scholarly journals Bacterial diversity dynamics in microbial consortia selected for lignin utilization

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0255083
Author(s):  
Isis Viana Mendes ◽  
Mariana Botelho Garcia ◽  
Ana Carolina Araújo Bitencourt ◽  
Renata Henrique Santana ◽  
Philippe de Castro Lins ◽  
...  
Keyword(s):  
Carbon Source ◽  
Lignin Degradation ◽  
Culture Media ◽  
Variable Temperature ◽  
Kraft Lignin ◽  
Microbial Consortia ◽  
Bacterial Consortia ◽  
Different Temperatures ◽  
Enrichment Protocol ◽  
Defined Culture

Lignin is nature’s largest source of phenolic compounds. Its recalcitrance to enzymatic conversion is still a limiting step to increase the value of lignin. Although bacteria are able to degrade lignin in nature, most studies have focused on lignin degradation by fungi. To understand which bacteria are able to use lignin as the sole carbon source, natural selection over time was used to obtain enriched microbial consortia over a 12-week period. The source of microorganisms to establish these microbial consortia were commercial and backyard compost soils. Cultivation occurred at two different temperatures, 30°C and 37°C, in defined culture media containing either Kraft lignin or alkaline-extracted lignin as carbon source. iTag DNA sequencing of bacterial 16S rDNA gene was performed for each of the consortia at six timepoints (passages). The initial bacterial richness and diversity of backyard compost soil consortia was greater than that of commercial soil consortia, and both parameters decreased after the enrichment protocol, corroborating that selection was occurring. Bacterial consortia composition tended to stabilize from the fourth passage on. After the enrichment protocol, Firmicutes phylum bacteria were predominant when lignin extracted by alkaline method was used as a carbon source, whereas Proteobacteria were predominant when Kraft lignin was used. Bray-Curtis dissimilarity calculations at genus level, visualized using NMDS plots, showed that the type of lignin used as a carbon source contributed more to differentiate the bacterial consortia than the variable temperature. The main known bacterial genera selected to use lignin as a carbon source were Altererythrobacter, Aminobacter, Bacillus, Burkholderia, Lysinibacillus, Microvirga, Mycobacterium, Ochrobactrum, Paenibacillus, Pseudomonas, Pseudoxanthomonas, Rhizobiales and Sphingobium. These selected bacterial genera can be of particular interest for studying lignin degradation and utilization, as well as for lignin-related biotechnology applications.

scholarly journals The Hybrid Strategy of Thermoactinospora rubra YIM 77501T for Utilizing Cellulose as a Carbon Source at Different Temperatures

2017 ◽  
Vol 8 ◽  
Author(s):  
Yi-Rui Yin ◽  
Zhao-Hui Meng ◽  
Qing-Wen Hu ◽  
Zhao Jiang ◽  
Wen-Dong Xian ◽  
...  
Keyword(s):  
Carbon Source ◽  
Hybrid Strategy ◽  
Different Temperatures

Degradation of natural and Kraft lignins by the microflora of soil and water

1977 ◽  
Vol 23 (4) ◽  
pp. 434-440 ◽  
Author(s):  
Don L. Crawford ◽  
Suellen Floyd ◽  
Anthony L. Pometto III ◽  
Ronald L. Crawford
Keyword(s):  
Molecular Weight ◽  
Microbial Degradation ◽  
Lignin Degradation ◽  
Kraft Lignin ◽  
Lignin Biodegradation ◽  
Incubation Periods ◽  
Molecular Weight Fractions ◽  
Soil And Water ◽  
Different Molecular Weight ◽  
Microbial Attack

The comparative rates of microbial degradation 14C-lignin-labeled lignocelluloses and 14C-Kraft lignins were investigated using selected soil and water samples as sources of microorganisms. Natural lignocelluloses containing 14C primarily in their lignin components were prepared by feeding plants uniformly labeled L-[14C]phenylalanine through their cut stems. 14C-Kraft lignins were prepared by pulping lignin-labeled lignocelluloses. Rates of lignin biodegradation were determined by monitoring 14CO2 evolution from incubation mixtures over incubation periods of up to 1000 h. Observed rates of lignin degradation were slow in all cases. Kraft lignins appeared more resistant to microbial attack than natural lignins, even though they were decomposed more rapidly during the first 100–200 h of incubation. Similar degradation patterns were observed in both soil and water. Individual samples, however, varied greatly in their overall rates of degradation of either lignin type. A Kraft-lignin preparation was separated into a variety of molecular weight fractions by column chromatography on LH-20 Sephadex and the biodegradability of the different molecular weight fractions determined. The lower molecular weight fractions of the Kraft lignin were decomposed at a significantly faster rate by the microflora of soil than were the fractions of higher molecular weight.

