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Background: Yarrowia lipolytica is considered as a promising biorefinery chassis for production of microbial lipids, the important precursors of advanced biofuels. Unfortunately, wild Yarrowia lipolytica is unable to consume xylose, the major pentose in lignocellulosic hydrolysates. A recombinant strain Yarrowia lipolytica yl-XYL+ can utilize xylose to produce microbial lipids efficiently, but its xylose uptake is severely delayed in the presentence of D-glucose. Therefore, it is critical to develop cofermenting D-glucose and xylose strains and study the underlying mechanisms. Results: In this study, an adaptive laboratory evolution (ALE) is performed to engineering the strains in the medium containing xylose and D-glucose analog 2-deoxyglucose (dG). After four stages of evolution over a total of 64 days, we obtained for the first time a strain of Y. lipolytica (yl-XYL+*04*10) with derepressed xylose metabolism. Xylose uptake kinetics showed that it could efficiently utilize xylose in the presence of 10 g/L dG or D-glucose. Transcriptional profiling analysis revealed that relative expression level of YALI0_C04730g and YALI0_D00363g (both encoding xylosespecific transporter) was significantly up-regulated. Besides, we found that missense mutations N373T and G270A in YALI0_E23287g (encoding a D-glucose transporter) and YALI0_E15488g (encoding a hexokinase) respectively. Conclusions: These results indicate that these are important gene targets responsible for improved xylose utilization in the evolved Yarrowia lipolytica. Our work provides a new approach for breeding Yarrowia lipolytica and paved the way for future pentose metabolic engineering.

The large-scale penetration of renewable energy and deeply integrated multiple energy forms pose a major challenge for the accounting and allocation process of additional adjustment cost in multi-energy system and electricity market. The variable wind power and the operating status of multi-energy systems faced by the electricity market have driven researchers towards the decision of electricity spot market with complicated pricing mechanism. This paper presents a locational marginal price-based partition optimal economic dispatch model of multi-energy system with a high proportion of renewable energy. First, a model of the additional adjustment cost of multi-energy adjustable units to improve the power grid adjustment capacity is studied based on the power balance model of multi-energy conversion and storage. In the second, to improve the effectiveness of the ESM mechanism, an optimal economic dispatch model is established, with the goal of minimizing the additional adjustment cost of multi-energy adjustable units. Moreover, according to the characteristics of the model and the mechanism of locational marginal price-based economic dispatch, a solution method based on lagrangian relaxation is proposed. The incentive compatible locational marginal price is obtained. Finally, a simulation model of multi-energy systems based on IEEE 39-nodes power system and 7-nodes natural gas system is established. And the model is based on operating data of an actual grid with high proportion of renewable energy in Northeast China. The results of the examples show that the proposed method can effectively improve the efficiency and flexibility of multi-energy system. Another advantage of the proposed method is that the capabilities of the complementary multi-energy coordination can be promoted.