Effect of carbon sources on the growth and ethanol production of native yeast Pichia kudriavzevii ITV-S42 isolated from sweet sorghum juice

Abstract

The importance of non-Saccharomyces yeast species in fermentation processes is widely acknowledged. Within this group, Pichia kudriavzevii ITV-S42 yeast strain shows particularly desirable characteristics for ethanol production. Despite this fact, a thorough study of the metabolic and kinetic characteristics of this strain is currently unavailable. The aim of this work is to study the nutritional requirements of Pichia kudriavzevii ITV-S42 strain and the effect of different carbon sources on the growth and ethanol production. Results showed that glucose and fructose were both assimilated and fermented, achieving biomass and ethanol yields of 0.37 and 0.32 gg, respectively. Glycerol was assimilated but not fermented; achieving a biomass yield of 0.88 gg. Xylose and sucrose were not metabolized by the yeast strain. Finally, the use of a culture medium enriched with salts and yeast extract favored glucose consumption both for growth and ethanol production, improving ethanol tolerance reported for this genre (35 g L) to 90 g L maximum ethanol concentration (over 100%). Furthermore Pichia kudriavzevii ITV-S42 maintained its fermentative capacity up to 200 g L initial glucose, demonstrating that this yeast is osmotolerant.

The ability of Pichia kudriavzevii to tolerate multiple stresses makes it promising for developing improved bioethanol production processes

“…Recently, a number of reports have highlighted P. kudriavzevii as an effective thermotolerant yeast strain for the fermentation of bioethanol from sugarcane juice (Dhaliwal et al 2011), sweet sorghum juice (Techaparin et al 2017) and cassava pulp (Ndubuisi et al 2018). Our thermotolerance data were consistent with the previous literature, with other P. kudriavzevii strains being reported to grow at temperatures above 40°C (Sirisan et al 2013;Costa et al 2014;Choi et al 2017;D ıaz-Nava et al 2017). Moreover, the three NUNS isolates were also resistant to high ethanol and sodium chloride concentration.…”

Comprehending the influence of critical cultivation parameters on the oleaginous behaviour of potent rotten fruit yeast isolates

“…Among the identified yeasts P. kudriavzevii is a well‐recognized non‐ saccharomyces ethanol‐producing yeast, known for its hexose and pentose fermenting ability (Díaz‐Nava et al . ). The species has received considerable biotechnological importance due to its contribution in various fields, such as single‐cell protein (Rachamontree et al .…”

Produção de biopigmentos pela levedura >i<Pichia kudriavzevii>/i< cultivada em subprodutos agroindustriais

“…kudriavzevii, uma vez que essa levedura é particularmente tolerante a inibidores e há indícios de que seja capaz de metabolizar esses compostos (DÍAZ-NAVA et al, 2017;FONSECA, 2009;HOU-RUI et al, 2009). O estudo de Fonseca (2009), por exemplo, demonstrou que o cultivo de P. kudriavzevii em hidrolisado não destoxificado e concentrado de bagaço de canade-açúcar contendo 1,6•10 -2 g/L de furfural, 2•10 -2 g/L de 5-HMF, 0,6 g/L de siringaldeído e 0,3 g/L de ácido ferúlico reduziu a concentração desses inibidores em 100%, 85%, 16,7% e 16,7%, respectivamente.…”

“…A capacidade da levedura P. kudriavzevii de crescer em ambientes com alta salinidade e alta concentração de inibidores tem sido relatada em inúmeras publicações (DÍAZ-NAVA et al, 2017;HOU-RUI et al, 2009;RADECKA et al, 2015;ROȘU et al, 2019;XIAO et al, 2014). Em relação aos furfurais, destaca-se a publicação de Kwon et al (2011), a qual demonstrou que a concentração de furfural e de 5-HMF que inibiu completamente a levedura foi de 7 g/L.…”

“…Esses dados são indicativos da baixa atividade do metabolismo de pentoses dessa levedura e justificam a reduzida produção de biomassa verificada no presente trabalho (Figura 14b). Aponta-se, também, o fato de alguns autores relatarem a incapacidade de algumas linhagens de P. kudriavzevii de assimilar e metabolizar xilose (DÍAZ-NAVA et al, 2017;OBEROI et al, 2012).…”