کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5751346 1619701 2017 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Characteristics of adapted hydrogenotrophic community during biomethanation
ترجمه فارسی عنوان
ویژگی های جامعه هیدروتروپوفی سازگار در هنگام بیومانیزی
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم محیط زیست شیمی زیست محیطی
چکیده انگلیسی


- Acetate accumulation during biomethanation start-up results in reduced CO2 conversion.
- Acid tolerance and product formation evaluated for different microbial consortia.
- 16S rRNA gene sequencing proved altered composition after hydrogenotrophic enrichment.
- Acetate accumulation linked to presence of ~ 50% acetogenic bacteria during start-up.

The results presented in this study were carried out as concomitant experiments during the start-up and operation of a biomethanation unit to evaluate the effect of process parameters on carbon conversion, product formation (methane and acetate) and community composition. For that, two different samples were withdrawn from a trickle-bed reactor with immobilized enrichment culture of hydrogenotrophic methanogens adapted from sewage sludge. One sample was taken from the recirculation liquid during start-up phase while the other was withdrawn directly from the carrier material in the reactor. Elevated acid levels especially during start-up were shown to affect the overall carbon conversion. This effect was also seen during the acid tolerance testing reported here. Final acid concentrations of 1.6 ± 0.3 g/L resulted in a reduced conversion ratio of only 46%. Without acid addition complete conversion of CO2 in the headspace was achieved. However, maximum methane production of 0.55 ± 0.02 mmol after 4 days of incubation was monitored at moderate initial acetate concentration of 0.4 g/L. In both analyzed inoculation materials Methanobacterium species were by far the most dominant Archaea with 21.8% in the recirculation liquid during start-up and 84.8% in the enrichment culture immobilized on the carrier material. The microbial composition of the two analyzed samples is in accordance with the results obtained for the carbon conversion and product formation. With approximately 50% of Bacteroidetes and Firmicutes present during reactor start-up the acetic acid production significantly contributed to the overall carbon conversion. In contrast, methane was produced almost exclusively in trials representing continuous operation where acetogenic bacteria accounted only up to 17.5%. In summary, the acid accumulation monitored during reactor start-up of a biomethanation unit is most likely to result from the microbial composition present. Nevertheless, complete adaptation to hydrogenotrophic conditions was proven to alter the consortium and yield methane as main product alongside high carbon conversion of up to 70.5 ± 1.8%.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Science of The Total Environment - Volume 595, 1 October 2017, Pages 912-919
نویسندگان
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