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Table 1 Reactor setup, apparent LPMO activity and ratio between added H2O2 and generated oxidized products for reactions with Avicel

From: The impact of hydrogen peroxide supply on LPMO activity and overall saccharification efficiency of a commercial cellulase cocktail

H2O2 in feed (mM) H2O2 feed rate (µM h−1) LPMO activitya, 1 h (min−1) Cumulative [H2O2] after 6 h (µM)b [Glc4gemGlc] after 6 h (µM) [Product]/[H2O2] ratio after 6 h (%)c LPMO activitya, 6 h (min−1)
45 30 0.29 180 161.5 89.7 0.22
135 90 0.63 540 444.4 82.3 0.62
270 180 1.25 1080 947.5 87.7 1.32
450 300 2.02 1800 1394.2 77.5 1.94
900 600 4.13 3600 3018.2 83.8 4.19
4500 3000 15.05 18,000 2004.7 11.1 2.78
  1. aApparent LPMO turnover rates were calculated based on the assumption that 15% (w/w) of the proteins in Cellic® CTec2 is composed of LPMOs [16]. Avicel (10% w/w DM) was hydrolyzed with Cellic® CTec2 (4 mg protein/g DM), yielding a total protein concentration of 400 mg L−1, whereof LPMOs constitute 60 mg L−1, which equals 2 µM (using a molecular weight of 30,000 g mol−1). Turnover rates were estimated from the 1 and the 6 h points shown in Fig. 3a. Comparison of the 1 and 6 h rates shows that product formation was almost linear with time in these 6 h, except for the highest feed rate; see also Fig. 3a. Reactions were carried out in sodium acetate buffer (pH 5.0, 50 mM) at 50 °C, under stirring and continuous nitrogen sparging, using AscA (1 mM) as reductant
  2. bH2O2 concentration that would be measured in the bioreactor if added H2O2 would accumulate, assuming that nothing is consumed or produced by the LPMOs or by redox side reactions with AscA
  3. cThis column lists the Glc4gemGlc concentration as percentage of the cumulative hypothetical H2O2 concentration (see footnote b), after 6 h reaction. In the presence of cellulases, as in Cellic® CTec2, all C4-oxidized products are converted to Glc4gemGlc, and C1-oxidized products to gluconic acid and cellobionic acid. See text for more details
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