scholarly journals Assessment of Fatty Acids Profile and Omega-3 Polyunsaturated Fatty Acid Production by the Oleaginous Marine Thraustochytrid Aurantiochytrium sp. T66 Cultivated on Volatile Fatty Acids

Biomolecules ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 694 ◽  
Author(s):  
Alok Patel ◽  
Ulrika Rova ◽  
Paul Christakopoulos ◽  
Leonidas Matsakas

Thraustochytrids are considered natural producers of omega-3 fatty acids as they can synthesize up to 70% docosahexaenoic acids (DHA) of total lipids. However, commercial and sustainable production of microbial DHA is limited by elevated cost of carbon substrates for thraustochytrids cultivation. This problem can be addressed by utilizing low-cost renewable substrates. In the present study, growth, lipid accumulation and fatty acid profiles of the marine thraustochytrid Aurantiochytrium sp. T66 (ATCC-PRA-276) cultivated on volatile fatty acids (C1, formic acid; C2, acetic acid; C3, propionic acid; C4, butyric acid; C5, valeric acid and C6, caproic acid) and glucose as control were evaluated for the first time. This strain showed an inability to utilize C3, C5 and C6 as a substrate when provided at >2 g/L, while efficiently utilizing C2 and C4 up to 40 g/L. The highest cell dry weight (12.35 g/L) and total lipid concentration (6.59 g/L) were attained when this strain was cultivated on 40 g/L of butyric acid, followed by cultivation on glucose (11.87 g/L and 5.34 g/L, respectively) and acetic acid (8.70 g/L and 3.43 g/L, respectively). With 40 g/L butyric acid, the maximum docosahexaenoic acid content was 2.81 g/L, corresponding to 42.63% w/w of total lipids and a yield of 0.23 g/gcell dry weight (CDW). This marine oleaginous microorganism showed an elevated potential for polyunsaturated fatty acids production at higher acetic and butyric acid concentrations than previously reported. Moreover, fluorescence microscopy revealed that growth on butyric acid caused cell size to increase to 45 µm, one of the largest values reported for oleaginous microorganisms, as well as the presence of numerous tiny lipid droplets.

Author(s):  
Ikumi Umetani ◽  
Eshetu Janka ◽  
Michal Sposób ◽  
Chris J. Hulatt ◽  
Synne Kleiven ◽  
...  

AbstractBicarbonate was evaluated as an alternative carbon source for a green microalga, Tetradesmus wisconsinensis, isolated from Lake Norsjø in Norway. Photosynthesis, growth, and lipid production were studied using four inorganic carbon regimes: (1) aeration only, (2) 20 mM NaHCO3, (3) 5% (v/v) CO2 gas, and (4) combination of 20 mM NaHCO3 and 5% CO2. Variable chlorophyll a fluorescence analysis revealed that the bicarbonate treatment supported effective photosynthesis, while the CO2 treatment led to inefficient photosynthetic activity with a PSII maximum quantum yield as low as 0.31. Conversely, bicarbonate and CO2 treatments gave similar biomass and fatty acid production. The maximum growth rate, the final cell dry weight, and total fatty acids under the bicarbonate-only treatment were 0.33 (± 0.06) day−1, 673 (± 124) mg L−1 and 75 (± 5) mg g−1 dry biomass, respectively. The most abundant fatty acid components were α-linolenic acid and polyunsaturated fatty acids constituting 69% of the total fatty acids. The fatty acid profile eventuated in unsuitable biodiesel fuel properties such as high degree of unsaturation and low cetane number; however, it would be relevant for food and feed applications. We concluded that bicarbonate could give healthy growth and comparative product yields as CO2.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Ruiling Gao ◽  
Zifu Li ◽  
Xiaoqin Zhou ◽  
Wenjun Bao ◽  
Shikun Cheng ◽  
...  

Abstract Background Volatile fatty acids (VFAs) can be effective and promising alternate carbon sources for microbial lipid production by a few oleaginous yeasts. However, the severe inhibitory effect of high-content (> 10 g/L) VFAs on these yeasts has impeded the production of high lipid yields and their large-scale application. Slightly acidic conditions have been commonly adopted because they have been considered favorable to oleaginous yeast cultivation. However, the acidic pH environment further aggravates this inhibition because VFAs appear largely in an undissociated form under this condition. Alkaline conditions likely alleviate the severe inhibition of high-content VFAs by significantly increasing the dissociation degree of VFAs. This hypothesis should be verified through a systematic research. Results The combined effects of high acetic acid concentrations and alkaline conditions on VFA utilization, cell growth, and lipid accumulation of Yarrowia lipolytica were systematically investigated through batch cultures of Y. lipolytica by using high concentrations (30–110 g/L) of acetic acid as a carbon source at an initial pH ranging from 6 to 10. An initial pH of 8 was determined as optimal. The highest biomass and lipid production (37.14 and 10.11 g/L) were obtained with 70 g/L acetic acid, whereas cultures with > 70 g/L acetic acid had decreased biomass and lipid yield due to excessive anion accumulation. Feasibilities on high-content propionic acid, butyric acid, and mixed VFAs were compared and evaluated. Results indicated that YX/S and YL/S of cultures on butyric acid (0.570, 0.144) were comparable with those on acetic acid (0.578, 0.160) under alkaline conditions. The performance on propionic acid was much inferior to that on other acids. Mixed VFAs were more beneficial to fast adaptation and lipid production than single types of VFA. Furthermore, cultures on food waste (FW) and fruit and vegetable waste (FVW) fermentate were carried out and lipid production was effectively improved under this alkaline condition. The highest biomass and lipid production on FW fermentate reached 14.65 g/L (YX/S: 0.414) and 3.20 g/L (YL/S: 0.091) with a lipid content of 21.86%, respectively. By comparison, the highest biomass and lipid production on FVW fermentate were 11.84 g/L (YX/S: 0.534) and 3.08 g/L (YL/S: 0.139), respectively, with a lipid content of 26.02%. Conclusions This study assumed and verified that alkaline conditions (optimal pH 8) could effectively alleviate the lethal effect of high-content VFA on Y. lipolytica and significantly improve biomass and lipid production. These results could provide a new cultivation strategy to achieve simple utilizations of high-content VFAs and increase lipid production. Feasibilities on FW and FVW-derived VFAs were evaluated, and meaningful information was provided for practical applications.


