The microbial ecology in the fermentation of Australian coffee beans was investigated in this study. Pulped coffee beans were kept underwater for 36 h before air dried. Samples were collected periodically, and the microbial communities were analyzed by culture-dependent and independent methods. Changes in sugars, organic acids and microbial metabolites in the mucilage and endosperm of the coffee beans during fermentation were monitored by HPLC. Culture-dependent methods identified 6 yeast and 17 bacterial species, while the culture-independent methods, multiple-step total direct DNA extraction and high throughput sequencing, identified 212 fungal and 40 bacterial species. Most of the microbial species in the community have been reported for wet fermentation of coffee beans in other parts of the world, but the yeast Pichia kudriavzevii was isolated for the first time in wet coffee bean fermentation. The bacterial community was dominated by aerobic mesophilic bacteria (AMB) with Citrobacter being the predominant genus. Hanseniaspora uvarum and Pichia kudriavzevii were the predominant yeasts while Leuconostoc mesenteroides and Lactococcus lactis were the predominant LAB. The yeasts and bacteria grew significantly during fermentation, utilizing sugars in the mucilage and produced mannitol, glycerol, and lactic acid, leading to a significant decrease in pH. The results of this study provided a preliminary understanding of the microbial ecology of wet coffee fermentation under Australian conditions. Further studies are needed to explore the impact of microbial growth and metabolism on coffee quality, especially flavour.

这项研究调查了澳大利亚咖啡豆发酵过程中的微生物生态。制粒的咖啡豆在风干之前​​会在水下放置36小时。定期收集样品，并通过依赖于培养的方法和独立的方法分析微生物群落。通过HPLC监测咖啡豆在发酵过程中的粘液和胚乳中糖，有机酸和微生物代谢产物的变化。依赖培养物的方法可鉴定出6种酵母和17种细菌，而依赖培养物的方法，多步骤总直接DNA提取和高通量测序可鉴定出212种真菌和40种细菌。在世界其他地区，据报道该社区中大多数微生物都用于咖啡豆的湿发酵，但是酵母在湿咖啡豆发酵中首次分离出库德毕赤酵母。细菌群落主要由好氧嗜温菌（AMB）主导，其中柠檬酸杆菌为主要属。Hanseniaspora uvarum和毕赤酵母（Pichia kudriavzevii）是主要的酵母菌，而肠膜明串珠菌和乳酸乳球菌是主要的LAB。酵母和细菌在发酵过程中大量生长，利用粘液中的糖分产生了甘露醇，甘油和乳酸，导致pH值明显降低。这项研究的结果提供了对澳大利亚条件下湿咖啡发酵微生物生态学的初步了解。需要进一步的研究，以探讨微生物生长和代谢对咖啡品质（尤其是风味）的影响。