Dede Heri Yuli Yanto

The potential of fungal co-culture of the filamentous Pestalotiopsis sp. NG007 with four different basidiomycetes — Trametes versicolor U97, Pleurotus ostreatus PL1, Cerena sp. F0607, and Polyporus sp. S133 — for accelerating biodegradation of petroleum hydrocarbons (PHCs) was studied using three different physicochemical characteristic PHCs in soil. All the combinations showed a mutual intermingling mycelial interaction on the agar plates. However, only NG007/S133 (50/50) exhibited an optimum growth rate and enzymatic activities that supported the degradation of asphalt in soil. The co-culture also degraded all fractions at even higher concentrations of the different PHCs. In addition, asphaltene, which is a difficult fraction for a single microorganism to degrade, was markedly degraded by the co-culture, which indicated that the simultaneous biodegradation of aliphatic, aromatic, resin, and asphaltene fractions had occurred in the co-culture. An examination of in-vitro degradation by the crude enzymes and the retrieval fungal culture from the soil after the experiment confirmed the accelerated biodegradation due to enhanced enzyme activities in the co-culture. The addition of piperonyl butoxide or AgNO3 inhibited biodegradation by 81–99%, which demonstrated the important role of P450 monooxygenases and/or dioxygenases in the initial degradation of the aliphatic and aromatic fractions in PHCs.

Asphalt and fractions thereof can contaminate water and soil environments. Forming as residues in distillation products in crude oil refineries, asphalts consist mostly of asphaltene instead of aliphatics, aromatics, and resins. The high asphaltene content might be responsible for the decrease in bioavailability to microorganisms and therefore reduce the biodegradability of asphalt in the environment. In this study, the effect on asphalt biodegradation by Pestalotiopsis sp. in liquid medium and soil of nonionic Tween surfactants in the presence of Mn2+ and H2O2 was examined. The degradation was enhanced by Tween 40 or Tween 80 (0.1%) in the presence of Mn2+ (1 mM) and H2O2 (0.05 mM). A Tween surfactant, Mn2+, and H2O2 can overcome bioavailability-mediated constraints and increase ligninolytic activities, particularly manganese peroxidase and laccase activities. The study is significant for the bioremediation of asphalt and/or viscous-crude oil-contaminated environments.

Evidence for the biodegradation and biotransformation of petroleum hydrocarbons by Pestalotiopsis sp. has recently emerged. Out of seventy-two strains tested, Pestalotiopsis sp. NG007, identified from its gene sequence and morphological characteristics grew most actively on asphalt-containing agar media. The strain exhibited the ability to degrade all types of petroleum hydrocarbons (48–96% over 30 days) in liquid medium at pH 4.5 and saline conditions at pH 8.2. During the biodegradation of an aliphatic mixture (n-decane, n-undecane, n-dodecane, n-tetradecane, n-pentadecane, n-hexadecane, n-octadecane, n-nonadecane, n-eicosane and pristane), fifteen metabolites were detected. The presence of fatty alcohols, fatty aldehydes, and fatty acids (mono- and di- carboxylic acid) as intermediate products showed that NG007 can degrade and transform aliphatic fractions not only via mono- or di-terminal oxidation, but also via sub-terminal and alkyl peroxide oxidation. In the presence of petroleum hydrocarbons, both dioxygenases and ligninolytic activities were detected. The wide-ranging activity observed and the case of growth using petroleum hydrocarbons as the sole carbon source suggest that Pestalotiopsis sp. NG007 is a potential source for bioremediation of petroleum-contaminated environments.


Keywords: Biodegradation; Dioxygenases; Ligninolytic enzymes; Monooxygenase; Pestalotiopsis sp.; Petroleum hydrocarbons

Wastewater from textile industry effluents contains high amounts of colored and toxic compounds that can interrupt aquatic life systems when they are discharged to the environment without being treated. The physicochemical characteristics of effluents typically have a wide range of pHs and salinities, which are difficult for conventional techniques to remove. In addition, a limited number of microorganisms with the ability to grow and produce degradative enzyme systems can survive under those condition. Therefore, identifying microorganisms that are capable of decolorizing and degrading textile dyes under various pHs and salinities is needed. Among the fifteen strains tested in this study, Pestalotiopsis sp. NG007 exhibited the strongest ability to grow and decolorize Reactive Red 4 under saline conditions at pH 8. The ability of this strain to decolorize three textile dyes: Reactive Green 19, Reactive Orange 64 and Reactive Red 4, was investigated in a liquid medium and bioreactor system using immobilized mycelia. The fungus displayed a high decolorization capacity (20-98%) over 3 days in a wide range of pHs (pH 3-12) and salinities (0-10% w/v). In the bioreactor system, immobilized mycelia of the strain exhibited the ability to decolorize textile dyes by both adsorption (6-53%) and degradation (34-41%) mechanisms. This study demonstrated that Pestalotiopsis sp. has the potential to decolorize textile dye effluents containing a wide range of pHs and salinities.

The invention relates to a composite material which comprises admixture of kenaf (Hibiscus cannabinus) bast micro fibers and a polymer of polypropylene and/or polylactic acid, wherein the micro fibers are contained in an amount of 20 to 80 % by weight. According to the present invention, composite material for automotive components that has high strength and environmentally friendly composed of kenaf micro fiber and polypropylene or polylactic acid matrices can be achieved.