1957 ◽  
Vol 49 (2) ◽  
pp. 171-179 ◽  
Author(s):  
A. John ◽  
G. Barnett ◽  
R. L. Reid

1. A study has been made of the production of volatile fatty acids obtainable from dried grass and its gross water-soluble and water-insoluble separates, in the artificial rumen, over two growing seasons.2. In contradistinction to fresh grass, the dried grass gives a consistent production of acetic acid proportionately greater than propionic acid, at all stages of maturity, but when aqueous extracts of the dried grass, and the resultant extracted grass, respectively, are examined separately in the artificial rumen, it is found that the former yield preponderating amounts of acetic acid while the latter give amounts of propionic acid equal to, or exceeding, the corresponding productions of acetic acid.3. An examination of the titration curves for the total acids obtained from the dried grass, extracted grass and grass extract runs, indicates an approach to an incomplete relationship between the residual carbohydrate in the extracted grass and cellulose, while the grass extract reveals itself as the chief source of acetic acid in the whole dried grass, the acid being formed very speedily at the start of the run.4. The suggested sources and some of the possible metabolic pathways involved in the formation of v.f.a. from grass are discussed in the text.


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Qian Fang ◽  
Sinmin Ji ◽  
Dingwu Huang ◽  
Zhouyue Huang ◽  
Zilong Huang ◽  
...  

This study explores the use of alkaline pretreatments to improve the hydrolyzation of rice husks to produce volatile fatty acids (VFAs). The study investigated the effects of reagent concentration and pretreatment time on protein, carbohydrates, and dissolved chemical oxygen demand (SCOD) dissolution after the pretreatment. The optimum alkaline pretreatment conditions were 0.30 g NaOH (g VS)−1, with a reaction time of 48 h. The experimental results show that when comparing the total VFA (TVFA) yields from the alkaline-pretreated risk husk with those from the untreated rice husk, over 14 d and 2 d, the maximum value reached 1237.7 and 716.0 mg·L−1 with acetic acid and propionic acid and with acetic acid and butyric acid, respectively. After the alkaline pretreatment, TVFAs increased by 72.9%; VFA accumulation grew over time. The study found that alkaline pretreatment can improve VFA yields from rice husks and transform butyric acid fermentation into propionic acid fermentation. The study results can provide guidelines to support the comprehensive utilization of rice husk and waste treatment.


1992 ◽  
Vol 70 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Branka Stevanovic ◽  
Pham Thi Anh Thu ◽  
Fernando Monteiro de Paula ◽  
Jorge Vieira da Silva

Endemic Balkan species Ramonda serbica and Ramonda nathaliae (Gesneriaceae) are rare resurrection flowering plants, known to withstand repeated cycles of desiccation–rehydration in their natural habitat. Analysis of their leaf lipids and fatty acids revealed a rather small amount of total lipids (15.8 mg/g dry weight in R. serbica and 19.5 in R. nathaliae) and galactolipids, particularly the monogalactosyl-diacylglycerol, considerably poorer in linolenic acid in comparison to other flowering plants (55% for R. nathaliae and 64% for R. serbica). Severe desiccation leads to a drastic loss in total lipids (76% in R. serbica and 71.5% in R. nathaliae), especially in monogalactosyl-diacylglycerol, but the recovery is extremely rapid and thorough upon the rewetting. A shift towards the more saturated oleic and linoleic acids in galactolipids occurs at a different time and to a different degree in the two species, and it is not evenly repaired. Ramonda serbica, known to be somewhat less resistant, shows a wider range of lipid changes. Key words: lipid, fatty acids, desiccation-tolerant plants, Ramonda serbica, Ramonda nathaliae.


