With the development of metabolic engineering, employment of a selected microbial host for accommodation of a designed biosynthetic pathway to produce a target compound has achieved tremendous ...success in the past several decades. Yet, increasing requirements for sophisticated microbial biosynthesis call for establishment and application of more advanced metabolic engineering methodologies. Recently, important progress has been made towards employing more than one engineered microbial strains to constitute synthetic co-cultures and modularizing the biosynthetic labor between the co-culture members in order to improve bioproduction performance. This emerging approach, referred to as modular co-culture engineering in this review, presents a valuable opportunity for expanding the scope of the broad field of metabolic engineering. We highlight representative research accomplishments using this approach, especially those utilizing metabolic engineering tools for microbial co-culture manipulation. Key benefits and major challenges associated with modular co-culture engineering are also presented and discussed.
•Use of microbial co-culture composed of different strains is a robust method for microbial biosynthesis.•Modularization of biosynthetic pathways can be conducted in the context of microbial co-cultures.•Modular co-culture engineering takes advantage of both pathway modularization and microbial co-cultures.•Modular co-culture engineering has great potential for wide application in the field of metabolic engineering.•Disadvantages of this emerging approach need to be overcome for future development.
Holmes Rolston, III examined the significance of Asian thought for Western evaluations of nature and questioned if Asian Romanticism can inform the realistic decision making required for practice. ...However, Rolston’s general evaluation of Asian thought ignored Confucianism. This study launches a dialogue between Rolston and contemporary Confucianism on environmental philosophy and highlights the following points in response to Rolston: First, Confucianism is grounded on an “anthropocosmic” worldview and bases its environmental ethics on its affirmation of the “virtue of life and growth” and the related vision of “unity of heaven and human beings”; it is thus an objective environmental virtue ethics with the characteristics of sacred humanism that avoids anthropocentrism. Second, Confucian ethics is built on the premise of “one principle with various manifestations” and advocates for practicing benevolence through “love with gradations”, which avoids an excessively idealistic ecocentrism. Furthermore, Confucianism may adopt Rolston’s recommendation for Asian thought concerning the incorporation of evolutionary biology into Asian traditions to facilitate their own transformation and thus contribute to environmental philosophy. Upon an exploration of the compatibility and possible reciprocal illumination between Confucianism and Rolston, this paper points out the implications of the above dialogue for theology in the planetary climate crisis.
Pathway balancing is a critical and common challenge for microbial biosynthesis using metabolic engineering approaches. Non-linear biosynthetic pathways, such as diverging and converging pathways, ...are particularly difficult for bioproduction optimization, because they require delicate balancing between all interconnected constituent pathway modules. The emergence of modular co-culture engineering offers a new perspective for biosynthetic pathways modularization and balancing, as the biosynthetic capabilities of individual pathway modules can be coordinated by flexible adjustment of the subpopulation ratio of the co-culture strains carrying the designated modules. This study developed microbial co-cultures composed of multiple metabolically engineered E. coli strains for heterologous biosynthesis of complex natural product rosmarinic acid (RA) whose biosynthesis involves a complex diverging-converging pathway. Our results showed that, compared with the conventional mono-culture strategy, the engineered two-strain co-cultures significantly improved the RA production. Further pathway modularization and balancing in the context of three-strain co-cultures resulted in additional production improvement. Moreover, metabolically engineered co-culture strains utilizing different carbon substrates were recruited to improve the three-strain co-culture stability. The optimized co-culture based on these efforts produced 172 mg/L RA, exhibiting 38-fold biosynthesis improvement over the parent strain used in mono-culture biosynthesis. The findings of this work demonstrate the strong potentials of modular co-culture engineering for overcoming the challenges of complex natural product biosynthesis involving non-linear pathways.
•De novo biosynthesis of natural product rosmarinic acid was achieved in engineered E. coli.•Two-strain and three-strain E. coli co-cultures were developed for balancing the non-linear biosynthetic pathways.•Utilization of mixed carbon substrates improved the co-culture stability and biosynthetic performance.•Rosmarinic acid bioproduction by the optimized three-strain co-culture was 38-fold higher than that of the mono-culture.
