276 Fig. 5 Effect of cumulative load of MC-processed food scrap amended into soil on the soil polysaccharide content at subsequent sampling. Each data point represents a different field site we examined. Processed residue amended in soil is the cumulative load of MC-processed food scrap added to the specific site tested and calculated from the area covered and amount of material added independent of amendment date within a 6-month interval since amend- ment commenced Appl Biochem Biotechnol (2011) 165:270–278 SOC content of soil. Aerated composting (AC), one of the most common routes for recycling organic C into soil, has undeniable economical and ecological advantages, but also has some notable shortcomings. Its C recycling potential is 50% or less, the entire process is long (≥6 months), and its GHG footprint is very large [10–13]. The main gas produced during AC is CO2, but CH4 (~25 times more potent as a GHG than CO2) is also a notable by-product. Along with C mineralization, N is also released, mostly as amines, heterocyclic compounds, ammonia, nitrite, and nitrate. Suboxic, acidic, and organic rich conditions can lead to incomplete denitrification with the formation of N2O as well [26, 27]. The amount of N2O emitted is small relative to CO2, yet N2O is ~300 times more powerful as a GHG than CO2 [28]. There is furthermore clear evidence that unchecked N2O produced during the turnover of C residues amended in soil can contribute GHG equivalents to the atmosphere which more than offset C savings due to AC [29]. The purpose of this work was to increase the C recycling potential and to minimize CH4 emission during MC of leaves and food scrap. MC uses microbial communities dominated by aerotolerant fermenters and microaerophiles (cellulolytic Gram-positive bacteria and yeasts). As practiced in this study, MC is less labor-intensive than AC; forced aeration and physically turning over the compost biomass, for example, are not required. MC also requires less time (about 2 weeks) to reach an end point. Since the combined loss of C at the end point is small (≤2%), most of the C processed ends up in soil. Furthermore, in MC fermentors, the pH shift Fig. 6 VOA gc tracing of aqueous extract of MC-processed food scrap amended soil sample (1:1, w/ww) obtained from soil 2 months after burial and aging of the processed feedstock in the field