Dynamics of ethanol production from whey and whey permeate by immobilized strains of Kluyveromyces marxianus in batch and continuous bioreactors

Gabardo, Sabrina; Rech, Rosane; Rosa, Carlos A.; Ayub, Marco Antônio Záchia

doi:10.1016/j.renene.2014.03.023

Cited by 43 publications

(36 citation statements)

References 40 publications

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“…Another strategy for improving ethanol yield is the use of cell immobilization, which allows protecting cells from inhibitory products and environmental variations, resulting in smaller bioreactor volumes and lower costs. In this respect, Gabardo et al (2014) showed that immobilized cells of K. marxianus in Ca-alginate improved ethanol yield in continuous culture fermentations. The maximum value achieved was found for K. marxianus CCT 4086 with a productivity of 6.97 g/ L/h; this being one of the highest values reported to date.…”

Section: Biofuelsmentioning

confidence: 99%

Whey-derived valuable products obtained by microbial fermentation

Pescuma

Valdez

Mozzi

2015

Appl Microbiol Biotechnol

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Whey, the main by-product of the cheese industry, is considered as an important pollutant due to its high chemical and biological oxygen demand. Whey, often considered as waste, has high nutritional value and can be used to obtain value-added products, although some of them need expensive enzymatic synthesis. An economical alternative to transform whey into valuable products is through bacterial or yeast fermentations and by accumulation during algae growth. Fermentative processes can be applied either to produce individual compounds or to formulate new foods and beverages. In the first case, a considerable amount of research has been directed to obtain biofuels able to replace those derived from petrol. In addition, the possibility of replacing petrol-derived plastics by biodegradable polymers synthesized during bacterial fermentation of whey has been sought. Further, the ability of different organisms to produce metabolites commonly used in the food and pharmaceutical industries (i.e., lactic acid, lactobionic acid, polysaccharides, etc.) using whey as growth substrate has been studied. On the other hand, new low-cost functional whey-based foods and beverages leveraging the high nutritional quality of whey have been formulated, highlighting the health-promoting effects of fermented whey-derived products. This review aims to gather the multiple uses of whey as sustainable raw material for the production of individual compounds, foods, and beverages by microbial fermentation. This is the first work to give an overview on the microbial transformation of whey as raw material into a large repertoire of industrially relevant foods and products.

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Section: Biofuelsmentioning

confidence: 99%

Whey-derived valuable products obtained by microbial fermentation

Pescuma

Valdez

Mozzi

2015

Appl Microbiol Biotechnol

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“…However, standard yeast has high mortality when ethanol concentration of 10% v/v is reached 22 . Alcoholic beverages with higher content of ethanol are prepared by distillation and some biotechnological processes are also proposed to have higher efficacy in ethanol production 23,24 e.g. whisky has around 40% v/v (ref.…”

Section: Production and Use Of The Alcoholsmentioning

confidence: 99%

Toxicology and the biological role of methanol and ethanol: Current view

Pohanka¹

2016

Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub

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Background. Alcohol variants such as ethanol and methanol are simple organic compounds widely used in foods, pharmaceuticals, chemical synthesis, etc. Both are becoming an emerging health problem; abuse of ethanol containing beverages can lead to disparate health problems and methanol is highly toxic and unfit for consumption. Methods and Results. This review summarizes the basic knowledge about ethanol and methanol toxicity, the effect mechanism on the body, the current care of poisoned individuals and the implication of alcohols in the development of diseases. Alcohol related dementia, stroke, metabolic syndrome and hepatitis are discussed as well. Besides ethanol, methanol toxicity and its biodegradation pathways are addressed. Conclusions. The impact of ethanol and methanol on the body is shown as case reports, along with a discussion on the possible implication of alcohol in Alzheimer's disease and antidotal therapy for methanol poisoning. The role of ethanol in cancer and degenerative disorders seems to be underestimated given the current knowledge. Treatment in case of poisoning is another issue that remains unresolved even though effective protocols and drugs exist.

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“…This strain was chosen because it has shown a high capacity for lactose bioconversion into ethanol as it has been observed in our recent publications [13,14]. For cell maintenance, the strain was kept frozen at −20 °C in a 60 % cell suspension in glycerol, whereas for immediate use cells were kept on YEP-Lactose agar slants at 4 °C [11].…”

Section: Yeasts Cell Maintenance and Materialsmentioning

confidence: 99%

“…Ethanol can be obtained by fermentation of different raw materials, such as agro-industrial residues, and using several microorganisms [7,14,21,32,53]. Whey, which is a by-product (sometimes a waste material) of dairy industries, is an abundant and inexpensive substrate, rich in nutrients, which could be used for ethanol fermentation because of its unique composition: high lactose content (45-50 g L −1 ), protein (6-8 g L −1 ), lipids (4-5 g L −1 ), and mineral salts (5-7 g L −1 ) [14,17,23,38,46]. Different technologies have been studied to improve the ethanol fermentation process.…”

Section: Introductionmentioning

confidence: 99%

“…Several approaches for ethanol production in continuous cell-immobilized bioreactors have been investigated using different support materials and substrates [25,27,33,35,49,54], but only recently researchers have reported the use of whey for ethanol production in immobilized continuous systems [6,13,14,38]. Considering the ever-increasing demand for ethanol production, various mathematical models have been attempted in order to predict the effect of fermentation variables on cell growth, substrate utilization rate, and ethanol production rate [4,15,43], thus allowing for better processes design.…”

Section: Introductionmentioning

confidence: 99%

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The modeling of ethanol production by Kluyveromyces marxianus using whey as substrate in continuous A-Stat bioreactors

Gabardo

Pereira

Rech

et al. 2015

Journal of Industrial Microbiology and Biotechnology

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We investigated the kinetics of whey bioconversion into ethanol by Kluyveromyces marxianus in continuous bioreactors using the "accelerostat technique" (A-stat). Cultivations using free and Ca-alginate immobilized cells were evaluated using two different acceleration rates (a). The kinetic profiles of these systems were modeled using four different unstructured models, differing in the expressions for the specific growth (μ) and substrate consumption rates (r s), taking into account substrate limitation and product inhibition. Experimental data showed that the dilution rate (D) directly affected cell physiology and metabolism. The specific growth rate followed the dilution rate (μ≈D) for the lowest acceleration rate (a = 0.0015 h(-2)), condition in which the highest ethanol yield (0.52 g g(-1)) was obtained. The highest acceleration rate (a = 0.00667 h(-2)) led to a lower ethanol yield (0.40 g g(-1)) in the system where free cells were used, whereas with immobilized cells ethanol yields increased by 23 % (0.49 g g(-1)). Among the evaluated models, Monod and Levenspiel combined with Ghose and Tyagi models were found to be more appropriate for describing the kinetics of whey bioconversion into ethanol. These results may be useful in scaling up the process for ethanol production from whey.

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Dynamics of ethanol production from whey and whey permeate by immobilized strains of Kluyveromyces marxianus in batch and continuous bioreactors

Cited by 43 publications

References 40 publications

Whey-derived valuable products obtained by microbial fermentation

Whey-derived valuable products obtained by microbial fermentation

Toxicology and the biological role of methanol and ethanol: Current view

The modeling of ethanol production by Kluyveromyces marxianus using whey as substrate in continuous A-Stat bioreactors

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