- J. Iglesias (1)
- Ana J. Cavaleiro (1)
- A.A.M. Langenhoff (1)
- M.J. Lombardia (1)
- A.M.S. Paulo (1)
- A.J.M. Stams (1)
Enhancement of methane production from 1-hexadecene by additional electron donors
Paulo, A.M.S. ; Salvador, Andreia F. ; Alves, J.I. ; Castro, R. ; Langenhoff, A.A.M. ; Stams, A.J.M. ; Cavaleiro, Ana J. - \ 2018
Microbial Biotechnology 11 (2018)4. - ISSN 1751-7907 - p. 657 - 666.
1-Hexadecene-contaminated wastewater is produced in oil refineries and can be treated in methanogenic bioreactors, although generally at low conversion rates. In this study, a microbial culture able to degrade 1-hexadecene was enriched, and different stimulation strategies were tested for enhancing 1-hexadecene conversion to methane. Seven and three times faster methane production was obtained in cultures stimulated with yeast extract or lactate, respectively, while cultures amended with crotonate lost the ability to degrade 1-hexadecene. Methane production from 1-hexadecene was not enhanced by the addition of extra hydrogenotrophic methanogens. Bacteria closely related to Syntrophus and Smithella were detected in 1-hexadecene-degrading cultures, but not in the ones amended with crotonate, which suggests the involvement of these bacteria in 1-hexadecene degradation. Genes coding for alkylsuccinate synthase alpha-subunit were detected in cultures degrading 1-hexadecene, indicating that hydrocarbon activation may occur by fumarate addition. These findings are novel and show that methane production from 1-hexadecene is improved by the addition of yeast extract or lactate. These extra electron donors may be considered as a potential bioremediation strategy of oil-contaminated sites with bioenergy generation through methane production.
Susceptibility of the eggs of the field slug Deroceras reticulatum to contact with pesticides and substances of biological origin on artificial soil
Iglesias, J. ; Castillejo, J. ; Ester, A. ; Castro, R. ; Lombardia, M.J. - \ 2002
Annals of Applied Biology 140 (2002)1. - ISSN 0003-4746 - p. 53 - 59.
seed-applied pesticides - muller pulmonata - perennial ryegrass - winter-wheat - limacidae - baits - molluscicides - toxicity - barley - damage
The toxicity of 14 substances, including a number of pesticides, to the eggs of the pest slug Deroceras reticulatum was determined in laboratory experiments. Eggs were kept in contact with a precisely defined artificial soil to which a range of concentrations of the test substances had been applied. Mortality of the eggs was assessed every 24 h and the median lethal doses (LD50) were determined. The herbicides bromoxynil, ioxynil and pyridate + bromoxynil, the insecticides thiocyclam, diflubenzuron and azadirachtin, the molluscicides metaldehyde and methiocarb, and other compounds such as carvone, iron-EDDHA, saponin, and an extract of Pongamia pinnata, killed the eggs after periods of exposure ranging from 2 to 14 days, depending on the compound and the dose. Only two compounds, the insecticides imidacloprid and teflubenzuron, failed to kill the eggs of D. reticulatum at any of the doses tested. Values of LD50 below 0.01 mg a.i. cm-2 were obtained for the herbicides bromoxynil, ioxynil and pyridate + bromoxynil, and for the biological pesticide azadirachtin. The feasibility of slug egg control in different contexts is discussed