A Single-Culture Bioprocess of Methanothermobacter thermautotrophicus to Upgrade Digester Biogas by CO₂-to-CH₄ Conversion with H₂

Table 2

Average volumetric methane production rates and hydrogen conversion efficiencies for Experiment 1. Averages were taken for experimental values in Figure 2 at each hydrogen influent rate from 3 or 4 days. Standard deviations (SD) were calculated based on the values used to calculate the average.

H2 influent rate (L/min) (𝑉H2)	0.1	0.2	0.4	0.8	1.6
Number of data points	𝑛=3	𝑛=3	𝑛=4	𝑛=3	𝑛=3
Average VMPR (L/L culture-day)	9.93	18.5	34.0	47.9	40.4
SD	0.16	0.87	0.42	1.40	2.53
Average H2 conversion efficiency	96.6%	89.9%	82.7%	58.2%	24.5%
SD	1.60%	4.23%	1.02%	1.70%	1.54%