黄水加碳酸钙粉末培养过程中理化性质和菌群组成的变化规律

Variations in the Physicochemical Properties and Bacterial Community Compositions during Culture of Yellow Water with Addition of Calcium Carbonate Powder

摘要:

该研究分析了浓香型新、老窖池黄水分别加入适量和过量碳酸钙粉末后，2个月静置培养过程中理化性质与菌群组成的变化规律。加适量与过量碳酸钙的新、老窖池黄水经过2个月培养，pH值（4.20~4.60→5.00~5.30，5.00~5.30→4.00~4.50）、丁酸和己酸先增后降，且pH值在加适量碳酸钙黄水中降低更显著；淀粉和还原糖呈持续降低；Ca2+浓度（4.82~6.32 g/L→5.53~8.89 g/L）、铵态氮（1.28~1.69 g/L→1.53~2.18 g/L）和乙酸（4.74~5.44 g/L→5.74~9.61 g/L）呈增加趋势，且Ca2+浓度在加过量碳酸钙黄水中增加更显著，铵态氮和乙酸在老窖池黄水中增加更显著；乳酸先降（62.21~64.57 g/L→54.67~57.74 g/L）后增（54.67~57.74 g/L→67.89~75.30 g/L），且在加适量碳酸钙黄水中增加更显著。在2个月的静置培养过程中，所有黄水样本的菌群多样性参数OTUs（125~169→83~90）、Chao1（133.08~174.44→88.08~95.52）和Shannon（1.43~2.24→0.57~0.83）均持续降低；绝对优势菌属Lactobacillus的相对丰度持续增加（94.48%→99.99%），但其它优势菌属及未知菌属趋于消亡（5.52%降至接近于0）。表明加入碳酸钙后黄水的理化环境更加有利于Lactobacillus占优势，而抑制了其它菌属的生长。本研究为退化窖泥中Lactobacillus占优势的现象提供了部分理论依据。

Abstract:

The bacterial community compositions and physicochemical properties of yellow water from young and old fermentation pits of strongly flavored liquors during two-month static culture after adding appropriate and excess amounts of calcium carbonate powder were invistigated. During the two-month culture, the pH value (from 4.20 to 4.60 → 5.00 to 5.30 for yellow water from the young pit; from 5.00 to 5.30 → 4.00 to 4.50 for that form the old pit) and the butyric and caproic acid contents increased and then decreased. Furthermore, the pH value dropped more significantly for yellow water with the addition of an appropriate amount of calcium carbonate powder. The starch and reducing sugar contents declined continuously. The calcium ion contents (from 4.82 to 6.32 g/L → 5.53 to 8.89 g/L), ammonium nitrogen (from 1.28 to 1.69 g/L → 1.53 to 2.18 g/L), and acetic acid (from 4.74 to 5.44 g/L → 5.74 to 9.61 g/L) increased. Moreover, the calcium ion concentration increased more remarkably for yellow water with excessive calcium carbonate, whereas the increases in the ammonium nitrogen and acetic acid contents were more considerable for yellow water from the old pit. The lactic acid content reduced first (from 62.21 to 64.57 g/L → 54.67 to 57.74 g/L) but then increased (from 54.67 to 57.74 g/L → 67.89 to 75.30 g/L); its increase is more noticeable for yellow water with an appropriate amount of calcium carbonate powder. The bacterial community diversity indices, including operational taxonomic units (from 125 to 169 → 83 to 90), Chao1 (from 133.08 to 174.44 → 88.08 to 95.52), and Shannon (from 1.43 to 2.24 → 0.57 to 0.83), decreased continuously during two-month culture for all yellow water samples. Meanwhile, the abundance of the predominant genus Lactobacillus grew continuously (from 94.48% → 99.99%), but the bacteria of other dominant and unknown genera died out gradually (from 5.52% to almost 0). The results demonstrate the environment is modified when calcium carbonate is added to yellow water, becoming more favorable for Lactobacillus. As a result, Lactobacillus becomes more dominant, while the growth of bacteria of other genera is inhibited. The findings of this study provide some theoretical explanation for the dominance of Lactobacillus in the mud of aging pits.