This paper describes purported extracellular metabolism of 13C-enriched glucose which was demonstrated in sterilized soils. The exact mechanism is still uncertain but the manuscript presents potential explanations for the observations. Two referees have provided excellent suggestions for further refinement of the manuscript which should be followed to improve the impact and clarity. The authors are encouraged to incorporate all of the suggestions by the referees, and to additionally proofread the manuscript carefully.

The authors have addressed the concerns of the two reviewers and the manuscript is now nearly ready for publication. My main question that remains is how the proportion of DOC oxidized to CO2 changes with treatment (i.e., divide CO2 production rate by DOC content). The DOC increases with duration of autoclaving but does the CO2 emission rate increase proportionally? This could be one more useful piece of information to help interpret the purported isotopic fractionation effects and their dependence on DOC concentration. See my comments on Fig 3 and suggestions for including this in the discussion section.
Specific comments:
Line 31: and line 379: remove “to” so it reads “do not likely obey the same…”
Line 56: and line 291: change “glucose in…” to “glucose to…” and line 292, “oxidized to”
Lines 109-110: I don’t think “mn” is an accepted abbreviation for minutes, rather use “min”. Also 30 mn^-1 would more commonly be 0.5 Hz (one measurement per 2 seconds).
Line 130: Is FC flow cytometry? Please spell out on first use.
Line 219-221 etc: Please remove the unnecessary abbreviation DER.
Line 229: Has a mass balance been done on the DOC and CO2? Probably the amount of CO2 release was too small to make a change in the large DOC pool, but it would be useful to know what % of the DOC was cumulatively respired (similar to your estimate for the % of glucose input on lines 241-242).
Lines 268-284: Consider discussing the amount of CO2 respired per unit of DOC in this section (see comments on Fig 3). Of course, this will be highest in LS and lower in the others, but from Figure 3a and 3c it’s not clear how the other treatments will affect the efficiency of C respiration. How does this change the argument about the fractionation effect of EXOMET? Or, this could be discussed in the section on lines 304-318.
Line 395: change to “before they were incorporated in the first cell.”
Figure 1: This is a helpful figure, however it needs to be edited to change the figure numbers within it, because perhaps it was prepared as a supplemental figure initially; change Fig 1a to 2a, etc.
Figure 3: What are the units on 3c? This figure would look really different if presented per unit of DOC.
Figure 4: The caption says 32 days but bar graph label says 34 days.