decolorization of RBBR occurred in the presence of metal ions which are typically found in textile industry effluents. Of all the metal ions tested, Fe ++ was the most inhibiting of the decolorization. The effect of culture salinity on decolorization was also investigated. Under high-salt conditions, RBBR was also decolorized completely in 6 d. The presence of phenolic compounds inhibited the decolorization at a concentration of 1 mM, but protocatechuic acid showed no inhibition. The results indicate that possibly anthraquinone type dyes such as RBBR act as enzyme substrates that are directly oxidized by laccase.

Accelerated biodegradation of nitrophenols in the rhizosphere of Spirodela polyrrhiza.

We investigated the biodegradation of 2-nitrophenol (2-NP), 4-nitrophenol (4-NP), and 2,4-dinitrophenol (2,4-DNP) in the rhizosphere of Spirodela polyrrhiza plants by conducting degradation experiments with three river water samples supplemented with each nitrophenol (NP). We then isolated NP-degrading bacteria both from the S. polyrrhiza roots and from the river water. In the river water samples, removal of the three NP was accelerated in the presence of S. polyrrhiza plants. The three NPs persisted in an autoclaved solution with sterile plants suggests that NP removal was accelerated largely by bacterial NP biodegradation rather than by adsorption and uptake by the plants. We isolated 8 strains of NP-degrading bacteria: 6 strains from the S. polyrrhiza roots and 2 strains from river water without the plants. The 2-NP- and 2,4-DNP-degrading bacteria were isolated only from the S. polyrrhiza roots. The 4-NP-degrading bacteria different from those isolated from the river water samples were also found on S. polyrrhiza roots. The 2-NP- and 4-NP-degrading strains isolated from the roots utilized the corresponding NP (0.5 mmol/L) as the sole carbon and energy source. The 2,4-DNP-degrading strains isolated from the roots showed substantial 2,4-DNP-degrading activity, but the presence of other carbon and energy sources was required for their growth. The isolated NP-degrading bacteria from the roots must have contributed to the accelerated degradation of the three NPs in the rhizosphere of S. polyrrhiza. Our results suggested that rhizoremediation with S. polyrrhiza may be effective for NP-contaminated surface water.

Characterization of pyrene biodegradation by white‐rot fungus Polyporus sp. S133

A white‐rot fungus of Polyporus sp. S133 was isolated from an oil‐polluted soil. The metabolism of pyrene by this fungus was investigated in liquid medium with 5 mg of the compound. Depletion of pyrene was evident during the 30‐day growth period and was 21% and 90%, respectively, in cometabolism and metabolism of pyrene alone. Pyrene was absorbed to fungal cells or biodegraded to form simpler structural compounds. Seventy‐one percent of eliminated pyrene was transformed by Polyporus sp. S133 into other compounds, whereas only 18% was absorbed in the fungal cell. The effects of pH and temperature on biomass production of Polyporus sp. S133 for pyrene were examined; the properties of laccase and 1,2‐dioxygenase produced by Polyporus sp. S133 during pyrene degradation were investigated. The optimal values of pH were 3, 5, and 4 for laccase, 1,2‐dioxygenase, and biomass production, respectively, whereas the optimal values of temperature were 25 °C for laccase and 50 °C for 1,2‐dioxygenase and biomass production. Under optimal conditions, pyrene was mainly metabolized to 1‐hydroxypyrene and gentisic acid. The structure of 1‐hydroxypyrene and gentisic acid was determined by gas chromatography–mass spectrometry after identification using thin‐layer chromatography.

Treatability of methylene blue solution by adsorption process using neobalanocarpus hepmii and capsicum annuum

The effectiveness of adsorbent agent from agricultural wastes and biomass to remove dye from aqueous solution was investigated. In this study, solution of methylene blue (MB) and two adsorbents, bark of cengal tree (Neobalanocarpus hepmii) and seed of red chili (Capsicum annuum), were tested. Experiments were performed with testing MB solution at 3-h interval and also testing with different quantities of adsorbent. In addition, the further study on characterization of adsorbent by Field Emission Scanning Electron Microscopy (FESEM) and Fourier Transform Infrared Spectroscopy (FTIR) was conducted in order to elucidate the properties and surface structure of the adsorbents. Analysis from UV-Vis spectroscopy showed that both adsorbents remove MB dye effectively and according to FESEM analysis due to the structure of the adsorbent were perforated and consist of polymer components. On the other hand, in FTIR perspective, the adsorption was successful because of the presence of carboxyl and carbonyl groups from both adsorbent that helps enhanced the process of adsorption.

Bioaugmentation involving a bacterial consortium isolated from the rhizosphere of Spirodela polyrhiza for treating water contaminated with a mixture of four nitrophenol isomers

A flask-scale laboratory study was performed to assess the bioaugmentation of water contaminated with a mixture of 2-nitrophenol, 3-nitrophenol, 4-nitrophenol and 2,4-dinitrophenol by using a bacteria consortium consisting of three nitrophenol-degrading bacteria strains (Pseudomonas sp. strain MFR-1, Pseudomonas sp. strain PFR-1 and Rhodococcus sp. strain DFR-1), reinoculated into the roots of Spirodela polyrhiza. The selected strains were colonized into the root at approximately 104 to 106 colony-forming units (CFU per plant). The high populations remained stable through five sequential two-days degradation cycles and complete nitrophenol removal was achieved within five-repeated cycles. Hence, inoculation of subjected degraders into the roots of aquatic plants is an effective treatment for nitrophenol-contaminated effluents or aquatic resources.

Biotransformation studies of cresol red by Absidia spinosa M15

Cresol Red, a commercial dye that used widely to color nylon, wool, cotton, and polyacrylonitrile-modified nylon in the massive textile manufacture is toxic recalcitrant. Absidia spinosa M15, a novel fungal strain isolated from a tropical rain forest, was found to decolorize Cresol Red 65% within 30 d under agitation condition. UV-Vis spectroscopy, TLC analysis and mass spectra of samples after decolorization process in culture medium confirmed final decolorization of Cresol Red. Two metabolites were identified in the treated medium: benzeneacetic acid (tR 9.6 min and m/z 136) and benzoic acid (tR 5.7 min and m/z 122). Laccase showed the significant activity (133.8 U/L) in biomass obtained at the end of experiment demonstrates role of the enzyme in the decolorization process.