scholarly journals Lipid yields from oleaginous yeasts isolated from the north Peruvian Andes by culture media non-limiting nitrogen

2021 ◽  
Vol 13 (2) ◽  
pp. 607-615
Author(s):  
Méndez Polo César Alexander ◽  
Quiroz Rodríguez Freddy Jonathan ◽  
Soriano Bernilla Bertha Soledad ◽  
Rojas-Padilla Carmen Rosa ◽  
Vásquez-Villalobos Víctor Javier

Oleochemicals can be obtained from oily yeasts due to their ability to produce a high lipid content. This research aimed to isolate them from the North Peruvian Andes with a lipid content greater than 20%. They were identified by sequencing internal transcribed spacer regions ITS of conserved ribosomal DNA (rDNA), evaluate their growth kinetics, biomass and lipid yields, using culture media with C/N 100:1+xylose (MS-1-7) and 2:1+glucose (MS-2-7). Growth kinetics up to the maximum stationary phase was evaluated using the parameterized Gompertz type II model. Rhodotorula glutinis, R. mucilaginosa, and R. kratochvilovae were selected. The C/N ratio in the culture medium influenced growth kinetics, biomass and lipids yields. With MS-1-7, a high specific growth rate (?max) was obtained, reaching the stationary phase between 6 to 9 h and the highest lipid accumulation between 23.1% and 31.5%. With the MS-2-7 medium, maximum biomass value obtained in the stationary phase between 37 and 51 h, which generated the highest biomass yields at the end of the entire process and lipid yield of 4.65, 5.59, and 8.80 g L-1 in the strains mentioned. There is potential to obtain high lipid yields using a culture media non-limiting nitrogen, examining not only the C/N ratio. But also, the quantities, nature of the components, and type of oleaginous yeasts taking care to avoid a high carbon concentration to prevent the Cabtree effect.

2017 ◽  
Author(s):  
Camille Litty ◽  
Fritz Schlunegger ◽  
Willem Viveen

Abstract. Twenty-one coastal rivers located on the western Peruvian margin were analyzed to determine the relationships between fluvial and environmental processes and sediment grain properties such as grain size, roundness and sphericity. Modern gravel beds were sampled along a north-south transect on the western side of the Peruvian Andes, and at each site the long a-axis and the intermediate b-axis of about 500 pebbles were measured. Morphometric properties such as river gradient, catchment size and discharge of each drainage basin were determined and compared against measured grain properties. Grain size data show a constant value of the D50 percentile all along the coast, but an increase in the D84 and D96 values and an increase in the ratio of the intermediate and the long axis from south to north. Our results then yield better-sorted and less spherical material in the south when compared to the north. No correlations were found between the grain size and the morphometric properties of the river basins when considering the data together. Grouping the results in a northern and southern group shows better-sorted sediments and lower D84 and D96 values for the southern group of basins. Within the two groups, correlations were found between the grain size distributions and morphometric basins properties. Our data indicates that fluvial transport is the dominant process controlling the erosion, transport and deposition of sediment in the southern basins while we propose a geomorphic control on the grain size properties in the northern basins. Sediment properties in the northern and southern basins could not be linked to differences in tectonic controls. On the other hand, the north-south trend in the grain size and in the b/a ratio seems controlled by a shift towards a more humid climate and towards a stronger El Nino impact in northern Peru. But, generally speaking, the resulting trends and differences in sediment properties seem controlled by differences in the complex geomorphic setting along the arc and forearc regions.


