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Kim, Hee Sik; Jeon, Jong Woon; Lee, Hong Won; Park, Yong Il; Seo, Weon Taek; Oh, Hee‐Mock; Katsuragi, Tohoru; Tani, Yoshiki; Yoon, Byung Dae

doi:10.1023/a:1014100422857

Cited by 35 publications

(4 citation statements)

References 14 publications

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“…at 48 h (EI 24 greater than 60%) in the planktonic culture ( Figure 2 a). In most cases, the bacteria produced BE compounds at different times (h); in contrast, most studies state that the BE compounds are produced at the end of the exponential phase or the beginning of the stationary [ 57 , 58 , 59 ].…”

Section: Resultsmentioning

confidence: 99%

Bacteria Halotolerant from Karst Sinkholes as a Source of Biosurfactants and Bioemulsifiers

et al. 2022

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Halotolerant bacteria with biosurfactant (BS) and bioemulsifiers (BE) activity can coexist in Karstic sinkholes with marine influence. Two sinkholes in the Yucatan peninsula were selected to isolate bacteria with BE and BS activity stable in NaCl. The optimal time, the effect of nitrogen and carbon source in the medium, and the conditions (agitation, pH and salinity) for the production of BS and BE compounds in planktonic and sessile (stimulate the formation of biofilms in cell roller) culture were determined. Eighty strains showed the highest emulsification activity (EI24 ≥ 50%) and drop-collapse ≥ 4 mm. 87% of the strains are moderately halotolerant, and 21% bordered the limit of extreme halotolerance. Twenty-four strains maintained or improved their BS and BE activity under salinity conditions at 5% and 10%, being the most active genera Bacillus, Paenibacillus and Lysinibacillus, identified by sequencing of the 16S rRNA gene. The results show that the nitrogen source positively affects the BS and BE activity, regardless of the type of culture. The sessile culture markedly stimulated BS activity with significant differences. However, we did not find a greater influence on the culture conditions. The results suggest that halotolerant bacteria from sinkholes could be implemented in bioremediation and other biotechnological applications.

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Section: Resultsmentioning

confidence: 99%

Bacteria Halotolerant from Karst Sinkholes as a Source of Biosurfactants and Bioemulsifiers

et al. 2022

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“…217 As secondary metabolites, MELs are secreted largely by resting cells, 218 or under nitrogen limiting conditions. 219 Vegetable oils result in a better yield than glucose 220 when used alone 221 or in tandem with glucose as carbon sources. 219,222 Similar to rhamnolipid and sophorolipid production, higher yields are achieved in fed-batch bioreactors.…”

Section: Biosurfactantsmentioning

confidence: 99%

Derivation and synthesis of renewable surfactants

et al. 2012

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This critical review focuses on the origins and preparation of bio-based surfactants, defined here as non-soap, amphiphilic molecules in which the carbon atoms are derived from annually renewable feedstocks. Environmental concerns and market pressures have led to greater relevance of these chemicals in commercial applications in recent years and extensive research has gone into exploring new classes of surfactants. Highlighted here are examples of bio-based surfactants that are produced on an industrial scale and/or are based on abundant starting materials. The trend of increasing use of renewable resources as starting materials for surfactants is introduced, followed by extensive discussion of the major classes of bio-derived hydrophobes and hydrophiles. Also discussed is the status of research and development with regard to biosynthetically produced surfactants. Finally, concluding remarks address the potential for new surfactant molecular structures as a result of ongoing development in the chemistry of biorefineries, i.e., that the transformation of lignocellulose into fuels is likely to support the manufacturing of new bio-based coproducts (238 references).

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“…No parameter optimization was performed for this publication. Building on another study in which the process was optimized in shake flasks ( Kim et al, 2002 ), Kim et al (2006) later described a two-stage fed-batch fermentation using 30 g/L glucose and soybean oil (1:1 w/w) for growth and a subsequent feed of soybean oil (170 g/L in total) for MEL production. The fermentation in a 5-L bioreactor was conducted at a controlled dissolved oxygen level of 20% by varying stirrer speed (500–750 rpm) and aeration rate (0.two to two vvm) accordingly.…”

Section: Introductionmentioning

confidence: 99%

Optimization and Kinetic Modeling of a Fed-Batch Fermentation for Mannosylerythritol Lipids (MEL) Production With Moesziomyces aphidis

Beck

Vogt

Hägele

et al. 2022

Front. Bioeng. Biotechnol.

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Mannosylerythritol lipids are glycolipid biosurfactants with many interesting properties. Despite the general interest in those molecules and the need for a robust process, studies on their production in bioreactors are still scarce. In the current study, the fermentative production of MEL in a bioreactor with Moesziomyces aphidis was performed using a defined mineral salt medium. Several kinetic process parameters like substrate consumption rates and product formation rates were evaluated and subsequently enhanced by increasing the biomass concentration through an exponential fed-batch strategy. The fed-batch approaches resulted in two to three fold increased dry biomass concentrations of 10.9–15.5 g/L at the end of the growth phase, compared with 4.2 g/L in the batch process. Consequently, MEL formation rates were increased from 0.1 g/Lh up to around 0.4 g/Lh during the MEL production phase. Thus, a maximum concentration of up to 50.5 g/L MEL was obtained when oil was added in excess, but high concentrations of residual fatty acids were also present in the broth. By adjusting the oil feeding to biomass-specific hydrolysis and MEL production rates, a slightly lower MEL concentration of 34.3 g/L was obtained after 170 h, but at the same time a very pure crude lipid extract with more than 90% MEL and a much lower concentration of remaining fatty acids. With rapeseed oil as substrate, the ideal oil-to-biomass ratio for full substrate conversion was found to be around 10 goil/gbiomass. In addition, off-gas analysis and pH trends could be used to assess biomass growth and MEL production. Finally, kinetic models were developed and compared to the experimental data, allowing for a detailed prediction of the process behavior in future experiments.

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Cited by 35 publications

References 14 publications

Bacteria Halotolerant from Karst Sinkholes as a Source of Biosurfactants and Bioemulsifiers

Bacteria Halotolerant from Karst Sinkholes as a Source of Biosurfactants and Bioemulsifiers

Derivation and synthesis of renewable surfactants

Optimization and Kinetic Modeling of a Fed-Batch Fermentation for Mannosylerythritol Lipids (MEL) Production With Moesziomyces aphidis

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