Isolation and Identification of Yeast Strains From Sugarcane Molasses, Dates and Figs for Ethanol Production Under Conditions Simulating Algal Hydrolysate

Abstract

Yeast strains were isolated from sugar cane molasses (S1), dates (S2) and figs (S3) and the ethanol production was evaluated in batch condition. A comparison was made with the yeast Saccharomyces cerevisiae. The strains showed tolerant characteristics to stressful conditions like salinity and ethanol. The isolated strains produced ethanol; at 20 h of fermentation ethanol yields were 0.38-0.39 g.g-1 , and the productivities were almost 0.58 g.L-1. S. cerevisiae and S1 tolerated up to 14% (v/v) of ethanol; while interestingly the isolates S2 and S3 were highly tolerant, up to 20% (v/v) ethanol. Thus, S2 and S3 could serve as potential strains for ethanol fermentation, with 0.27 and 0.29 g.g-1 yield of ethanol in the presence of 1.37 mol.L-1 NaCl. These values were higher than the value obtained using the yeast of reference and S1 (0.16 g.g-1). Co-cultures of S2 and S3 enhanced the ethanol production, increasing the yield of ethanol by 12.5% compared with the single culture. The strains were identified as species S.cerevisiae, and S2 and S3 were very similar. For an application in the valorization of biomass such as green macro-algae, some assays were done on a synthetic model medium of hydrolysate of macro-algae and the strains S2 and S3 demonstrated excellent fermentative performances.

Molecular characterization and bioactive potential of newly identified strains of the extremophilic black yeastHortaea werneckiiisolated from Red Sea mangrove

“…Despite being grown on the same media and under the same conditions, these strains showed distinct culture features (Figure 1) but revealed similar microscopic characteristics (Figure 2). Similar observations have been witnessed in Saccharomyces cerevisiae, in which different strains isolated from different plant sources, including dates, sugarcane and figs, possessed the same microscopic features and needed further genetic identification via PCR based markers to differentiate between them [34].…”

The Utilization of Vegetable and Fruit Wastes for Saccharomyces cerevisieae Cell Wall Based β-Glucan Production with Antioxidant Activity

“…The main nutrients in the form of carbohydrates that are often found in the form of sugar are important nutrients in the S.cerevisiae fermentation process. Sugar is one of the main component that act as energy producers which found in the form of glucose, sucrose, maltose, cellulose, hemicellulose, lactose, and fructose (Kechkar et al, 2019). The sugar component other than glucose will firstly be converted to glucose in the presence of enzyme, such as invertase and zimase, from S. cerevisiae (Ostergaard et al, 2000).…”

Never Change a Brewing Yeast? Why Not, There Are Plenty to Choose From

“…Particularly, in Brazilian bioethanol plants, the specific operating conditions allow for the entry and growth of wild yeast strains (Amorim et al, 2011). The initial yeast starter cultures were replaced over time by indigenous strains present in sugar cane molasses that would outperform the domesticated yeasts due to their resistance to high ethanol levels and temperature fluctuations (Beato et al, 2016;Reis et al, 2017;Kechkar et al, 2019). Recently, several S. cerevisiae strains isolated from Brazilian distilleries have been investigated in high gravity beer fermentations (Christofoleti-Furlan et al, 2020), clearly showing they harbor a potential for use in the brewing industry.…”