A strain of Meyerozyma guilliermondii isolated from sugarcane juice is able to grow and ferment pentoses in synthetic and bagasse hydrolysate media

Abstract

The search for new microbial strains that are able to withstand inhibitors released from hemicellulosic hydrolysis and are also still able to convert sugars in ethanol/xylitol is highly desirable. A yeast strain isolated from sugarcane juice and identified as Meyerozyma guilliermondii was evaluated for the ability to grow and ferment pentoses in synthetic media and in sugarcane bagasse hydrolysate. The yeast grew in xylose, arabinose and glucose at the same rate at an initial medium pH of 5.5. At pH 4.5, the yeast grew more slowly in arabinose. There was no sugar exhaustion within 60 h. At higher xylose concentrations with a higher initial cell concentration, sugar was exhausted within 96 h at pH 4.5. An increase of 350 % in biomass was obtained in detoxified hydrolysates, whereas supplementation with 3 g/L yeast extract increased biomass production by approximately 40 %. Ethanol and xylitol were produced more significantly in supplemented hydrolysates regardless of detoxification. Xylose consumption was enhanced in supplemented hydrolysates and arabinose was consumed only when xylose and glucose were no longer available. Supplementation had a greater impact on ethanol yield and productivity than detoxification; however, the product yields obtained in the present study are still much lower when compared to other yeast species in bagasse hydrolysate. By the other hand, the fermentation of both xylose and arabinose and capability of withstanding inhibitors are important characteristics of the strain assayed.

Ethanol production from Dekkera bruxellensis in synthetic media with pentose

“…In this way, a viable production of ethanol from biomass implicates the use of microorganisms that are able to ferment not only glucose but all sugars present in the lignocellulosic hydrolysates, such as D-xylose, L-arabinose, D-cellobiose, D-galactose and D-mannose with high yield and productivity (van Maris et al, 2006;Hahn-Hägerdal et al, 2007;Bettiga et al, 2008;Fukuda et al, 2009;Martini et al, 2016).…”

Oleaginous yeast Meyerozyma guilliermondii shows fermentative metabolism of sugars in the biosynthesis of ethanol and converts raw glycerol and cheese whey permeate into polyunsaturated fatty acids

“…There are few data on ethanol production by this yeast strain. Cultures of M. guilliermondii CCT7783 using xylose or sugarcane bagasse hydrolysate as substrates produced negligible amounts of ethanol (Y p/s 0.04 at 120 hr in xylose and 0.14 at 144 hr in the hydrolysate, respectively) . This same strain growing in semi‐synthetic media containing a mixture of glucose, arabinose, xylose, and furfural, produced ethanol at yields of (Y p/s ) 0.33 in 96 hr .…”

Identification of genes involved in xylose metabolism of Meyerozyma guilliermondii and their genetic engineering for increased xylitol production

“…It would be interesting to see whether expression of heterologous XRs, improving xylose uptake or co-factor balancing could enhance this strains productivity. Meyerozyma guilliermondii is a promising potential candidate that can grow on alternative substrates as carbon sources in biotechnological production processes (Carvalho et al 2002;Mussatto et al 2006;Pereira et al 2011;Cassabarbosa et al 2015;Hernández-Pérez et al 2016;Martini et al 2016;López-Linares et al 2018). Insight into the genetic mechanisms underlying its xylose metabolism and its growth behavior will facilitate its future use as cell factory.…”