Cultivation modes for microbial oil production using oleaginous yeasts – A review

Karamerou, Eleni E.; Webb, Colin

doi:10.1016/j.bej.2019.107322

Cited by 66 publications

(37 citation statements)

References 128 publications

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“…In fed-batch cultivation processes, substrate feeding is one of the most important factors influencing lipid production [37]. The use of appropriate substrate feeding mode led to efficient conversion of the carbon source to desired products.…”

Section: Two-stage Fed-batch Cultivation In a 3 L Fermentermentioning

confidence: 99%

“…The use of appropriate substrate feeding mode led to efficient conversion of the carbon source to desired products. Moreover, the feeding time and the composition of the feeding solution affect the lipid productivity [35,37]. By modifying the feed rate, it is possible to control growth and lipid accumulation in oleaginous microorganisms [25,38].…”

Section: Two-stage Fed-batch Cultivation In a 3 L Fermentermentioning

confidence: 99%

“…Although, the pulse feeding of crude glycerol solution without auxiliary nutrients could result in an increasing C/N ratio of the medium which favors lipid accumulation; however, it dilutes cell concentration in the fermenter. Karamerou and Webb [37] suggested that the minimizing feeding volume by increasing feeding solution concentration could diminish the dilution effect; nevertheless, it could be lower by high cell density. As seen in Figure 4A, after crude glycerol solution was fed, cell concentration in the fermenter was diluted approximately 1.8-fold; however, cell density in the fermenter recovered within 24-48 h. When crude glycerol solution (147.5 g/L) was fed at 48 and 24 h after batch operation had begun (experiments 1 and 2, respectively), the cell mass increased to 33.2 and 31.0 g/L, respectively, after 240 h of cultivation, compared with the batch cultivation (30.3 g/L) ( Figure 4A).…”

Section: Two-stage Fed-batch Cultivation In a 3 L Fermentermentioning

confidence: 99%

“…However, it could be observed that when the start of the fed-batch stage was delayed to 72 h (experiment 3), a lower cell mass and lipid concentration of 26.3 and 13.3 g/L, respectively, were obtained. It would be due to that cells experience nutrient starvation until crude glycerol was fed at 72 h [37]. It was noted that crude glycerol was not completely consumed by R. fluvialis DMKU-SP314 and approximately 40 g/L crude glycerol remained in culture broth throughout the cultivation ( Figure 4E).…”

Section: Two-stage Fed-batch Cultivation In a 3 L Fermentermentioning

confidence: 99%

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Feeding Strategies of Two-Stage Fed-Batch Cultivation Processes for Microbial Lipid Production from Sugarcane Top Hydrolysate and Crude Glycerol by the Oleaginous Red Yeast Rhodosporidiobolus fluvialis

Poontawee

2020

Microorganisms

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Microbial lipids are able to produce from various raw materials including lignocellulosic biomass by the effective oleaginous microorganisms using different cultivation processes. This study aimed to enhance microbial lipid production from the low-cost substrates namely sugarcane top hydrolysate and crude glycerol by Rhodosporidiobolus fluvialis DMKU-SP314, using two-stage fed-batch cultivation with different feeding strategies in a 3 L stirred-tank fermenter. The effect of two feeding strategies of 147.5 g/L crude glycerol solution was evaluated including pulse feeding at different starting time points (48, 24, and 72 h after initiation of batch operation) and constant feeding at different dilution rates (0.012, 0.020, and 0.033 h−1). The maximum lipid concentration of 23.6 g/L and cell mass of 38.5 g/L were achieved when constant feeding was performed at the dilution rate of 0.012 h−1 after 48 h of batch operation, which represented 1.24-fold and 1.27-fold improvements in the lipid and cell mass concentration, respectively. Whereas, batch cultivation provided 19.1 g/L of lipids and 30.3 g/L of cell mass. The overall lipid productivity increased to 98.4 mg/L/d in the two-stage fed-batch cultivation. This demonstrated that the two-stage fed-batch cultivation with constant feeding strategy has the possibility to apply for large-scale production of lipids by yeast.

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Section: Two-stage Fed-batch Cultivation In a 3 L Fermentermentioning

confidence: 99%

Section: Two-stage Fed-batch Cultivation In a 3 L Fermentermentioning

confidence: 99%

Section: Two-stage Fed-batch Cultivation In a 3 L Fermentermentioning

confidence: 99%

Section: Two-stage Fed-batch Cultivation In a 3 L Fermentermentioning

confidence: 99%

See 2 more Smart Citations

Feeding Strategies of Two-Stage Fed-Batch Cultivation Processes for Microbial Lipid Production from Sugarcane Top Hydrolysate and Crude Glycerol by the Oleaginous Red Yeast Rhodosporidiobolus fluvialis

Poontawee

2020

Microorganisms

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“…From a process engineering angle, most authors reason that since achieving high cell-density is a prerequisite for high intracellular product titres, advanced cultivation modes, such as fed-batch, drawfill, continuous and two-stage fed-cultivations attain improved cell densities and consequently higher lipid titres [18]. Regulation of the feed rate and design of its composition delivers better carbon-tonitrogen ratio, allowing the stoichiometric requirement of carbon flux for growth to generate lipidfree cell mass and the excess carbon to lipid synthesis [11,19].…”

Section: Introductionmentioning

confidence: 99%

Using Techno-Economic Modelling to Determine the Minimum Cost Possible for a Microbial Palm Oil Substitute