AMB Express ◽  
2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Bruno Vasconcelos ◽  
José Carlos Teixeira ◽  
Giuliano Dragone ◽  
José António Teixeira

2019 ◽  
Vol 13 (2) ◽  
pp. 112 ◽  
Author(s):  
Rifki Wahyu Kurnianto ◽  
Wiratni Budhijanto ◽  
Rochim Bakti Cahyono

Anaerobic digestion has been an attractive field of research in the era of energy crisis. Biogas, which is the product of anaerobic digestion, provides alternative energy, while at the same time it also prevents pollution due to organic waste accumulation. Among various organic wastes, dairy fat waste is a potential substrate for anaerobic digestion. Fat waste has high theoretical biogas potential because of its high lipid content. However, anaerobic digestion of organic waste with high lipid content is quite challenging. The main obstacle in anaerobic digestion of fat waste is its tendency to form insoluble floating layer on top of the liquid phase. This phenomenon hinders the access of hydrolytic bacteria to the substrate. Saponification is one of the methods to increase the solubility of the floating layer and hence to improve the availability of substrate for the bacteria. Saponification changes the lipid content into soap which has both polar and non-polar functional groups and the polar side will increase the solubility of the substrate in water. This study evaluated the effect of different dosage of base added as the reactant during saponification pre-treatment on the productivity of anaerobic digestion of dairy fat waste. The kinetics of the anaerobic digestion process was analyzed by mean of mathematical model. The variations of the alkaline dosages studied for saponification pre-treatment were 0.04 mol base/g sCOD; 0.02 mol base/g sCOD; and no pre-treatment for control reactor. This study proved that saponification increased the solubility of dairy fat waste. This result was confirmed by the hydrolysis constant value (kH) of 0.00782/day for reactor with saponification, which was twenty times of magnitude higher than the kH value of 0.00032/day in the reactor without saponification. However, the exposure to high pH during the saponification pre-treatment might somewhat inhibit indigenous acidogenic bacteria in the waste which results in lower methane yield in the reactors with saponification to be compared to the control reactor. A B S T R A KPeruraian anaerobik merupakan salah satu bidang riset yang sangat menarik perhatian dalam era krisis energi. Biogas tidak hanya menyediakan energi alternatif, tetapi juga dapat mencegah pencemaran akibat limbah organik. Limbah lemak susu adalah substrat yang potensial untuk proses peruraian anaerobik karena memiliki potensi biogas teoritis yang tinggi akibat kandungan lemaknya yang tinggi. Namun, peruraian anaerobik dari limbah organik dengan kandungan lemak yang tinggi memiliki tantangan tersendiri. Hambatan utama dalam peruraian anaerobik dari limbah lemak susu adalah kecenderungan untuk membentuk lapisan padatan yang tidak larut dan mengapung di bagian atas fase cair. Fenomena ini menghambat akses bakteri hidrolisis terhadap substrat. Saponifikasi adalah salah satu cara untuk meningkatkan kelarutan lapisan padatan tersebut, sehingga meningkatkan ketersediaan substrat untuk bakteri. Saponifikasi akan mengubah kandungan lemak menjadi sabun yang memiliki gugus fungsi polar maupun non-polar. Gugus fungsi yang bersifat polar akan meningkatkan kelarutan substrat dalam air. Studi ini mengevaluasi pengaruh dari berbagai dosis larutan basa yang ditambahkan sebagai reaktan selama perlakuan awal saponifikasi terhadap peruraian anaerobik limbah lemak susu. Kinetika proses peruraian anaerobik dianalisis dengan menggunakan model matematika. Variasi dosis yang diamati pengaruhnya untuk perlakuan awal saponifikasi adalah 0,04 mol basa/g sCOD; 0,02 mol basa/g sCOD; dan nol (tanpa perlakuan awal saponifikasi). Dari penelitian ini, terbukti bahwa saponifikasi berhasil meningkatkan kelarutan limbah lemak susu dan juga ditunjukkan oleh nilai konstanta hidrolisis (kH) 0,00782/hari lebih tinggi dua puluh kali lipat dibandingkan dengan nilai kH 0,00032/hari pada reaktor tanpa saponifikasi. Akan tetapi, penelitian ini juga mengindikasikan bahwa bakteri asidogenik bawaan substrat terhambat kinerjanya oleh paparan pH yang tinggi selama perlakuan awal saponifikasi berlangsung sehingga hasil gas metan yang diperoleh lebih rendah daripada reaktor kontrol.


