Computer-Aided Rational Design of Efficient NADPH Production System by Escherichia coli pgi Mutant Using a Mixture of Glucose and Xylose

Abstract

Lignocellulosic biomass can be hydrolyzed into two major sugars of glucose and xylose, and thus the strategy for the efficient consumption of both sugars is highly desirable. NADPH is the essential molecule for the production of industrially important valueadded chemicals, and thus its availability is quite important. Escherichia coli mutant lacking the pgi gene encoding phosphoglucose isomerase (Pgi) has been preferentially used to overproduce the NADPH. However, there exists a disadvantage that the cell growth rate becomes low for the mutant grown on glucose. This limits the efficient NADPH production, and therefore, it is quite important to investigate how addition of different carbon source such as xylose (other than glucose) effectively improves the NADPH production. In this study, we have developed a kinetic model to propose an efficient NADPH production system using E. coli pgi-knockout mutant with a mixture of glucose and xylose. The proposed system adds xylose to glucose medium to recover the suppressed growth of the pgi mutant, and determines the xylose content to maximize the NADPH productivity. Finally, we have designed a mevalonate (MVA) production system by implementing ArcA overexpression into the pgi-knockout mutant using a mixture of glucose and xylose. In addition to NADPH overproduction, the accumulation of acetyl-CoA (AcCoA) is necessary for the efficient MVA production. In the present study, therefore, we considered to overexpress ArcA, where ArcA overexpression suppresses the TCA cycle, causing the overflow of AcCoA, a precursor of MVA. We predicted the xylose content that maximizes the MVA production. This approach demonstrates the possibility of a great progress in the computer-aided rational design of the microbial cell factories for useful metabolite production.

NADPH-dependent ROS accumulation contributes to the impaired osteogenic differentiation of periodontal ligament stem cells under high glucose conditions

“…Interestingly, although no significant change was found in total NADP levels, PDLSCs incubated under high glucose conditions exhibited a significant reduction in NADP + levels and an increase in NADPH levels and the NADPH/NADP + ratio ( Figure 2C ), indicating an increased NADPH production in cells under high glucose conditions. These results were consistent with previous studies suggesting that glucose is a main source of NADPH production and increasing glucose concentration can acutely promote NADPH generation from NADP + and increase intracellular NADPH levels ( 51 , 52 ). Ying et al.…”

Engineering Electron Transfer Pathway of Cytochrome P450s

“…Because the natural cofactor NAD(P)H is widely involved in various metabolic reactions in the cell, a change in its concentration in the cell will cause disturbances to cell life activities [ 46 ]. Therefore, unnatural cofactors such as nicotinamide cytidine dinucleotides (NCD) [ 47 ] and nicotinamide mononucleotides (NMN) were designed to be coupled to oxidoreductases [ 48 ].…”