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Petroleum and fuel oil are complex mixtures of recalcitrant hydrocarbons. The biodegradation of these hydrocarbons needs the action of a vast variety of enzymatic capacities. A microbial consortium offers the capability to degrade complex substrates through the assembly of different biochemical reactions, providing a metabolic versatility superior to axenic cultures. In this work, the microbial population dynamics, taxonomy, and the catabolic capacity of a stabilized consortium exposed to fuel and crude oil was analyzed through metagenomics. The stabilized consortium degraded 59% of crude oil components after 8 days, and 34% of fuel oil components after 130 days. Population dynamics analysis indicates that in fuel oil the biodiversity richness was higher; however, denaturing gradient gel electrophoresis similarity dendrogram shows significant changes in the microbial population during crude oil degradation. Taxonomy studies indicate a great genera divergence; only eight microbial genera were common in both samples. In crude oil, the Limnobacter sp. was the most abundant specie (15.6%), while Sphingomonas wittichii (7.9%) and Novosphingobium aromaticivorans (7.6%) were abundant in fuel oil. These microorganisms have been reported to participate in the degradation of aliphatic and aromatic hydrocarbons. Functional analysis suggests that fuel and crude oil components changed the interactions between the consortium members affecting the collective metabolic functionality. [ABSTRACT FROM AUTHOR]

Hydrogen (H) production from the organic fraction of solid waste such as fruit and vegetable waste (FVW) is a novel and feasible energy technology. Continuous application of this process would allow for the simultaneous treatment of organic residues and energy production. In this study, batch experiments were conducted using glucose as substrate, and data of H production obtained were successfully adjusted by a logistic model. The kinetic parameters ( μ = 0.101 h, K = 2.56 g/L) of an H-producing microbial culture determined by the Monod and Haldane-Andrews growth models were used to establish the continuous culture conditions. This strategy led to a productive steady state in continuous culture. Once the steady state was reached in the continuous reactor, a maximum H production of 700 mL was attained. The feasibility of producing H from the FVW obtained from a local market in Mexico City was also evaluated using batch conditions. The effect of the initial FVW concentration on the H production and waste organic material degradation was determined. The highest H production rate (1.7 mmol/day), the highest cumulative H volume (310 mL), and 25 % chemical oxygen demand (COD) removal were obtained with an initial substrate (FVW) concentration of 37 g COD/L. The lowest H production rates were obtained with relatively low initial substrate concentrations of 5 and 11 g COD/L. The H production rates with FVW were also characterized by the logistic model. Similar cumulative H production was obtained when glucose and FVW were used as substrates. [ABSTRACT FROM AUTHOR]