2021 ◽  
pp. 3164-3169
Author(s):  
Mohamed M. M. El-Sokary ◽  
Al-Shimaa Al-H. H. El-Naby ◽  
Amal R. Abd El Hameed ◽  
Karima Gh. M. Mahmoud ◽  
T. H. Scholkamy

Background and Aim: Despite many trials, buffalo embryos have poor cryosurvivability because of their high lipid content. L-carnitine was found to be a lipid-reducing agent when added to oocyte and embryo culture media. The study aimed to determine the most effective concentration of L-carnitine to improve the oocyte developmental competence and cryotolerance of buffalo embryos. Materials and Methods: In vitro maturation and embryo culture media were supplemented with four concentrations of L-carnitine: 0 (control), 0.25, 0.5, and 1 mM. Good-quality embryos on 7 days were vitrified using mixtures of dimethyl sulfoxide and ethylene glycol at two concentrations (3.5 and 7 M). Results: The result showed that the cleavage and morula rates were significantly (p<0.05) higher in the 0.5 mM group. Blastocyst rates were significantly (p<0.05) higher at both 0.5 and 1 mM. The rates of viable embryos directly after thawing were significantly (p<0.05) increased in the 0.5 mM group. No significant difference was found in embryos cultured for 24 h after warming among all the groups. Conclusion: The addition of L-carnitine at a concentration of 0.5 mM to the culture media improves the oocyte developmental competence and cryotolerance of buffalo embryos directly after warming but not after 24 h of culture. Nevertheless, further studies must identify how L-carnitine exerts its beneficial micromechanisms.


2001 ◽  
Vol 204 (8) ◽  
pp. 1445-1457 ◽  
Author(s):  
S.J. Ressel

I examined the aerobic trunk muscles, which are used for call production, of male frogs from species that breed in different thermal environments to test the hypothesis that cold-adapted frogs should have fewer capillaries per unit mitochondrial volume in oxidative muscles than warm-adapted frogs because of reduced mitochondrial function at low temperatures. The species of interest were the cold-temperate Pseudacris crucifer and the warm-tropical Hyla microcephala in the family Hylidae, and the cold-temperate Rana sylvatica and the warm-temperate Rana clamitans in the family Ranidae. Trunk-muscle mitochondrial volume, V(V)(mt,f), was proportionally higher in species with higher mean calling rates (number of notes per hour), irrespective of the familial affinity of a species and the thermal environment in which it vocalized. Trunk-muscle capillary length density, J(V)(c,f), was significantly lower in P. crucifer than in H. microcephala because of significantly higher mean fiber area, a-(f). Conversely, trunk-muscle J(V)(c,f) was similar in the two ranid species. Using total capillary length, J(c), and total mitochondrial volume, V(mt,m), as a measure of maximal oxygen supply and demand, respectively, in trunk muscles, J(c)-to-V(mt,m) ratios were significantly lower in cold-adapted P. crucifer (4.3 km cm(−)(3)) and R. sylvatica (4.8 km cm(−)(3)) than in warm-adapted H. microcephala (7.1 km cm(−)(3)) and R. clamitans (6.4 km cm(−)(3)). In contrast, J(c)-to-V(mt,m) ratios in the more anaerobic gastrocnemius muscle of these species was not related to the thermal environment of a species, which may reflect capillaries conforming to microcirculatory functions, e.g. lactate removal, that take precedence over oxygen delivery. Mitochondrial cristae surface area, S(V)(im,mt), in P. crucifer trunk and gastrocnemius muscles (37.7+/−1.6 and 35.9+/−1.5 m(2)cm(−)(3) respectively) was, on average, similar to mammalian values, suggesting equivalent structural capacities of muscle mitochondria in these two taxa. Taken together, the present data suggest that trunk-muscle respiratory design may reflect a capillary supply commensurate with maximal levels of oxygen delivery set by mitochondria operating at different environmental temperatures. P. crucifer and H. microcephala trunk muscles were also characterized by a high lipid content, which contrasted with a near absence of trunk-muscle lipids in R. sylvatica and R. clamitans. The extraordinarily high lipid content of P. crucifer trunk muscles (26 % of muscle volume) may serve as an auxiliary oxygen pathway to mitochondria and thus compensate in part for this tissue's reduced capillary/fiber interface. The effect of potentially high depletion rates of trunk-muscle lipid stores on metabolic rates of male frogs while calling is discussed.


