Resumo
To facilitate the biodegradation of diesel oil, an oil biodegradation bacterial consortium was constructed. The alkane hydroxylase (alkB) gene of Pseudomonas putida GPo1 was constructed in a pCom8 expression vector, and the pCom8-GPo1 alkB plasmid was transformed into Escherichia coli DH5α. The AlkB protein was expressed by diesel oil induction and detected through SDS-polyacrylamide gel electrophoresis. The culture of the recombinant (pCom8-GPo1 alkB/E. coli DH5α) with the oil biodegradation bacterial consortium increased the degradation ratio of diesel oil at 24 h from 31% to 50%, and the facilitation rates were increased as the proportion of pCom8-GPo1 alkB. coli DH5α to the consortium increased. The results suggested that the expression of the GPo1 gene in E. coli DH5α could enhance the function of diesel oil degradation by the bacterial consortium.(AU)
Assuntos
Acinetobacter/metabolismo , Biodegradação Ambiental , Citocromo P-450 CYP4A/genética , Escherichia coli/metabolismo , Consórcios Microbianos/genética , Pseudomonas putida/enzimologia , Acinetobacter/genética , Escherichia coli/enzimologia , Escherichia coli/genética , Óleos Combustíveis , Gasolina , Engenharia Genética , Oxirredução , Plasmídeos/genética , Pseudomonas putida/genética , Pseudomonas putida/metabolismoResumo
Bacteria have evolved various mechanisms to extract utilizable substrates from available resources and consequently acquire fitness advantage over competitors. One of the strategies is the exploitation of cryptic cellular functions encoded by genetic systems that are silent under laboratory conditions, such as the bgl (β-glucoside) operon of E. coli. The bgl operon of Escherichia coli, involved in the uptake and utilization of aromatic β-glucosides salicin and arbutin, is maintained in a silent state in the wild type organism by the presence of structural elements in the regulatory region. This operon can be activated by mutations that disrupt these negative elements. The fact that the silent bgl operon is retained without accumulating deleterious mutations seems paradoxical from an evolutionary view point. Although this operon appears to be silent, specific physiological conditions might be able to regulate its expression and/or the operon might be carrying out function(s) apart from the utilization of aromatic β-glucosides. This is consistent with the observations that the activated operon confers a Growth Advantage in Stationary Phase (GASP) phenotype to Bgl+ cells and exerts its regulation on at least twelve downstream target genes.