Design and applications of synthetic electroactive microbial consortia / 生物工程学报

Synthetic electroactive microbial consortia, which include exoelectrogenic and electrotrophic communities, catalyze the exchange of chemical and electrical energy in cascade metabolic reactions among different microbial strains. In comparison to a single strain, a community-based organisation that assigns tasks to multiple strains enables a broader feedstock spectrum, faster bi-directional electron transfer, and greater robustness. Therefore, the electroactive microbial consortia held great promise for a variety of applications such as bioelectricity and biohydrogen production, wastewater treatment, bioremediation, carbon and nitrogen fixation, and synthesis of biofuels, inorganic nanomaterials, and polymers. This review firstly summarized the mechanisms of biotic-abiotic interfacial electron transfer as well as biotic-biotic interspecific electron transfer in synthetic electroactive microbial consortia. This was followed by introducing the network of substance and energy metabolism in a synthetic electroactive microbial consortia designed by using the "division-of-labor" principle. Then, the strategies for engineering synthetic electroactive microbial consortiums were explored, which included intercellular communications optimization and ecological niche optimization. We further discussed the specific applications of synthetic electroactive microbial consortia. For instance, the synthetic exoelectrogenic communities were applied to biomass generation power technology, biophotovoltaics for the generation of renewable energy and the fixation of CO2. Moreover, the synthetic electrotrophic communities were applied to light-driven N2 fixation. Finally, this review prospected future research of the synthetic electroactive microbial consortia.

Association between gallstones and metabolic syndrome in southern Xinjiang, China / 临床肝胆病杂志

Objective To investigate the association between gallstones (GS) and metabolic syndrome (MS) in southern Xinjiang, China, and to provide experience for the prevention and control of metabolic diseases in southern Xinjiang. Methods The patients with GS who visited First Division Hospital, Second Division Korla Hospital, and Third Division Hospital of Xinjiang Production and Construction Corps from March 2015 to March 2019 were enrolled as case group, and cluster sampling was used to select the individuals who underwent physical examination in Third Division 51st Regiment Hospital during the same period of time were enrolled as control group. According to inclusion and exclusion criteria, 1140 cases were enrolled in each group after 1∶ 1 matching based on age and sex. The t -test was used for comparison of continuous data between two groups, and the chi-square test was used for comparison of categorical data between two groups; a logistic regression analysis was used to investigate the influencing factors for GS. Dummy variables were included by logistic regression to evaluate multiplicative interaction between MS components, and the parameter estimate and covariance matrix of the logistic regression model and interaction calculation table were used to calculate and evaluate additive interaction between MS components. Results The risk of GS in MS patients was 2.33 times that in non-MS patients (odds ratio [ OR ]=2.33, 95% confidence interval [ CI ]: 1.86-2.92). In addition, the components of MS also increased the risk of GS, including blood glucose ( OR =2.94, 95% CI : 2.36-3.68), blood pressure ( OR =1.50, 95% CI : 1.26-1.80), blood lipids ( OR =1.48, 95% CI : 1.25-1.75), and body mass index ( OR =1.44, 95% CI : 1.21-1.70). After adjustment for multiple factors, the risk of GS gradually increased with the increase in the number of metabolic abnormalities, i.e., one abnormality ( OR =1.55, 95% CI : 1.22-1.99), two abnormalities ( OR =2.13, 95% CI : 1.66-2.72), three abnormalities ( OR =3.48, 95% CI : 2.59-4.69), and four abnormalities ( OR =4.65, 95% CI : 2.79-7.84). No additive or multiplicative interaction was found between MS components. Conclusion GS is closely associated with MS in southern Xinjiang, and the risk of GS gradually increases with the increase in MS components. No additive or multiplicative interaction is found between GS and MS components.

Progress in enhancing electron transfer rate between exoelectrogenic microorganisms and electrode interface / 生物工程学报

Exoelectrogenic microorganisms are the research basis of microbial electrochemical technologies such as microbial fuel cells, electrolytic cells and electrosynthesis. However, their applications are restricted in organic degradation, power generation, seawater desalination, bioremediation, and biosensors due to the weak ability of biofilm formation and the low extracellular electron transfer (EET) efficiency between exoelectrogenic microorganisms and electrode. Therefore, engineering optimization of interaction between exoelectrogenic microorganisms and electrode interface recently has been the research focus. In this article, we review the updated progress in strategies for enhancing microbe-electrode interactions based on microbial engineering modifications, with a focus on the applicability and limitations of these strategies. In addition, we also address research prospects of enhancing the interaction between electroactive cells and electrodes.

Research progress in screening method of exoelectrogens / 生物工程学报

Exoelectrogens are promising for a wide variety of potential applications in the areas of environment and energy, which convert chemical energy from organic matter into electrical energy by extracellular electrons transfer (EET). Microorganisms with different mechanisms and EET efficiencies have been elucidated. However, the practical applications of exoelectrogens are limited by their fundamental features. At present, it is difficult to realize the extensive application of exoelectrogens in complex and diverse environments by means of traditional engineering strategies such as rational design and directed evolution. The exoelectrogens with excellent performance in environments can be screened with efficient strain identification technologies, which promote the widespread applications of exoelectrogens. The aims of this review are to summarize the methods of screening based on different types of exoelectrogens, and to outline future research directions of strain screening.