Bacterial and fungal communities of long-term fermented medicinal plant extracts
Microbial fermentation is a traditional method applied worldwide to produce a variety of goods, e.g. food, beverages, forage crops and industrial chemicals. It provides an inexhaustible source of bioactive compounds with promising properties for human well-being, nutrition, diet quality and pharmaceutical applications. So far, little attention has been paid to the fermented medicinal plants (FMPs), with their high metabolic potential of microbial transformations to enhance the formation of health-promoting compounds.  To shed more light on this largely unexplored field we analysed the composition of bacterial and fungal communities of 16 FMPs after long-term fermentation of more than six months. The FMPs comprised Achillea millefolium, Aesculus hippocastanum, Allium cepa, Arnica montana, Berberis vulgaris, Calendula officinalis, Echinacea pallida, Euphrasia officinalis, Geum urbanum, Mercurialis perennis, Origanum major, Plantago lanceolata, Salvia officinalis, Silybum marianum, Symphytum officinale and Taraxacum officinale. Fermentation was conducted according to a standardized pharmaceutical method. Bacterial and fungal diversities were assessed and frequent FMP-specific lineages of both microbial groups were identified. Lactic acid bacteria and yeasts were the predominant taxa in most FMPs, whereas in a few FMPs also Bacillales and Enterobacterales constituted prominent proportions. A hierarchical cluster analysis of the microbial communities revealed eight bacterial and seven fungal clusters. Several FMPs harbored communities assigned to one or two specific clusters, whereas in other FMPs communities assigned to more clusters were present.  The FMPs exhibited specific bacterial and fungal core communities with several key members. This comprehensive study greatly enlarges our knowledge on the value and diversity of bacterial and fungal communities in fermented medicinal plant extracts.
Microbial fermentation is a traditional method applied worldwide to produce a variety of goods, e.g. food, beverages, forage crops and industrial chemicals. It provides an inexhaustible source of bioactive compounds with promising properties for human well-being, nutrition, diet quality and pharmaceutical applications. So far, little attention has been paid to the fermented medicinal plants (FMPs), with their high metabolic potential of microbial transformations to enhance the formation of health-promoting compounds.  To shed more light on this largely unexplored field we analysed the composition of bacterial and fungal communities of 16 FMPs after long-term fermentation of more than six months. The FMPs comprised Achillea millefolium, Aesculus hippocastanum, Allium cepa, Arnica montana, Berberis vulgaris, Calendula officinalis, Echinacea pallida, Euphrasia officinalis, Geum urbanum, Mercurialis perennis, Origanum major, Plantago lanceolata, Salvia officinalis, Silybum marianum, Symphytum officinale and Taraxacum officinale. Fermentation was conducted according to a standardized pharmaceutical method. Bacterial and fungal diversities were assessed and frequent FMP-specific lineages of both microbial groups were identified. Lactic acid bacteria and yeasts were the predominant taxa in most FMPs, whereas in a few FMPs also Bacillales and Enterobacterales constituted prominent proportions. A hierarchical cluster analysis of the microbial communities revealed eight bacterial and seven fungal clusters. Several FMPs harbored communities assigned to one or two specific clusters, whereas in other FMPs communities assigned to more clusters were present.  The FMPs exhibited specific bacterial and fungal core communities with several key members. This comprehensive study greatly enlarges our knowledge on the value and diversity of bacterial and fungal communities in fermented medicinal plant extracts.
WALA Heilmittel GmbH