Abstract
Background
Few studies to date have sought to characterize the spatial profiles of pit mud microbial communities in fermentation cellars from Chinese strong-flavour liquor distilleries. This study was thus designed to evaluate these eukaryotic communities in pit mud samples via a multidimensional DGGE approach and by assessing associated sample physicochemical properties.
Results
Penicillium fuscoglaucum, Penicillium glandicola, Aotearoamyces nothofagi, Malassezia restricta, Penicillium lanosocoeruleum, Penicillium crustosum, and Aspergillus tonophilus were detected only in pit mud from the upper cellar wall, while Alternaria alstroemeriae, Trichosporon insectorum, Fusarium equiseti, Calonectria pseudoreteaudii, Penicillium clavigerum, Penicillium compactum, Ascochyta phacae, Metarhizium frigidum, Alternaria burnsii, Fusarium nurragi, and Didymella keratinophila were present only in the middle cellar wall layer. Alternaria zantedeschiae and Ilyonectria cyclaminicola were only present in pit mud samples from the lower cellar wall, while Leptobacillium leptobactrum, Calonectria queenslandica, Aspergillus appendiculatus, and Candida pseudolambica were only detected in pit mud from the cellar bottom. Moisture, pH, PO43−, acetic acid, humus, K+, Mg2+, Ca2+, acetic acid, butyric acid, and caproic acid levels in these different pit mud positions exhibited a rising incremental pattern from the upper wall layer to the bottom layer, whereas lactic acid levels were significantly lower in the bottom pit mud layer relative to other layers.
Conclusions
A clear relationship between fungal community structure and physicochemical variables in different spatial pit mud samples, especially moisture, pH, and NH4+-N were identified as the three most significant factors associated with fungal community through a redundancy analysis.
Preliminary Study on Caproic Acid Production by Compound Bacterial Agent of Luzhou-Flavor Liquor Pit Mud