Abstract:

The study aims to understand the microbial diversity during the natural fermentation of organic fertilizer from macadamia peels and to investigate the changes in microbial community structure at different fermentation stages. Using naturally fermented macadamia peels as test materials, 16S and ITS high-throughput sequencing technology and bioinformatics were used to analyze the diversity of bacteria and fungi as well as changes in community composition during 3 stages of the organic fertilizer, namely, the warming period (<45℃), the high-temperature period (>45℃) and the cooling period (<45℃). The self-fermentation of macadamia peels was able to rapidly warm up and maintain a high temperature period for 6 days, with the maximum temperature reaching 57.52℃. α-diversity analysis revealed that the abundance and diversity of microorganisms in the self-fermentation of peels increased gradually with fermentation, and the diversity of fungi was higher than that of bacteria; the structure of microbial community was in dynamic change with fermentation, and the dominant bacteria in each stage of fermentation were Ascomycetes, with the highest percentage of 88.58% at high-temperature period; the dominant fungi were Ascomycetes with 60.5% at cooling period of fermentation. This study elucidated the diversity of microorganisms and their community structure changes during the natural fermentation of organic fertilizer from macadamia peels, and laid a theoretical foundation for the subsequent screening and development of special fermentation bacterial agents for organic fertilizer from macadamia peels.

Key words: macadamia peels, fermentation, fermentation temperature, microbial diversity, microbial community structure