Decolorization of synthetic dyes by laccase produced from newly isolated Trametes hirsuta EDN084 under in-vitro condition was investigated in this study. Partial purification was conducted using ultrafiltration Amicon 10K at 5000 x g for 20 min. Laccase (0.1 U/mL) could decolorize 50% remazol brilliant blue R (RBBR), 47% reactive blue 4 (RBlue4), 51% acid blue 129 (AB129), 21% acid blue 25 (AB25), 40% acid blue 113 (AB113), 11% acid orange 7 (AO7), 2% reactive black 5 (RBlack5), 2% reactive red 120 (RR120), and 85% direct blue 71 (DBlue71) for 4 h. In order to improve the decolorization, the addition of violuric acid (VA), 2, 2, 6, 6-tetramethylpiperidine 1-oxyl (TEMPO), and 1-hydroxybenzotriazole (HBT) were individually assayed. The result showed that decolorization was improved significantly (2 to 30-fold) after the addition of 1 mM VA. This study suggests that mediator VA is suitable for the enhanced decolorization of synthetic dyes by laccase from T. hirsuta EDN084.
Styrofoam wastes are composed of many polymerized styrene monomers that are generally considered to be recalcitrant and are resistant to biodegradation. In this study, the ability of ligninolytic fungi and bacteria were investigated on degradation of styrofoam wastes. All the fungi and bacteria used were able to grow on agar media containing styrofoam. Fungi Cymatoderma dendriticum WM01, Ceriporia sp. BIOM3, and Pestalotiopsis sp. NG007 degraded 15.7%, 19.4%, and 74.4% styrofoam within 30 d, respectively. Cerratia marcescens BLSP4, Bacillus subtilis BLSP4, and Pseudomonas aeruginosa BLSP4 degraded 38.3%, 52.6%, and 63.4% styrofoam, respectively. SEM analysis demonstrated the appearance of micro pore in styrofoams treated with Pestalotiopsis sp. NG007 and P. aeruginosa indicating biodegradation. In addition, analysis using UATR FTIR corroborated removal of some functional groups from the degraded styrofoam were eliminated. This study showed strains of ligninolytic fungi and selected bacteria have the potential to be used in bioremediation of styrofoam wastes.
Water pollution by dyes represents from dyestuff industry becomes an environmental concern. Finding new isolates capable of decolorizing these dyes is important. The study aimed to assess the new isolates of white-rot fungi (WRF) as decolorizing agent of anthraquinone and azo dyes. Decolorization assay were conducted in Agar plates and liquid medium. During the decolorization, laccase activities produced by the fungal strains were analyzed. Identification of the fungal strains were investigated using molecular DNA analysis. The results showed that isolates M3, H18, and GP1 were able to decolorize anthraquinone and azo dyes in Agar and liquid medium. Based on DNA analysis, isolates M3, H18, and GP1 have the similarity to Trametes sanguinea, Trametes polyzona, and Neofomitella guangxiensis, respectively. Among the fungi, T. polyzona H18 exhibited high decolorization ability (70–90%) to the dyes (100 mg/L) after 96-hours incubation. Laccase activity was fluctuated during the reactions with tendency to increase at the beginning until its peak, then decreased at the end of incubation. This study demonstrated the potential of the new isolates from Indonesia to decolorize anthraquinone and azo dyes. The results of the study can provide an alteranative for bioremediation agents of contaminated water by synthetic dyes.
Abstract. Developing an effective pretreatment for the conversion of lignocellulosic biomass to ethanol is an important effort in reducing the cost of this process. Microwave-assisted pretreatment is considered a green technology that can effectively break down lignocellulosic structures. The objective of this study was to investigate the most effective temperature for microwave-assisted oxalic acid pretreatment regarding the structural characteristic changes of oil palm empty fruit bunches (OPEFB) fibers. The fibers were subjected to microwave-assisted oxalic acid pretreatment at 160-200 °C with 2.5 minutes heating time and a liquid to solid ratio of 10. The effectiveness of the pretreatment was determined based on its delignification selectivity, morphological characteristics, and functional group changes. Microwave irradiation of OPEFB fibers at 180 ºC was effective in increasing the cellulose content by 24%. This pretreatment resulted in 1.82 delignification selectivity. More than 50% of the hemicellulose of the OPEFB was removed after this treatment, which was confirmed by a decrease of the absorption bands of functional groups at 1732 cm -1 . The increase of pretreatment temperature disrupted the morphological structure of the OPEFB and removed its hemicellulose but did not change its functional groups and lignin content.
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