Lipid and Citric Acid Production by Wild Yeasts Grown in Glycerol

Abstract

In this study, crude glycerol was used as a carbon source in the cultivation of wild yeasts, aiming for the production of microbial lipids and citric acid. Forty yeasts of different sources were tested concerning their growth in crude and commercial glycerol. Four yeasts (Lidnera saturnus UFLA CES-Y677, Yarrowia lipolytica UFLA CM-Y9.4, Rhodotorula glutinis NCYC 2439, and Cryptococcus curvatus NCYC 476) were then selected owing to their ability to grow in pure (OD600 2.133, 1.633, 2.055, and 2.049, respectively) and crude (OD600 2.354, 1.753, 2.316, and 2.281, respectively) glycerol (10%, 20%, and 30%). Y. lipolytica UFLA CM-Y9.4 was selected for its ability to maintain cell viability in concentrations of 30% of crude glycerol, and high glycerol intake (18.907 g/l). This yeast was submitted to lipid production in 30 g/l of crude glycerol, and therefore obtained 63.4% of microbial lipids. In the fatty acid profile, there was a predominance of stearic (C18:0) and palmitic (C16:0) acids in the concentrations of 87.64% and 74.67%, respectively. We also performed optimization of the parameters for the production of citric acid, which yielded a production of 0.19 g/l of citric acid in optimum conditions (38.4 g/l of crude glycerol, agitation of 184 rpm, and temperature of 30°C). Yarrowia lipolytica UFLA CM-Y9.4 presented good lipid production when in the concentration of 30 g/l of glycerol. These data may be used for production in large quantities for the application of industrial biodiesel.

Overview of citric acid production from Aspergillus niger

“…Other factors that have effects on citric acid production include lipids, such as groundnut oil (Millis et al 1963;Kumar & Ethiraj 1976;Souza et al 2014), and sodium monofluoroacetate (Meixner-Monori et al 1984). Millis et al (1963) showed that lipid will improve the yield of citric acid with no effect of the dry weight of mycelium.…”

Bioprospecção de leveduras oleaginosas do Agreste Pernambucano: síntese de lipídios para a produção de biodiesel a partir do resíduo glicerol bruto

“…Neste sentido, o glicerol bruto vem sendo estudado como fonte de carbono para o crescimento de biomassa microbiana, produção de biodiesel e outros compostos como o ácido cítrico (Souza et al, 2014;Yen et al, 2015). Porém, o glicerol bruto apresenta possíveis inibidores do crescimento, como traças dos reagentes e do catalisador do processo de biodiesel (metanol e KOH), o que tem produzido inconvenientes, com rendimentos menores de crescimento celular, comparado ao glicerol purificado (Silva, Mack & Contiero, 2009).…”

“…A raiz deste, vários estudos foram desenvolvidos diante da possibilidade de usar o glicerol bruto como fonte de carbono de leveduras oleaginosas (leveduras com mais de 20% de lipídios na massa seca) para crescimento de biomassa microbiana (Raimondi et al, 2014;Yen et al, 2015) e produção de ácido cítrico e lipídios (Souza et al, 2014;Yen et al, 2015).…”

“…Yarrowia lipolytica pode acumular lipídios, até 40% do peso seco de células, e ácido linoleico em mais de 50% do total de ácidos graxos (Ratledge & Wynn, 2002). Os estudos mostram o potencial biotecnológico desta espécie quanto à produção de enzimas, ácido cítrico e consumo de oleatos, alcanos, ácidos graxos e glicerol bruto (Silva et al, 2010;Belo, 2013;Souza et al, 2014, Sara et al, 2016.…”

An Effective Method of Continuous Production of Erythritol from Glycerol by Yarrowia lipolytica MK1

“…The main fatt y acid in the yeast biomass was oleic acid (C18:1n9; 38.2 %), as observed when using other oleaginous yeasts (31,32). Oleic acid was described as the main monounsaturated fatt y (36). In turn, using industrial fats in the process with yeast resulted in a different total fatt y acid composition, which was characterised by a high concentration of cellular stearic acid (37).…”