19 research outputs found
Remarkable impact of PAHs and TPHs on the richness and diversity of bacterial species in surface soils exposed to long-term hydrocarbon pollution
Nowadays, because of substantial use of
petroleum-derived fuels the number and extension of
hydrocarbon polluted terrestrial ecosystems is in growth
worldwide. In remediation of aforementioned sites bioremediation
still tends to be an innovative, environmentally
attractive technology. Although huge amount of information
is available concerning the hydrocarbon degradation
potential of cultivable hydrocarbonoclastic bacteria little is
known about the in situ long-term effects of petroleum
derived compounds on the structure of soil microbiota.
Therefore, in this study our aim was to determine the longterm
impact of total petroleum hydrocarbons (TPHs),
volatile petroleum hydrocarbons (VPHs), total alkyl benzenes
(TABs) as well as of polycyclic aromatic hydrocarbons
(PAHs) on the structure of bacterial communities of
four different contaminated soil samples. Our results
indicated that a very high amount of TPH affected positively
the diversity of hydrocarbonoclastic bacteria. This
finding was supported by the occurrence of representatives
of the a-, b-, c-Proteobacteria, Actinobacteria, Flavobacteriia
and Bacilli classes. High concentration of
VPHs and TABs contributed to the predominance of actinobacterial
isolates. In PAH impacted samples the concentration
of PAHs negatively correlated with the diversity
of bacterial species. Heavily PAH polluted soil samples
were mainly inhabited by the representatives of the b-, c-
Proteobacteria (overwhelming dominance of Pseudomonas
sp.) and Actinobacteria
Különböző talajtípusokon termesztett búzafű (Triticum aestivum L.) és búzamag szeléntartalma összefüggésének vizsgálata
In Vitro and In Vivo Effect of Poplar Bud Extracts on Phytophthora infestans: A New Effective Biological Method in Potato Late Blight Control
The effect of populin extract from black poplar (Populus nigra) on seven different late blight strains was tested under laboratory and field conditions. The growth rate of hyphae was found to be significantly lower in vitro after 3 and 4 v/v% populin applications. Stain M16 was resistant to populin treatment under lab conditions, however. Both 5% and 10% concentration populin reduced the M16 strain’s severity on potato leaves under field conditions and proved to be even more effective than conventionally used fungicides Infinito 687 Sc and Valis M. Higher infection intensity at the 1% level was observed after 24 h using Valis M, and the same trend toward 10% infection remained after 48 and 72 h as well. Low, almost-no-infection intensity was detected after populin 5% and 10% treatment under an open field condition. Altogether, it can be concluded that populin extract can be a low-cost option for growers and an environmentally friendly approach in late blight control
Cultivating conditions optimization of the anaerobic digestion of corn ethanol distillery residuals using response surface methodology.
AbstractThis study investigated the individual and interactive effects of three factors — temperature, inoculum/substrate ratio (ISR) and inoculum typology — on the anaerobic digestion of corn ethanol distillery wastewater. Biochemical methane potential assays planned with factorial design with two independent quantitative variables on three levels (ISR: 1:1, 2:1 and 3:1; temperature: 30°C, 33.5°C, 37°C) and one independent qualitative variable (inoculum type: suspended, granular, mixed) have been performed. Response Surface Methodology has been used to study the effect of the factors with the aim of maximizing the specific methane yields (YCH4) obtainable with this substrate. The results show that all three investigated factors influence in a significant matter the YCH4, the ISR having the strongest effect on it. The temperature has significant influence on the YCH4 only in combination with high ISR values. The optimal conditions for the maximum YCH4 (551 mL CH4 g−1 VSadded) have been found at 37°C operating temperature, ISR=3:1 and using granular inoculum. These conditions gave rise to a 4-fold increase of YCH4 with respect to the worst combination of factors (YCH4=129 mL g−1 VSadded for the suspended inoculum type, at 30°C and ISR=1:1). The results improve the knowledge on the digestion of this substrate, providing information for successful process up-scaling