Petroleum-based products are a primary energy source in the industry and daily life. During the exploration, processing, transport and storage of petroleum and petroleum products, water or soil pollution occurs regularly. Biodegradation of the hydrocarbon pollutants by indigenous microorganisms is one of the primary mechanisms of removal of petroleum compounds from the environment. However, the physical contact between microorganisms and hydrophobic hydrocarbons limits the biodegradation rate. This paper presents an updated review of the petroleum hydrocarbon uptake and transport across the outer membrane of microorganisms with the help of outer membrane proteins.

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Acute pancreatitis is an inflammatory process originated in the pancreas; however, it often leads to systemic complications that affect distant organs. Acute respiratory distress syndrome is indeed the predominant cause of death in patients with severe acute pancreatitis. In this study, we aimed to delineate the ameliorative effect of dihydro-resveratrol, a prominent analog of trans-resveratrol, against acute pancreatitis-associated lung injury and the underlying molecular actions. Acute pancreatitis was induced in rats with repetitive injections of cerulein (50 µg/kg/h) and a shot of lipopolysaccharide (7.5 mg/kg). By means of histological examination and biochemical assays, the severity of lung injury was assessed in the aspects of tissue damages, myeloperoxidase activity, and levels of pro-inflammatory cytokines. When treated with dihydro-resveratrol, pulmonary architectural distortion, hemorrhage, interstitial edema, and alveolar thickening were significantly reduced in rats with acute pancreatitis. In addition, the production of pro-inflammatory cytokines and the activity of myeloperoxidase in pulmonary tissues were notably repressed. Importantly, nuclear factor-kappaB (NF-κB) activation was attenuated. This study is the first to report the oral administration of dihydro-resveratrol ameliorated acute pancreatitis-associated lung injury via an inhibitory modulation of pro-inflammatory response, which was associated with a suppression of the NF-κB signaling pathway.

A strain of Pseudomonas sp. DG17, capable of degrading crude oil, was immobilized in sodium alginate–attapulgite–calcium carbonate for biodegradation of crude oil contaminated soil. In this work, proportion of independent variables, the laboratory immobilization parameters, the micromorphology and internal structure of the immobilized granule, as well as the crude oil biodegradation by sodium alginate–attapulgite–calcium carbonate immobilized cells and sodium alginate–attapulgite immobilized cells were studied to build the optimal immobilization carrier and granule-forming method. The results showed that the optimal concentrations of sodium alginate–attapulgite–calcium carbonate and calcium chloride were 2.5%–3.5%, 0.5%–1%, 3%–7% and 2%–4%, respectively. Meanwhile, the optimal bath temperature, embedding cell amount, reaction time and multiplication time were 50–60 °C, 2%, 18 h and 48 h, respectively. Moreover, biodegradation was enhanced by immobilized cells with a total petroleum hydrocarbon removal ranging from 33.56% ± 3.84% to 56.82% ± 3.26% after 20 days. The SEM results indicated that adding calcium carbonate was helpful to form internal honeycomb-like pores in the immobilized granules.

The trans-membrane transport of hydrocarbons is an important and complex aspect of the process of biodegradation of hydrocarbons by microorganisms. The mechanism of transport of (14)C n-octadecane by Pseudomonas sp. DG17, an alkane-degrading bacterium, was studied by the addition of ATP inhibitors and different substrate concentrations. When the concentration of n-octadecane was higher than 4.54 μmol/L, the transport of (14)C n-octadecane was driven by a facilitated passive mechanism following the intra/extra substrate concentration gradient. However, when the cells were grown with a low concentration of the substrate, the cellular accumulation of n-octadecane, an energy-dependent process, was dramatically decreased by the presence of ATP inhibitors, and n-octadecane accumulation continually increased against its concentration gradient. Furthermore, the presence of non-labeled alkanes blocked (14)C n-octadecane transport only in the induced cells, and the trans-membrane transport of n-octadecane was specific with an apparent dissociation constant K t of 11.27 μmol/L and V max of 0.96 μmol/min/mg protein. The results indicated that the trans-membrane transport of n-octadecane by Pseudomonas sp. DG17 was related to the substrate concentration and ATP.