## 3 Results and Discussion
### Fermentation Diversity and Dynamics  
A total of 65.581 bacterial and 37.917 fungi high-quality reads were obtained from the fermentation of coffee beans in the subtropical zone over 24 h. The OTU reads were distributed among 29 bacterial families and 43 fungal families (Figure 3). The Enterobacteriaceaeaceae and Erwiniaceae families were the predominant bacterial groups throughout the fermentation. Given that coffee pulp is rich in citrate, pectin, and other complex carbohydrates, bacteria from these families are likely involved in citrate fermentation during the initial stages of the coffee bean fermentation [20], as well as in pectin degradation and extracellular cellulase and protease activities throughout the process [21]. Although this microbial profile is uncommon in coffee fermentations, high-throughput sequencing analyses have shown these bacterial families to be predominant groups in Brazil and Australia [13; 17]. Nevertheless, the specific trends for individual families, such as Enterobacteriaceaeae and Methylobacteriaceae, are somewhat distinct from previous studies, possibly influenced by local conditions or specific fermentation practices. Moreover, other bacterial families such as Methylobacteriaceae, Sphingomonadaceae, and Pseudomonasaceae were present in large populations at the start of the process but experienced a significant decrease throughout fermentation. This trend could be attributed to environmental changes during the fermentation, including shifts in pH, temperature, or resource competition [22; 23; 24]. The fungal communities during fermentation were predominantly dominated by Nectiraceae, Cladosporiaceae, and, to a lesser extent, Aspergillus. The fluctuations and  
Figure 3: Relative abundance (%) of all microbial taxa at family and genus level identified during coffee fermentation in the subtropical zone. observed changes in these families suggest they possess specific roles or niches within the fermentation ecosystem. Their varying patterns and eventual stabilization or increase might be linked to the evolving conditions during fermentation. This microbial structure, composed mainly of filamentous fungi and enterobacteria, has been observed in coffee fermentations in Central America, South America, and Oceania regions [13; 14; 17; 22; 25; 26]. However, the role of these microorganisms in fermentation and the mechanisms of interaction are still poorly understood. At the genus level, the high diversity of bacteria and fungi at the beginning of the coffee fermentation is evident (Figure 3). This initial diversity likely reflects environmental microbial populations that are not specifically adapted to the coffee fermentation environment. As fermentation progresses, conditions such as pH, temperature, and nutrient availability change, favoring organisms that are more suited to the evolving environment of the coffee pulp [4]. _Pantoea_ showed an interesting pattern, starting with 25.25% at the beginning of the fermentation and peaking at 56.42% after 12 h, then gradually decreasing to 44.74% by the end. The initial surge and subsequent decline of _Pantoea_ suggest its significant but shifting role in coffee fermentation, potentially influencing the early flavor development stages. _Enterobacter_ showed a consistent increase from 12.28% at 0 h to 29.99% at 24 h. Other genera of bacteria present in high populations at the start of the fermentation, including _Methylobacterium_ (16.35%), _Pseudomonas_ (7.45%), and _Sphingomonas_ (5.52%), decreased dramatically to minimal levels at 24 h of fermentation. This indicates that these environment-related species are not adapted to coffee fermentation conditions, including nutrient availability and utilization, changes in pH and oxygen levels, competition and succession, and accumulation of metabolic by-products. The increasing trend of _Enterobacter_ could be associated with its role in later stages of fermentation, possibly affecting the final flavor profile of the coffee.