Karamerou

Parsons

McManus

et al. 2020

Preprint

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Background Palm oil is the most commonly used crop oil worldwide, and is used predominantly for food, in the chemical industry and for biofuels. It is mainly cultivated in areas with biodiverse and carbon-rich rainforest which has given rise to large increases in greenhouse gas (GHG) emissions and significant impacts to biodiversity. There is therefore substantial interest in finding an alternative to palm oil. Heterotrophic single cell oils (SCOs) are one potential replacement as these are able to mimic the lipid profile of palm oil in a way that other terrestrial and exotic crop oils cannot. But, despite a large experimental research effort in this area, there are only a handful of techno-economic modelling publications. As such, there is little understanding of whether SCOs are, or could ever be, a potential competitive replacement to palm oil. To help address this question we designed a detailed model that coupled a hypothetical heterotroph (using the very best possible biological lipid production) with the largest and most efficient chemical plant design possible. Results Our base case gave a lipid selling price of $2.01 / kg for ~8,000 tonnes / year production, that could be reduced to $1.54 /kg on increasing production to ~48,000 tonnes of lipid a year. A range of scenarios to further reduce this cost were then assessed, including using a thermotolerant strain (reducing the cost from $1.54 /kg to $1.47 /kg), zero cost electricity ($ 1.48/kg), using non-sterile conditions ($1.05 / kg), wet extraction of lipids ($1.48 / kg), continuous production of extracellular lipid ($0.76 /kg) and selling the whole yeast cell, including recovering value for the protein and carbohydrate ($1.14 /kg). If co-products were produced alongside the lipid then the price could be effectively reduced to $0, depending on the amount of carbon funnelled away from lipid production, as long as the co-product could be sold in excess of $1/kg. Conclusions The model presented here represents an ideal case that which while not achievable in reality, importantly would not be able to be improved on, irrespective of the scientific advances in this area. From the scenarios explored, however, it should still be possible to produce lower cost SCOs, but research must start to be applied in three key areas, firstly designing products where the whole cell is used, displacing products that contain palm oil rather than attempting to produce an exact refined palm oil substitute. Secondly, further work on the product systems that produce lipids extracellularly in a continuous processing methodology or finally that create an effective biorefinery designed to produce a low molecular weight, bulk chemical, alongside the lipid. All other research areas will only ever give incremental gains rather than leading towards an economically competitive, sustainable, microbial oil.

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Biodiesel from Microorganisms: A Review

Chen

Nie

et al. 2021

Energy Tech

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As societies develop and industrialize, sources of energy such as natural gas, coal, and oil become increasingly important in daily life. Among all forms of energy, fossil fuels are the most important, being primary sources of energy, [1] and, given their high heating value and therefore high efficiency, indispensable to heating, transport, and manufacturing operations. Fossil fuels most frequently seen in daily life are oil, coal, and natural gas. In 2019, total fossil energy consumption in the world was 492.34 exajoules (1 exajoule ¼ 10 18 J), accounting for 84.3% of the total energy. [2] Global demand for fossil fuels is predicted to increase to 19.08 billion liters a day by 2040. [3] However, fossil fuels are nonrenewable, and their use is also associated with many other problems such as air pollution, global warming, and unsustainable development. By 2030, the concentration of the greenhouse gas CO 2 is predicted to increase by 80% of the level in 2007, [4] which will contribute a great deal to global warming. These considerations make it essential for researchers to find alternatives to fossil fuels.The USA Energy Independence and Security Act declared that 136.27 billion liters of renewable fuel will be produced by 2022 in USA, including 3.78 billion liters of biodiesel, 60.56 billion liters of cellulosic biofuels, and 56.78 billion liters of maizebased ethanol. [5] Among all the suitable replacements, biofuels have the highest potential, because they can use waste material as feedstock, and they are renewable. In 2019, world production of biofuels was 111.83 million liters of oil equivalent per day, and the growth rate was 5.1% more than that in 2018. [6] Biofuels include bioethanol, biodiesel, biogas, biohydrogen, etc. [7] Forest waste, waste cooking oil, and similar materials can be used for producing biodiesel. In recent decades, microorganisms have been tested for their suitability as feedstock to produce biodiesel, and have proved more advantageous than other materials. The properties of biodiesel are similar to, and in some cases better than, those of diesel. For example, biodiesel has a higher cetane number, a higher flash point, and almost no sulfur, unlike diesel. When used in engines, biodiesel emits smaller quantities of particulate matter and carbon monoxide. [8] In addition, biodiesel can be mixed with fossil diesel in any proportion. Biodiesel is the predominant biofuel in Europe and the Asia Pacific and accounted for 81% and 74% of the total biofuels, respectively, used in these regions in 2019. [2] World production of biofuels from 1999 to 2019 is shown in Figure 1, and 2 shows the production of ethanol and biodiesel in 2009 and 2019.However, many external and internal facts hinder the development of biodiesel. For example, biodiesel is less competitive than diesel in terms of price and also inferior to diesel in some ways; the oxygen content of biodiesel lowers its heat value; and some forms of biodiesel also emit larger quantities of particulate matter (PM) and NO x . These drawbacks mus...

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Cultivation modes for microbial oil production using oleaginous yeasts – A review

Cited by 66 publications

References 128 publications

Feeding Strategies of Two-Stage Fed-Batch Cultivation Processes for Microbial Lipid Production from Sugarcane Top Hydrolysate and Crude Glycerol by the Oleaginous Red Yeast Rhodosporidiobolus fluvialis

Feeding Strategies of Two-Stage Fed-Batch Cultivation Processes for Microbial Lipid Production from Sugarcane Top Hydrolysate and Crude Glycerol by the Oleaginous Red Yeast Rhodosporidiobolus fluvialis

Using Techno-Economic Modelling to Determine the Minimum Cost Possible for a Microbial Palm Oil Substitute

Biodiesel from Microorganisms: A Review

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