Three new yeast species from flowers of Camellia sinensis var. assamica collected in Northern Thailand and their tannin tolerance characterization

Abstract

Our recent research study focused on Miang fermentation revealed that tannin-tolerant yeasts and bacteria play vital roles in the Miang production process. A high proportion of yeast species are associated with plants, insects, or both, and nectar is one of the unexplored sources of yeast biodiversity. Therefore, this study aimed to isolate and identify yeasts of tea flowers of Camellia sinensis var. assamica and to investigate their tannin tolerance, which is a property essential to Miang production processes. A total of 82 yeasts were recovered from a total of 53 flower samples in Northern Thailand. It was found that two and eight yeast strains were distinct from all other known species within the genera Metschnikowia and Wickerhamiella, respectively. These yeast strains were described as three new species, namely, Metschnikowia lannaensis, Wickerhamiella camelliae, and W. thailandensis. The identification of these species was based on phenotypic (morphological, biochemical, and physiological characteristics) and phylogenetic analyses of a combination of the internal transcribed spacer (ITS) regions and the D1/D2 domains of the large subunit (LSU) ribosomal RNA gene. The yeast diversity in tea flowers acquired from Chiang Mai, Lampang, and Nan provinces had a positive correlation with those acquired from Phayao, Chiang Rai, and Phrae, respectively. Wickerhamiella azyma, Candida leandrae, and W. thailandensis were the species uniquely found in tea flowers collected from Nan and Phrae, Chiang Mai, and Lampang provinces, respectively. Some of the tannin-tolerant and/or tannase-producing yeasts were associated with yeasts in the commercial Miang process and those found during Miang production, i.e., C. tropicalis, Hyphopichia burtonii, Meyerozyma caribbica, Pichia manshurica, C. orthopsilosis, Cyberlindnera fabianii, Hanseniaspora uvarum, and Wickerhamomyces anomalus. In conclusion, these studies suggest that floral nectar could support the formation of yeast communities that are beneficial for Miang production.

Purification and characterization of crude fructooligosaccharides extracted from red onion (Allium cepa var. viviparum) by yeast treatment

“…( Camellia) sinensis var. assamica , as has been indicated in previous studies [ 17 , 18 ]. They were stored at −20 °C in yeast extract-malt extract broth (YMB) supplemented with 15% (v/v) glycerol.…”

“…All yeast species were isolated from Miang, the fermented tea leaves of northern ethnic people of Thailand, and the flowers of Assam tea collected near the Miang plantation areas. Current research has found that the diversity of the yeast species of Miang were associated with the yeast communities present in the flowers of the Assam tea [ 17 , 18 ]. Nectar consists of sucrose as the main sugar, followed by glucose and fructose, which are varied depending upon the flower type.…”

“…The main objective of this research study was to screen yeast strains isolated from Miang, traditionally fermented Assam tea leaves ( Camellia sinensis var. assamica ) of northern Thailand [ 17 ], and flowers of Assam tea [ 18 ], for selective removal of the unwanted sugars present in crude FOSs obtained from red onions. The reaction mechanisms associated with the purification of FOSs by the selected yeast strains have also been proposed.…”

Wickerhamiella lachancei f.a. sp. nov., a novel ascomycetous yeast species isolated from flowers of Lantana camara in India

“…Species within the Wickerhamiella clade have been documented in various ecological niches, with a predominant association with flowers, nectar, and floricolous insects [1,7,[29][30][31][32]. Numerous species of the genus Wickerhamiella, such as W. australiensis, W. occidentalis, W. drosophilae, W. lipophila, W. alocasiicola, W. musiphila, W. jalapaonensis, W. azyma, W. pagnoccae, W. kiyanii, W. fructicola, W. kurtzmanii, W. nakhonpathomensis, W. bidentis, and W. camelliae, have been isolated from flowers [6,7,33,34]. Similarly, W. lachancei sp.…”

“…Nectar yeasts often exhibit nutritional specialization and can be also found in flowers, floricolous insects, fruits, and plant leaves [2]. The exploration of yeast diversity from flowers and their interacting insect visitors has led to the discovery of over 50 new yeast species in the past decade, predominantly belonging to genera such as Metschnikowia, Wickerhamiella, Starmerella, and Kodamaea [1,[3][4][5][6][7].…”