A Thermotolerant Yeast Cyberlindnera rhodanensis DK Isolated from Laphet-so Capable of Extracellular Thermostable β-Glucosidase Production

Abstract

This study aims to utilize the microbial resources found within Laphet-so, a traditional fermented tea in Myanmar. A total of 18 isolates of thermotolerant yeasts were obtained from eight samples of Laphet-so collected from southern Shan state, Myanmar. All isolates demonstrated the tannin tolerance, and six isolates were resistant to 5% (w/v) tannin concentration. All 18 isolates were capable of carboxy-methyl cellulose (CMC) degrading, but only the isolate DK showed ethanol production at 45 °C noticed by gas formation. This ethanol producing yeast was identified to be Cyberlindnera rhodanensis based on the sequence analysis of the D1/D2 domain on rRNA gene. C. rhodanensis DK produced 1.70 ± 0.01 U of thermostable extracellular β-glucosidase when cultured at 37 °C for 24 h using 0.5% (w/v) CMC as a carbon source. The best two carbon sources for extracellular β-glucosidase production were found to be either xylose or xylan, with β-glucosidase activity of 3.07–3.08 U/mL when the yeast was cultivated in the yeast malt extract (YM) broth containing either 1% (w/v) xylose or xylan as a sole carbon source at 37 °C for 48 h. The optimal medium compositions for enzyme production predicted by Plackett–Burman design and central composite design (CCD) was composed of yeast extract 5.83 g/L, peptone 10.81 g/L and xylose 20.20 g/L, resulting in a production of 7.96 U/mL, while the medium composed (g/L) of yeast extract 5.79, peptone 13.68 and xylan 20.16 gave 9.45 ± 0.03 U/mL for 48 h cultivation at 37 °C. Crude β-glucosidase exhibited a remarkable stability of 100%, 88% and 75% stable for 3 h at 35, 45 and 55 °C, respectively.

Valorization of Cashew Apple Waste into a Low-Alcohol, Healthy Drink Using a Co-Culture of Cyberlindnera rhodanensis DK and Lactobacillus pentosus A14-6

“…The observed variations in enzyme activity between mono-fermentation and co-fermentation highlight the dynamic nature of microbial interactions during the fermentation process. In mono-fermentation, enzyme activity increased, indicating that C. rhodanensis DK had a positive impact on enzyme production [18]. This result aligns with the findings of Kodchasee et al [14], who studied C. rhodanensis isolated from miang and found its capability of β-glucosidase production during the fermentation process of low-alcoholic miang wine.…”

“…The yeast strain C. rhodanensis DK used in this research was isolated from a sample of laphet-so, a fermented tea collected from the southern Shan state of Myanmar [18]. Saccharomyces cerevisiae TISTR 5088, obtained from the culture collection of the Thailand Institute of Scientific and Technological Research (TISTR), and Lactobacillus pentosus A14-6, tannin-tolerant with probiotic properties originally isolated from samples of miang [21], were used in the study.…”

“…Kodchasee et al [14] reported that C. rhodanensis produces not only β-glucosidase enzyme but also enhances the formation of esters, ethyl acetate, isoamyl acetate, and essential esters in wine production. We hypothesized that C. rhodanensis DK derived from fermented tea products ('laphet') of Myanmar is a yeast strain capable of producing β-glucosidase and therefore facilitating aroma characteristics by releasing aromatic compounds through cleavage of glycoside bonds between aroma molecules and terminal sugar [18].…”

Tannin-Tolerant Saccharomyces cerevisiae Isolated from Traditional Fermented Tea Leaf (Miang) and Application in Fruit Wine Fermentation Using Longan Juice Mixed with Seed Extract as Substrate

“…The natural selection of microbial populations with tannin-tolerance capabilities is a fundamental mechanism in fermentation processes [8,31]. In another study, Kham et al [32] identified groups of yeast isolates from traditional fermented tea capable of growth within a range of 0.5% to 3%. Similarly, Kanpiengjai et al [7] reported that yeast isolates in Miang demonstrated tannin tolerance characteristics and the presence of tannase-degrading enzymes during Miang fermentation.…”