Mercury (Hg) exposure poses substantial risks to human health. Investigating a longer chain from economic activities to human health can reveal the sources and critical processes of Hg-related health ...risks. Thus, we develop a more comprehensive assessment method which is applied to mainland China-the largest global Hg emitter. We present a map of Hg-related health risks in China and estimate that 0.14 points of per-foetus intelligence quotient (IQ) decrements and 7,360 deaths from fatal heart attacks are related to the intake of methylmercury in 2010. This study, for the first time, reveals the significant impacts of interprovincial trade on Hg-related health risks across the whole country. For instance, interprovincial trade induced by final consumption prevents 0.39 × 10
points for per-foetus IQ decrements and 194 deaths from fatal heart attacks. These findings highlight the importance of policy decisions in different stages of economic supply chains to reduce Hg-related health risks.
Engineering microbial consortia to express complex biosynthetic pathways efficiently for the production of valuable compounds is a promising approach for metabolic engineering and synthetic biology. ...Here, we report the design, optimization, and scale-up of an Escherichia coli - E. coli coculture that successfully overcomes fundamental microbial production limitations, such as high-level intermediate secretion and low-efficiency sugar mixture utilization. For the production of the important chemical cis , cis -muconic acid, we show that the coculture approach achieves a production yield of 0.35 g/g from a glucose/xylose mixture, which is significantly higher than reported in previous reports. By efficiently producing another compound, 4-hydroxybenzoic acid, we also demonstrate that the approach is generally applicable for biosynthesis of other important industrial products.
Rapid progress has been made in quantum secure direct communication in recent years. For practical application, it is important to improve the performances, such as the secure information rate and ...the communication distance. In this paper, we report an elaborate physical system design and protocol with much enhanced performance. This design increased the secrecy capacity greatly by achieving an ultra-low quantum bit error rate of <0.1%, one order of magnitude smaller than that of existing systems. Compared to previous systems, the proposed scheme uses photonic time-bin and phase states, operating at 50 MHz of repetition rate, which can be easily upgraded to over 1 GHz using current on-the-shelf technology. The results of our experimentation demonstrate that the proposed system can tolerate more channel loss, from 5.1 dB, which is about 28.3 km in fiber in the previous scheme, to 18.4 dB, which corresponds to fiber length of 102.2 km. Thus, the experiment shows that intercity quantum secure direct communication through fiber is feasible with present-day technology.
With the advent of the 5G era, various thermal conductivity nanocomposites are being investigated to solve the heat accumulation on the surface of electronic devices. In this study, magnetic ...nanofiller ferroferric oxide-polydopamine-boron nitride nanosheets (Fe-PDA-BNNSs) are fabricated by mussel-inspired and coprecipitation methods with polydopamine (PDA) and ferroferric oxide (Fe
3
O
4
). The aligned Fe-PDA-BNNSs/poly(vinyl alcohol) (PVA) composites with higher in-plane thermal conductivity and decent mechanical properties are prepared by applying a horizontal magnetic field. The in-plane thermal conductivity of the aligned composite at 30 wt% filler loading reaches 5.237 W/(m·K), which is 1.1 times and 20.5 times that of the unaligned composites and neat PVA. Moreover, the aligned composite maintains mechanical strength and obtains commendable thermal stability and heat dissipation capability, which can be applied to the thermal management of flexible electronic devices.
3‐amino‐benzoic acid (3AB) is an important building block molecule for production of a wide range of important compounds such as natural products with various biological activities. In the present ...study, we established a microbial biosynthetic system for de novo 3AB production from the simple substrate glucose. First, the active 3AB biosynthetic pathway was reconstituted in the bacterium Escherichia coli, which resulted in the production of 1.5 mg/L 3AB. In an effort to improve the production, an E. coli‐E. coli co‐culture system was engineered to modularize the biosynthetic pathway between an upstream strain and an downstream strain. Specifically, the upstream biosynthetic module was contained in a fixed E. coli strain, whereas a series of E. coli strains were engineered to accommodate the downstream biosynthetic module and screened for optimal production performance. The best co‐culture system was found to improve 3AB production by 15 fold, compared to the mono‐culture approach. Further engineering of the co‐culture system resulted in biosynthesis of 48 mg/L 3AB. Our results demonstrate co‐culture engineering can be a powerful new approach in the broad field of metabolic engineering.
This study aims to establish a novel biosynthetic system for production of important molecule 3‐amino‐benzoic acid from the simple substrate glucose. The biosynthetic pathway was accommodated in a microbial co‐culture composed of two E. coli strains responsible for the upstream and downstream pathway modules, respectively. This approach allowed for rapid identification of the best combination of the constituent E. coli strains and resulted in the production of 48 mg/L 3‐amino‐benzoic acid.
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