Fig 1.
Biogas formation profile from cooking oil (CO) after modeling.
Cumulated volume of biogas formation during the anaerobic digestion of cooking oil (CO), modeled using the Gompertz equation.
Fig 2.
Rate of biogas formation from cooking oil (CO).
Rate of the biogas formation as a function of cooking (CO) oil concentrations. These values derived from the Gompertz equation. Values on top of each column indicate the maximum accumulated biogas produced (ml.L-1).
Fig 3.
Reduction rates of chemical oxygen demand (COD).
Reduction rates COD of a culture of 0.1 g L-1 of cooking oil (CO) in relation with biogas formation. Close squares represent cumulated biogas formation (as per the Gompertz equation), while open circles represent the COD reduction.
Table 1.
Biogas formation in different conditions.
Rate of biogas formation and the maximum cumulated volumes achieved during various conditions of pH, temperature and salinity of the consortium. These values derived from the Gompertz model equations. Cooking oil (CO) was used at 1g.L-1.
Fig 4.
Comparative rates of biogas formation between substrates.
Rate of biogas formation as a function of cooking oil (CO) and long chain fatty acids (STEA, stearic acid; PALM, palmitic acid; OLEI, oleic acid). These values derived from the Gompertz equation.
Fig 5.
Rate of biogas formation with glycerol (GLYC) as substrate.
Rate of biogas formation as a function of glycerol (GLYC) concentrations. These values derived from the Gompertz equation. Values (ml) on top of each column refer to the maximum volumes of the produced biogas.
Fig 6.
Microbial abundance in relation with species phyla.
Relative abundance of microbial phyla in the presence of cooking oil (CO), glycerol (GLYC), and oleic acid (OLEI), as a function of time (1, 5, and 15 days).
Fig 7.
Microbial abundance in relation with species classes.
Relative abundance of the class of microbes in the presence of cooking oil (CO), glycerol (GLYC), and oleic acid (OLEI), as a function of time (1, 5, and 15 days).
Fig 8.
Microbial abundance in relation with species families.
Relative abundance of the family of microbes in the presence of cooking oil (CO), glycerol (GLYC), and oleic acid (OLEI) as a function of time (1, 5, and 15 days).
Fig 9.
Chao1 and Shannon diversity indices.
Chao1 and Shannon indices depicting the α-diversity of microbial communities in cooking oil, glycerol, oleic acid bioreactors.
Fig 10.
Bray-Curtis principal coordinates analysis.
β-diversity of microbial community in CO, GLYC and OLEI bioreactors, as a function of time using the principal coordinates analysis of Bray-Curtis dissimilarity (PCoA).