## 3 Results and Discussion
### Microbiome Characterization of BSG and SCG  
As can be seen in Table 3, the total plate counts (TPCs) depend strongly on the source of the solid sidestream, with those obtained directly from the craft brewery and cafe having low bacteria TPCs, 3.53 \(\pm\) 0.03 log\({}_{10}\) CFU/g for BSG and not detectable at a level of 1 log\({}_{10}\) CFU/g for SCG, and no detectable fungi. This is in stark contrast with the solid sidestream from recycling facilities especially having high bacterial TPCs of more than 6 log\({}_{10}\) CFU/g and one SCG sample having a fungal TPC of 1.94 \(\pm\) 0.00 log\({}_{10}\) CFU/g. The presumed cause is the longer overnight storage time under ambient conditions at the recycling facilities prior to collection and testing and may be accelerated by opportunistic colonization of microorganisms from the environment, such as during transport from the production site to the recycling facility. The pH of BSG spans a range from 3.7 to 6.0 and decreases in proportion to the measured TPC. This indicates that BSG is only slightly acidic on lautering but is rapidly colonized by acid-producing bacteria, such as lactic acid bacteria (LAB), further lowering the pH. The TPC of BSG-1 from the craft brewery is about 3 orders of magnitude lower than that from the recycling facilities and therefore is expected to be more representative of the microbial load expected from BSG fresh from the brewery lauter tun. The pH of SCG falls in a narrow range of 4.8 to 5.9, without a clear link between pH and TPC. As stated, high bacterial TPCs of 6.16 \(\pm\) 0.02 and 7.70 \(\pm\) 0.02 log\({}_{10}\) CFU/g were found in the SCGs from the recycling facility, while SCG-1 from the cafe had significantly lower TPCs below the limit of detection of 1 log\({}_{10}\) CFU/g. The microorganisms isolated and identified from BSG are listed in Table 4. BSG contains the LAB genera _Pedicococcus_, _Enterococcus_, and _Limosilatobacillus_, all facultative anaerobic thermotolerant non-spore-forming bacteria ([PERSON] et al., 2018). _Pedicococcus_ spp. are associated with beer spoilage ([PERSON] et al., 2018), with _P. acidilacti_ specifically found in a craft brewery ([PERSON] et al., 2018), while _E. durans_ is a sour milk starter culture ([PERSON] et al., 2018) and _L. fermentum_ is a common spoilage microorganism in tomato products ([PERSON] et al., 2018). Faculative anaerobic spore-forming bacteria of the genus _Bacillus_ and non-spore-forming but desiccation-resistant _Citronobacter_([PERSON] et al., 2018) were also \begin{table}
\begin{tabular}{c c c c c c c} \hline  & **Chemical Analysis (fwb 1)** & **Elemental Analysis (dwb 2)** & **Total Plate Count (log\({}_{10}\) CFU/g (fwb 1)**)** \\ \hline
**Sample** & **Moisture** & **pH** & **TC 3** & **TN 4** & **Bacteria** & **Fungi** \\ \hline BSG-1 & 65\% & 6.0 & 43.3\% & 2.43\% & 3.53 \(\pm\) 0.03 & \textless{}1 \\ BSG-2 & 70\% & 4.7 & 46.1\% & 2.80\% & 7.42 \(\pm\) 0.02 & \textless{}1 \\ BSG-3 & 72\% & 3.7 & 55.4\% & 3.76\% & 7.07 \(\pm\) 0.08 & \textless{}1 \\ Average & 69 \(\pm\) 4\% & 4.8 \(\pm\) 1.1 & 48 \(\pm\) 6.3\% & 3.0 \(\pm\) 0.7\% & 6.0 \(\pm\) 1.9 & \textless{}1 \\ \hline SCG-1 & 64\% & 5.1 & 55.1\% & 2.14\% & \textless{}1 & \textless{}1 \\ SCG-2 & 56\% & 5.8 & 50.6\% & 2.38\% & 7.70 \(\pm\) 0.02 & \textless{}1 \\ SCG-3 & 48\% & 4.8 & 43.2\% & 1.71\% & 6.16 \(\pm\) 0.02 & 1.94 \(\pm\) 0.00 \\ Average & 56 \(\pm\) 8\% & 5.2 \(\pm\) 0.5 & 49.6 \(\pm\) 6.0\% & 2.1 \(\pm\) 0.3\% & 4.6 \(\pm\) 3.6 & 0.65 \(\pm\) 1.00 \\ \hline \end{tabular}  
* Fresh weight basis. 2 Dry weight basis. 3 Total carbon; 4 Total nitrogen.  
\end{table} 
Table 3: Chemical and elemental analysis and total plate counts for BSG and SCG solid sidestreams. identified. _B. subtilis_ is found in soil and fermented and dried foods such as _natto_ and milk products [46; 47; 48]; similarly, _B. rugosus_[46] is found in soil, and _C. malonicticus_ in milk products [45].