Enhanced microalgal lipid production with media engineering of potassium nitrate as a nitrogen source

We investigated the possibility of utilizing both oleaginous yeast species accumulating large amounts of lipids (Yarrowia lipolytica, Rhodotorula glutinis, Trichosporon cutaneum,andCandidasp.) and traditional biotechnological nonoleaginous ones (Kluyveromyces polysporus, Torulaspora delbrueckii,andSaccharomyces cerevisiae) as potential producers of dietetically important major fatty acids. The main objective was to examine the cultivation conditions that would induce a high ratio of dietary fatty acids and biomass. Though genus-dependent, the type of nitrogen source had a higher influence on biomass yield than the C/N ratio. The nitrogen source leading to the highest lipid accumulation was potassium nitrate, followed by ammonium sulfate, which is an ideal nitrogen source supporting, in both oleaginous and nonoleaginous species, sufficient biomass growth with concomitantly increased lipid accumulation. All yeast strains displayed high (70–90%) content of unsaturated fatty acids in total cell lipids. The content of dietary fatty acids of interest, namely, palmitoleic acid and linoleic acid, reached inKluyveromycesandTrichosporonstrains over 50% of total fatty acids and the highest yield, over 280 mg per g of dry cell weight of these fatty acids, was observed inTrichosporonwith ammonium sulfate as nitrogen source at C/N ratio 70.

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EXOPOLYSACCHARIDE SYNTHESIS PRODUCTIVITY BY BACILLUS MUCILAGINOSUS DEPENDING ON THE NITROGEN SOURCE AND ORIGIN OF INOCULUM

Agriciltural microbiology ◽

10.35868/1997-3004.21.12-17 ◽

2015 ◽

Vol 21 ◽

pp. 12-17

Author(s):

I. M. Malinovska

Keyword(s):

Nitrogen Source ◽

Culture Medium ◽

Physiological State ◽

Bacterial Biomass ◽

Extracellular Polysaccharide ◽

Potassium Nitrate ◽

Bacillus Mucilaginosus ◽

Vegetative Cells ◽

Polysaccharide Synthesis ◽

Sporulation Process

It was established that Bacillus mucilaginosus C-3 requires introduction of nitrogen sourceinto the culture medium in form of nitrate as themost optimal for maximal accumulation of bacterial biomass and sporulation process. Introduction of the ammonium form was less efficient. It was shown that the intensity of nitrogensource use by B. mucilaginosus is highly depended on the physiological state of the inoculum cells. At sowing of spore inoculum theoptimal concentration of potassium nitrate was2.5 g/l resulting in 1010 cells/ml, while under theuse of vegetative cells the optimal concentrationof potassium nitrate was 1.0 g/l leading to theaccumulation of 109 cells/ml.Use of spore inoculum had ensured themaximum productivity of extracellular polysaccharide synthesis. With the higher number ofB. mucilaginosus subcultures in a vegetativestate the efficiency of the exopolysaccharidesynthesis has decreased: after the second passage — by 20.0 %, after the fourth — by 56.5 %,after the sixth — at 127.8 %. After eighth passage the culture loses its ability to synthesizepolysaccharide, especially on the medium withthe N : C ratio 1 : 3 and resume this ability onlyafter sporulation and the significant increase ofthe N : C ratio.

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Lab-scale assessment and adaptation of wastewater for cultivation of microalgal biomass for biodiesel production

10.51415/10321/1275 ◽

2015 ◽

Author(s):

◽

Luveshan Ramanna

Keyword(s):