2013 ◽  
Vol 69 (3) ◽  
pp. 495-503 ◽  
Author(s):  
M.-P. Zacharof ◽  
R. W. Lovitt

Waste effluents from anaerobic digesters of agricultural waste were treated with a range of membranes, including microfiltration and nanofiltration (NF), to concentrate volatile fatty acids (VFA). Microfiltration was applied successfully to produce sterile, particle-free solutions with a VFA concentration of 21.08 mM of acetic acid and 15.81 mM of butyric acid. These were further treated using a variety of NF membranes: NF270 (Dow Chemicals, USA), HL, DL, DK (Osmonics, USA) and LF10 (Nitto Denko, Japan), achieving retention ratios of up to 75%, and giving retentates of up to 53.94 mM of acetate and 28.38 mM of butyrate. DK and NF270 membranes were identified as the best candidates for VFA separation and concentration from these multicomponent effluents, both in terms of retention and permeate flux. When the effluents are adjusted to alkali conditions, the highest productivity, retention and flux were achieved at pH 7. At higher pH there was a significant reduction in flux.


1957 ◽  
Vol 8 (6) ◽  
pp. 691 ◽  
Author(s):  
RL Reid ◽  
JP Hogan ◽  
PK Briggs

Detailed data are presented on changes in the proportions of acetic, propionic, and butyric acids in the rumen after feeding on various diets. Pre-feeding proportions were constant on each diet but varied from a mixture of 72-76 per cent. acetic, 14-16 per cent. propionic, and 10-12 per cent. butyric acid on all-roughage diets to one of 63-65 per cent. acetic, 18-20 per cent. propionic, and 16-18 per cent. butyric acid on a diet containing 70 per cent. wheat grain. On all diets the proportion of propionic acid increased after feeding and reached a peak which coincided with the maximum level of total volatile fatty acids. The response of butyric acid was variable, low levels being recorded on a diet of lucerne chaff and on one containing a high proportion of cracked maize. The proportion of acetic acid always declined after feeding. These responses were modified in experiments on rations containing high proportions of wheaten starch, in which rumen pH fell below 5.0 as a result of lactic acid accumulation. When animals were first fed on such diets, a decline in rumen pH below 5.0-5.5 after feeding was always associated with a pronounced decline in the proportions of propionic and butyric acids, to levels as low as 8 and 5 per cent. respectively. Continued feeding of such diets did not affect the response of butyric acid, but there was evidence of a change in propionic acid production in response to low pH conditions, both in respect to short-term change during experiments in which low rumen pH levels were maintained for considerable periods and to long-term change when such diets were fed intermittently over considerable periods. The implications of these findings are discussed with respect to the effects of pH on individual volatile fatty acid production in the rumen, and on the qualitative nature of the microbial population and on their metabolic patterns.


1951 ◽  
Vol 2 (1) ◽  
pp. 92 ◽  
Author(s):  
GL McClymont

Volatile fatty acid isolated from nine samples of peripheral blood from four cows contained, on a molecular basis, from 90.0 to 97.0 per cent. of acetic acid (mean 93.3 per cent.). The remainder comprised, as mean values, propionic acid, 2.39 per cent.; butyric acid, 2.61 per cent.; and a group of at least three acids between butyric and octanoic, 1.84 per cent. The significance of the high proportion of acetic acid in the volatile fatty acid of bovine peripheral blood is discussed. Only traces of esterified acids lower than octanoic could be found in bovine blood lipides. Volatile fatty acids were found also in the blood of the rabbit, guinea pig, horse, and pig and in human plasma. Here again a high proportion of acetic acid was recorded. Volatile fatty acid isolated from nine samples of ruminal contents from two cows contained on a molecular basis from 52.3 to 69.0 per cent. of acetic acid (mean 60.0 per cent.). The remainder comprised, as mean values, propionic acid, 21.8 per cent.; butyric acid, 14.4 per cent.; and acids higher than butyric (apparently largely valeric and hesanoic), 3.8 per cent. This limited number of analyses indicated no gross effect of type of feed on the proportion of the acids in the rumen.


1957 ◽  
Vol 49 (2) ◽  
pp. 180-183 ◽  
Author(s):  
A. John ◽  
G. Barnett ◽  
R. L. Reid

1. The findings presented in two previous papers on the yields of volatile fatty acids, obtained by the action of rumen liquor in the artificial rumen, from fresh grass, dried grass and the water-soluble and water-insoluble separates of the latter, have been amplified by a consideration of the acids similarly obtained from specimens of chemically prepared crude fibre and cellulose, from four of the dried grass specimens.2. The proportions of different volatile fatty acids from grass crude fibre and grass cellulose resemble those obtained from cellulose powder, propionic acid being produced in greatest relative yield.3. A general review of these latter findings, in relation to those already presented, has been given.


RSC Advances ◽  
2015 ◽  
Vol 5 (62) ◽  
pp. 50033-50039 ◽  
Author(s):  
Xue Yang ◽  
Lei Wen ◽  
Xiang Liu ◽  
Si Chen ◽  
Yayi Wang ◽  
...  

Although many pretreatment methods are employed to enhance the hydrolysis of waste activated sludge (WAS), the bioconversion of soluble complex substrates needs improvement to produce higher volatile fatty acids (VFAs).


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