2021 ◽  
Vol 16 (10) ◽  
pp. 144-155
Author(s):  
Van Lal Michael Chhandama ◽  
Belur Kumudini Satyan

Microalgae emerged as a competent feedstock for biodiesel production because of high growth rate and lipid content. This work focuses on isolation of novel microalgal strain from different sources of water for the production of biodiesel. The isolated microalgae, Pleurastrum insigne possessed high lipid content (~28 % dcw), further optimized to 57.06 % dcw using a statistical design (CCD) under Response Surface Methodology. Lipid production was optimized by nutrient (nitrogen and phosphorus) and pH stress. The different type of fatty acids present in the optimized lipid was also profiled using GCMS. Biodiesel yield was found to be 82.14 % of the total lipid and the fuel properties tested have met IS, ASTM and EN biodiesel standards.


3 Biotech ◽  
2020 ◽  
Vol 10 (9) ◽  
Author(s):  
Nívea Moreira Vieira ◽  
Raquel Cristina Vieira dos Santos ◽  
Vanessa Kely de Castro Germano ◽  
Rafaela Zandonade Ventorim ◽  
Eduardo Luís Menezes de Almeida ◽  
...  

2014 ◽  
Vol 6 (4) ◽  
pp. 145-149 ◽  
Author(s):  
Lopez-Elias Jose Antonio ◽  
Carvallo Ruiz Maria Gisela ◽  
Estrada Raygoza Leticia Areli ◽  
Martinez Cordova Luis Rafael ◽  
Martinez-Porchas Marcel ◽  
...  

1998 ◽  
Vol 61 (8) ◽  
pp. 964-968 ◽  
Author(s):  
THOMAS P. OSCAR

Salmonella isolates were surveyed for their growth kinetics in a laboratory medium for the purpose of identifying isolates suitable for modeling experiments. In addition, the effect of holding stationary phase Salmonella cultures at different temperatures on their subsequent growth kinetics was evaluated for the purpose of developing a protocol to prevent the need for midnight sampling in modeling experiments. In Experiment 1, 16 isolates of Salmonella, 2 from the American Type Culture Collection (ATCC) and 14 from broiler operations, were surveyed for their growth kinetics in brain heart infusion (BHI) broth at 40°C. Lag time (P = 0.005) and growth rate (P = 0.022) were affected by identity of the isolate. Lag time ranged from 0.73 to 1.38 h, whereas growth rate ranged from 0.78 to 0.94 log10 CFU/ml/h. Overall, isolate S1 (Salmonella infantis from ATCC) was the fastest growing. In Experiment 2, 4 isolates of Salmonella, 1 from ATCC and 3 from broiler operations, were used to determine whether holding temperature influences subsequent growth kinetics. Salmonella isolates were grown to stationary phase at 37°C in BHI and then held for 24 h at 5, 22, or 37°C before dilution and reinitiation of growth in BHI at 37°C. Holding temperature did not alter or interact with identity of the isolate to alter subsequent growth kinetics. From the latter finding, a protocol was devised in which a dual-flask system is used to prevent the need for midnight sampling in modeling experiments. Similar to the results obtained in Experiment 1, identity of the isolate had only minor effects on growth kinetics in Experiment 2 indicating that all isolates examined were suitable for modeling experiments.


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