Large Scale ◽

Physiological Stress ◽

Lipid Production ◽

Domestic Wastewater ◽

Potassium Nitrate ◽

Wastewater Effluent ◽

Biodiesel Production ◽

Available Nitrogen ◽

Microalgal Biomass ◽

Microalgal Culture

In light of the world’s declining fossil fuel reserves, the use of microalgal biodiesel has come to the forefront as a potentially viable alternative liquid fuel. The depleting freshwater reserves make the feasibility of this concept questionable. The use of wastewater reduces the requirement for depleting freshwater supplies. This project aimed to determine the viability of municipal domestic wastewater effluent as a substrate for microalgal growth, in order to generate an economical and environmentally friendly source of biofuel. Wastewater effluents from three domestic wastewater treatment plants were characterized in terms of known microalgal nutrients viz., ammonia, phosphate and nitrates. Phosphate concentrations varied throughout the year and were found to be low (< 3 mgL-1) whilst ammonia and nitrate concentrations ranged from 0 to 10 mgL-1 throughout the experimental period. These wastewaters were found to be suitable for cultivating microalgae. The study explored the cultivation of Chlorella sorokiniana on pre- and post-chlorinated domestic wastewater effluent to assess their potential as a medium for high microalgal culture density and lipid production. Post-chlorinated wastewater effluent was found to be superior to pre-chlorinated wastewater effluent, as evident by the higher biomass concentration. This wastewater stream did not contain high concentrations of bacteria when compared to pre-chlorinated wastewater effluent. Nitrogen is an essential nutrient required for regulating the growth and lipid accumulation in microalgae. Cultures growing in post-chlorinated effluent had a lifespan of 18 d. Residual nitrogen in wastewater effluent supported microalgal growth for limited periods. Supplementation using cheap, readily available nitrogen sources was required for optimal biomass and lipid production. Urea, potassium nitrate, sodium nitrate and ammonium nitrate were evaluated in terms of biomass and lipid production of C. sorokiniana. Urea showed the highest biomass yield of 0.216 gL-1 and was selected for further experimentation. Urea concentrations (0–10 gL-1) were assessed for their effect on growth and microalgal physiology using pulse amplitude modulated fluorometry. A concentration of 1.5 gL-1 urea produced 0.218 gL-1 biomass and 61.52 % lipid by relative fluorescence. Physiological stress was evident by the decrease in relative Electron Transport Rate from 10.45 to 6.77 and quantum efficiency of photosystem II charge separation from 0.665 to 0.131. Gas chromatography analysis revealed that C16:0, C18:0, C18:1, C18:2 and C18:3 were the major fatty acids produced by C. sorokiniana. Wastewater effluent has been considered an important resource for economical and sustainable microalgal biomass/lipid production. The study showed that C. sorokiniana was sufficiently robust to be cultivated on wastewater effluent supplemented with urea. The results indicate that supplemented wastewater effluent was an acceptable alternative to conventional media. Using a relatively cheap nitrogen source like urea can certainly improve the techno-economics of large scale biodiesel production.

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Effects of salinity and nitrogen source on growth and lipid production for a wild algal polyculture in produced water media

Algal Research ◽

10.1016/j.algal.2018.101406 ◽

2019 ◽

Vol 38 ◽

pp. 101406 ◽

Cited By ~ 8

Author(s):

Thomas C. Hopkins ◽

Enid J. Sullivan Graham ◽

Jonathan Schwilling ◽

Serena Ingram ◽

Stephen M. Gómez ◽

...

Keyword(s):

Nitrogen Source ◽

Produced Water ◽

Lipid Production ◽

Water Media

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Effect of Nitrogen Source on Biomass and Lipid Production of a Marine Microalga, <i>Nannochloropsis oceanica</i> IMET1

Green and Sustainable Chemistry ◽

10.4236/gsc.2015.52013 ◽

2015 ◽

Vol 05 (02) ◽

pp. 101-106 ◽

Cited By ~ 4

Author(s):

Yongxue Chi ◽

Feng Chen ◽

Yasuyuki Takiguchi

Keyword(s):

Nitrogen Source ◽

Lipid Production ◽

Nannochloropsis Oceanica ◽

Marine Microalga

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Photo-hydrogen and lipid production from lactate, acetate, butyrate, and sugar manufacturing wastewater with an alternative nitrogen source byRhodobactersp.KKU-PS1

