## 3 Results
### Microbial Community \(\alpha\)-Diversity and \(\beta\)-Diversity between S- and N-NXDQ  
An average of 24,227 bacterial valid sequences and 69,960 fungal valid sequences were found per _daqu_ sample after quality filtering, denoising, removing chimeras and sequence leveling. Then, along with 350 and 522 fungal OUTs for S and N-NXDQ, 920 and 711 bacterial OUTs were obtained, respectively. The Sobs, Chao and Shannon index, as \(\alpha\)-diversity indices, reflected the observed species, community richness and community diversity, respectively. As shown in Figure 2, the bacterial Sobs and Chao indexes of S-NXDQ were significantly higher than that of N-NXDQ (Figure 2a), while two indexes of fungi were the opposite (Figure 2b). The bacterial Shannon index was not significantly  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**NXDQ**} & \multirow{2}{*}{**Sample**} & \multirow{2}{*}{**Moisture (\%)**} & \multirow{2}{*}{**Acidity**} & \multirow{2}{*}{**Liquifying**} & \multicolumn{2}{c}{**Saccharification**} & \multicolumn{2}{c}{**Esterifying**} & \multicolumn{1}{c}{**Fert**} \\  & & & & **(mmol/10 g)** & & **Power** & **Power** & **Power** \\  & & & & (g/g-h) & (mg/g-h) & (mg/g-h) & (mg/g-100 h) & (gCO2/g-72 h) \\ \hline S-NXDQ & MSH\_S & 11.30 \(\pm\) 0.49 \({}^{\circ}\) & 0.60 \(\pm\) 0.07 \({}^{\circ}\) & 2.34 \(\pm\) 0.06 \({}^{\circ}\) & 366.00 \(\pm\) 50.91 \({}^{\circ}\) & 27.74 \(\pm\) 1.73 \({}^{\circ}\) & 0.49 \(\pm\) 0.01 \({}^{\circ}\) \\  & MYP\_S & 11.80 \(\pm\) 0.07 \({}^{\circ}\) & 1.70 \(\pm\) 0.02 \({}^{\circ}\) & 3.85 \(\pm\) 0.11 \({}^{\circ}\) & 519.00 \(\pm\) 10.61 \({}^{\circ}\) & 25.71 \(\pm\) 5.00 \({}^{\circ}\) & 0.30 \(\pm\) 0.04 \({}^{\circ}\) \\ N-NXDQ & MSH\_N & 12.27 \(\pm\) 0.52 \({}^{\circ}\) & 0.58 \(\pm\) 0.03 \({}^{\circ}\) & 2.26 \(\pm\) 0.01 \({}^{\circ}\) & 462.00 \(\pm\) 72.00 \({}^{\circ}\) & 22.56 \(\pm\) 4.54 \({}^{\circ}\) & 0.25 \(\pm\) 0.08 \({}^{\circ}\) \\  & MYP\_N & 13.33 \(\pm\) 0.88 \({}^{\circ}\) & 2.15 \(\pm\) 0.56 \({}^{\circ}\) & 2.65 \(\pm\) 0.07 \({}^{\circ}\) & 375.00 \(\pm\) 72.12 \({}^{\circ}\) & 33.64 \(\pm\) 0.31 \({}^{\circ}\) & 0.33 \(\pm\) 0.02 \({}^{\circ}\) \\ \hline \hline \end{tabular}
\end{table}
Table 1: Physicochemical properties of S-NXDQ and N-NXDQ.  
Figure 1: Cultivable microbial counts in S-NXDQ and N-NXDQ. (**a**) Cultivable aerobic bacterial counts. (**b**) Lactic acid bacterial counts. (**c**) Fungal counts. Letters above bars indicate significance markers, and different letters were significantly different (\(p<0.05\)).  
different between the two grades, while the fungal Shannon index of N-NXDQ was significantly higher than that of S-NXDQ. The results indicated that the N-NXDQ _daqu_ had a richer and more diverse fungal community, while the bacterial community in S-NXDQ was richer. The PCoA showed that there was a significant separation between S- and N-NXDQ (Figure 2c), indicating that the microbial structure in the two grades of NXDQ had different characteristics.  
Figure 2: \(\alpha\)-diversity and \(\beta\)-diversity analysis of the microbial community in two grades of NXDQ. (a) \(\alpha\)-diversity indexes for bacterial community. (b) \(\alpha\)-diversity indexes for fungal community. (c) PCoA analysis for bacterial community. (d) PCoA analysis for fungal community.