High-Yield Synthesis of Lacto-N-Neotetraose from Glycerol and Glucose in Engineered Escherichia coli.

Lacto-N-neotetraose (LNnT) is a neutral human milk oligosaccharide with important biological functions. However, the low LNnT productivity and the incomplete conversion of the intermediate lacto-N-tetraose II (LNT II) currently limited the sustainable biosynthesis of LNnT. First, the LNnT biosynthetic module was integrated in Escherichia coli. Next, the LNnT export system was optimized to alleviate the inhibition of intracellular LNnT synthesis. Furthermore, by utilizing rate-limiting enzyme diagnosis, the expressions of LNnT synthesis pathway genes were finely regulated to further enhance the production yield of LNnT. Subsequently, a strategy of cofermentation using a glucose/glycerol (4:6, g/g) mixed feed was employed to regulate carbon flux distribution. Finally, by overexpressing key transferases, LNnT and LNT II titers reached 112.47 and 7.42 g/L, respectively, in a 5 L fermenter, and 107.4 and 2.08 g/L, respectively, in a 1000 L fermenter. These are the highest reported titers of LNnT to date, indicating its significant potential for industrial production.

Does Industrial Agglomeration or Foreign Direct Investment Matter for Environment Pollution of Public Health? Evidence From China.

This article focuses on the interaction between China's industrial agglomeration, foreign direct investment (FDI) and environmental pollution of public health in the past 15 years. By conducting theoretical and empirical research, we try to reveal the relationship and mechanism between the economic growth and public health from the perspective of environmental pollution. By constructing an embedded theoretical model of industrial agglomeration and FDI, this article combines other environmental pollution influencing factors, expounds the impact mechanism of industrial agglomeration on environmental pollution. Based on the provincial-level panel data of China on environmental pollution and industrial agglomeration, the empirical test is carried out through the threshold panel regression model. According to the results, industrial agglomeration can significantly rectify the regional environmental pollution, thereby benefiting public health. FDI has a phased impact on the relationship between industrial agglomeration and environmental pollution. Specifically, when the level of FDI is low, the positive improvement effect of industrial agglomeration on environmental pollution is relatively strong. This is mainly because industrial agglomeration can promote economic growth, technological progress, and enhance environmental awareness. When the level of FDI exceeds the first threshold and continues to rise, the positive improvement effect of industrial agglomeration is maximized. Before the level of FDI exceeds the second threshold, this effect gradually weakens. The population concentration and excessive expansion of city scale brought about by industrial agglomeration will lead to the increase of regional resource and energy consumption, thus aggravating environmental pollution. The policy implication is that while the government and enterprises are vigorously increasing the level of foreign investment, they must pay equal attention to economic growth and public health, and the level of industrial agglomeration should match the level of foreign investment so as to give full play to the positive improvement effect of industrial agglomeration on environmental pollution, and realize the coordinated development of the regional economy, environment and population health.

Impact of industrial agglomeration on environmental pollution from perspective of foreign direct investment-a panel threshold analysis for Chinese provinces.

In the course of China's rapid economic development, the coexistence of industrial development and dominant industrial agglomeration (AGG), along with growing environmental problems, has attracted widespread attention from scholars. Although the linear relationship between the two has been analyzed in depth in the research literature, a concomitant phenomenon, i.e., the gradual expansion in the scale of foreign direct investment (FDI), has been overlooked. By employing threshold panel regression model, this paper attempts to construct a theoretical model with embedded AGG and FDI, and incorporates other factors affecting environmental pollution (POL). For examining the mechanism of AGG on POL, we proposed a testable theoretical hypothesis, and conducted an empirical study by combining panel data of POL and AGG at the provincial level in China. The measurement index of a control variable was changed to check the robustness of our results, and the coefficient sign of each explanatory variable was not changed, confirming the robustness of main results. Overall, AGG improves regional POL, but the impact of FDI is stage-specific and roughly there are three stages. Specifically, the positive effect of AGG on POL is strong when FDI is at a low level. When the level of FDI crosses the first threshold and continues to rise, the positive effect of AGG on POL reaches its strongest; until the second threshold is crossed, the positive effect of AGG starts diminishing slowly. Concluding this, for promoting economic development and environmental protection in the region in parallel, government and enterprises should prioritize the increment in FDI, with an equalization of levels of AGG and FDI, in order to enhance the improvement effect of AGG on POL.