PeerJ ◽

10.7717/peerj.6653 ◽

2019 ◽

Vol 7 ◽

pp. e6653 ◽

Cited By ~ 3

Author(s):

Thitirut Assawamongkholsiri ◽

Alissara Reungsang ◽

Sureewan Sittijunda

Keyword(s):

Fatty Acids ◽

Fatty Acid ◽

Methyl Ester ◽

Hydrogen Production ◽

Nitrogen Source ◽

Volatile Fatty Acids ◽

Lipid Production ◽

Monosodium Glutamate ◽

Sodium Glutamate ◽

Acetate Butyrate

Photo-hydrogen and lipid production from individual synthetic volatile fatty acids (VFAs) and sugar manufacturing wastewater (SMW) byRhodobactersp. KKU-PS1 with sodium glutamate or Aji-L (i.e., waste from the process of crystallizing monosodium glutamate) as a nitrogen source was investigated. Using individual synthetic VFAs, the maximum hydrogen production was achieved with Aji-L as a nitrogen source rather than sodium glutamate. The maximum hydrogen production was 1,727, 754 and 1,353 mL H2/L, respectively, using 25 mM of lactate, 40 mM of acetate and 15mM of butyrate as substrates. Under these conditions, lipid was produced in the range of 10.6–16.9% (w/w). Subsequently, photo-hydrogen and lipid production from SMW using Aji-L as nitrogen source was conducted. Maximal hydrogen production and hydrogen yields of 1,672 mL H2/L and 1.92 mol H2/mol substrate, respectively, were obtained. Additionally, lipid content and lipid production of 21.3% (w/w) and 475 mg lipid/L were achieved. The analysis of the lipid and fatty acid components revealed that triacyglycerol (TAG) and C18:1 methyl ester were the main lipid and fatty acid components, respectively, found inRhodobactersp. KKU-PS1 cells.

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Effect of Different Media and pH on Mycelial Growth of Sclerotium oryzae Causing Sheath Rot of Rice

South Asian Journal of Agriculture ◽

10.3329/saja.v7i1-2.56753 ◽

2019 ◽

pp. 67-72

Author(s):

Md Iqbal Ahmad ◽

Avijit Kumar Biswas ◽

Mst Sabiha Sultana ◽

Bidhan Chandro Sarker ◽

Chhoa Mondal

Keyword(s):

Carbon Source ◽

Nitrogen Source ◽

Radial Growth ◽

Mycelial Growth ◽

Culture Media ◽

Agar Medium ◽

Abiotic Factors ◽

Potassium Nitrate ◽

Pathology Laboratory ◽

Sheath Rot

Sclerotium oryzae causing sheath rot of rice, is one of the most important pathogen causing heavy crop losses in all the major rice growing areas of the world, including Bangladesh. The growth and reproduction of this soil borne pathogen depends on growing media and abiotic factors. Therefore, to evaluate the effect of different culture media and pH on mycelial radial growth of S. oryzae, the experiment was conducted in the Plant Pathology Laboratory of Agrotechnology Discipline, Khulna University, Khulna, Bangladesh. Performance of different media, carbon source and nitrogen source on radial mycelial growth was differed significantly. The maximum mycelial radial growth was observed on rice stem agar medium (70.40 mm) and minimum mycelial radial growth was recorded on cornmeal agar medium (50.60 mm). Considering carbon source, the maximum radial mycelial growth was found in glucose (66.40 mm) amended medium and no statistical differences were observed among sucrose, starch and Czapek dox agar containing medium. Based on nitrogen source, maximum radial mycelial growth was found in peptone medium (69.40 mm) but no statistical differences were exposed between Potassium nitrate (KNO3) and Sodium nitrate (NaNO3). pH- 6 played a vital role in radial mycelial growth (73.75 mm) of S. oryzae. South Asian J. Agric., 7(1&2): 67-72

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