Characterisation and microbial community analysis of lipid utilising microorganisms for biogas formation.

Autor: Nzila A; Department of Life Sciences, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia., Razzak SA; Departments of Chemical Engineering, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia., Sankara S; Department of Life Sciences, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia., Nazal MK; Research Institute, Center for Environment and Water, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia., Al-Momani M; Departments of Mathematics & Statistics, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia., Kang GU; School of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, Republic of Korea., Ibal JC; School of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, Republic of Korea., Shin JH; School of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, Republic of Korea.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2019 Nov 08; Vol. 14 (11), pp. e0224989. Date of Electronic Publication: 2019 Nov 08 (Print Publication: 2019).
DOI: 10.1371/journal.pone.0224989
Abstrakt: In the anaerobic process, fat-oil-grease (FOG) is hydrolysed to long-chain fatty acids (LCFAs) and glycerol (GLYC), which are then used as substrates to produce biogas. The increase in FOG and LCFAs inhibits methanogenesis, and so far, most work investigating this inhibition has been carried out when FOG or LCFAs were used as co-substrates. In the current work, the inhibition of methanogenesis by FOG, LCFAs and GLYC was investigated when used as sole substrates. To gain more insight on the dynamics of this process, the change of microbial community was analysed using 16S rRNA gene amplicon sequencing. The results indicate that, as the concentrations of cooking olive oil (CO, which represents FOG) and LCFAs increase, methanogenesis is inhibited. For instance, at 0.01 g. L-1 of FOG, the rate of biogas formation was around 8 ml.L-1.day-1, and this decreased to <4 ml.L-1.day-1 at 40 g.L-1. Similar results were observed with the use of LCFAs. However, GLYC concentrations up to 100g.L-1 did not affect the rate of biogas formation. Acidic pH, temperature > = 45°C and NaCl > 3% led to a significant decrease in the rate of biogas formation. Microbial community analyses were carried out from samples from 3 different bioreactors (CO, OLEI and GLYC), on day 1, 5 and 15. In each bioreactor, microbial communities were dominated by Proteobacteria, Firmicutes and Bacteroidetes phyla. The most important families were Enterobacteriaceae, Pseudomonadaceae and Shewanellaceae (Proteobacteria phylum), Clostridiacea and Ruminococcaceae (Firmicutes) and Porphyromonadaceae and Bacteroidaceae (Bacteroidetes). In CO bioreactor, Proteobacteria bacteria decreased over time, while those of OLEI and GLYC bioreactors increased. A more pronounced increase in Bacteroidetes and Firmicutes were observed in CO bioreactor. The methanogenic archaea Methanobacteriaceae and Methanocorpusculaceae were identified. This analysis has shown that a set of microbial population is selected as a function of the substrate.
Competing Interests: The authors have declared that no competing interests exist.
Databáze: MEDLINE
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