文献类型：期刊文献

英文题名：Power input effects on degeneration in prolonged penicillin chemostat cultures: A systems analysis at flux, residual glucose, metabolite, and transcript levels

作者：Wang, Guan[1];Wu, Baofeng[1];Zhao, Junfei[1];Haringa, Cees[2];Xia, Jianye[1];Chu, Ju[1];Zhuang, Yingping[1];Zhang, Siliang[1];Heijnen, Joseph J.[3];van Gulik, Walter[3];Deshmukh, Amit T.[4];Noorman, Henk J.[4,5]

机构：[1]ECUST, State Key Lab Bioreactor Engn, Shanghai, Peoples R China;[2]Delft Univ Technol, Chem Engn Dept, Transport Phenomena, Delft, Netherlands;[3]Delft Univ Technol, Dept Biotechnol, Cell Syst Engn, Delft, Netherlands;[4]DSM Biotechnol Ctr, Delft, Netherlands;[5]Delft Univ Technol, Dept Biotechnol, Bio Proc Engn, Delft, Netherlands

年份：2018

卷号：115

期号：1

起止页码：114

外文期刊名：BIOTECHNOLOGY AND BIOENGINEERING

收录：;EI(收录号：20174804466012);WOS:【SCI-EXPANDED(收录号:WOS:000416114400010)】；

基金：National Basic Research Program, Grant number: 2013CB733600; NWO-MoST Joint Program, Grant number: 2013DFG32630

语种：英文

外文关键词：degeneration; glucose transport; power input; redox; energy metabolism; scale down

摘要：In the present work, by performing chemostat experiments at 400 and 600 RPM, two typical power inputs representative of industrial penicillin fermentation (P/V, 1.00kW/m(3) in more remote zones and 3.83kW/m(3) in the vicinity of the impellers, respectively) were scaled-down to bench-scale bioreactors. It was found that at 400 RPM applied in prolonged glucose-limited chemostat cultures, the previously reported degeneration of penicillin production using an industrial Penicillium chrysogenum strain was virtually absent. To investigate this, the cellular response was studied at flux (stoichiometry), residual glucose, intracellular metabolite and transcript levels. At 600 RPM, 20% more cell lysis was observed and the increased degeneration of penicillin production was accompanied by a 22% larger ATP gap and an unexpected 20-fold decrease in the residual glucose concentration (C-s,C-out). At the same time, the biomass specific glucose consumption rate (q(s)) did not change but the intracellular glucose concentration was about sixfold higher, which indicates a change to a higher affinity glucose transporter at 600 RPM. In addition, power input differences cause differences in the diffusion rates of glucose and the calculated Batchelor diffusion length scale suggests the presence of a glucose diffusion layer at the glucose transporting parts of the hyphae, which was further substantiated by a simple proposed glucose diffusion-uptake model. By analysis of calculated mass action ratios (MARs) and energy consumption, it indicated that at 600 RPM glucose sensing and signal transduction in response to the low C-s,C-out appear to trigger a gluconeogenic type of metabolic flux rearrangement, a futile cycle through the pentose phosphate pathway (PPP) and a declining redox state of the cytosol. In support of the change in glucose transport and degeneration of penicillin production at 600 RPM, the transcript levels of the putative high-affinity glucose/hexose transporter genes Pc12g02880 and Pc06g01340 increased 3.5- and 3.3-fold, respectively, and those of the pcbC gene encoding isopenicillin N-synthetase (IPNS) were more than twofold lower in the time range of 100-200hr of the chemostat cultures. Summarizing, changes at power input have unexpected effects on degeneration and glucose transport, and result in significant metabolic rearrangements. These findings are relevant for the industrial production of penicillin, and other fermentations with filamentous microorganisms.