scholarly journals Experimental study on the compression characteristics of soft soil based on low temperature effect

2021 ◽  
Vol 9 (4B) ◽  
Author(s):  
Jian Zhang ◽  
◽  
Chunpeng Han ◽  
Jiayi Tian ◽  
Qingjie Dong ◽  
...  
Keyword(s):  
Low Temperature ◽  
Phase Change ◽  
Compression Test ◽  
Variable Temperature ◽  
Soft Soil ◽  
Test Methods ◽  
Variable Load ◽  
Compression Tests ◽  
Different Temperatures ◽  
Freezing Condition

Based on the characteristics of long annual freezing time and short suitable construction period of soft soil in cold region, this paper discusses the feasibility of foundation treatment of soft soil in freezing-thawing layer under freezing condition. The deformation characteristics of soft soil in freezing-thawing layer in Hulunbuir area in China are studied by using two compression test methods, namely, constant temperature and variable load (CTVL) test, variable temperature and variable load (VTVL) test. The compressibility indexes under different temperatures and consolidation pressures are obtained. The research shows that the freezing-thawing soft soil has large compressibility, the maximum strain of CTVL test is 19.89%, and the maximum compression of VTVL test can reach 18.16%. The results of CTVL compression tests show that when the soil temperature is in the range of severe phase change (-1.5℃-0℃), the temperature change has the greatest influence on the compression coefficient of soil. The result of VTVL compression test shows that some additional deformation occurs under the action of low temperature. The additional deformation is further increased when the soil is under high consolidation pressure and in the severe phase change (-1.5℃-0℃).

Growth and Differentiation of Rabbit Blastocysts in Defined Culture Media

1983 ◽  
pp. 371-386 ◽  
Author(s):  
H. M. Beier ◽  
U. Mootz ◽  
B. Fischer ◽  
R. Ströbele-Müller
Keyword(s):  
Culture Media ◽  
Defined Culture

scholarly journals Lipid accumulation capability of typical non‐acclimated activated sludge microbial consortia using methane gas as secondary carbon source

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Dhan Lord B. Fortela ◽  
Wayne Sharp ◽  
Emmanuel Revellame ◽  
Andrei Chistoserdov ◽  
William Holmes ◽  
...  
Keyword(s):  
Carbon Source ◽  
Activated Sludge ◽  
Lipid Accumulation ◽  
Microbial Consortia ◽  
Methane Gas ◽  
Acclimated Activated Sludge ◽  
Secondary Carbon

136 ADDITION OF LOW DENSITY LIPOPROTEIN TO CHEMICALLY DEFINED PORCINE EMBRYO CULTURE MEDIUM CAN PARTIALLY REPLACE BOVINE SERUM ALBUMIN

2008 ◽  
Vol 20 (1) ◽  
pp. 148
Author(s):  
L. D. Spate ◽  
K. A. Walker ◽  
C. E. McHughes ◽  
R. S. Prather
Keyword(s):  
Embryo Culture ◽  
Culture Medium ◽  
Culture Media ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Blastocyst Stage ◽  
Differential Staining ◽  
Low Density ◽  
Cell Stage ◽  
Defined Culture

Embryo culture media typically contain undefined biologicals such as BSA. Our goal is to develop chemically defined culture media that are based on the biology and physiology of the embryo. To that end we evaluated the presence of message in embryos at various stages of development and determined that the message for the low density lipoprotein receptor (LDLR) increased from the germinal vesicle and 4-cell stage to the blastocyst stage of porcine embryogenesis. Thus, this study was conducted to determine if the addition of low density lipoprotein (LDL) would enhance the development and quality of in vitro produced porcine embryos in an already chemically defined culture medium. Slaughterhouse ovaries were aspirated, cumulous–oocyte complexes (COC) identified, and the COC were matured for 42 h in M199 base medium supplemented with EGF, FSH, and LH. Metaphase II oocytes were then selected. Fertilization was then preformed in modified Tris buffered medium and cocultured with 0.25 � 106/mL frozen thawed porcine semen for 5 h. The presumptive zygotes were then transferred to either porcine zygote medium with 0.3% BSA or 0.1% PVA (PZM3, PZM4). After 28 h, cleaved embryos were then sorted into six treatment groups (1. PZM3, 2. PZM3 + 20 µg mL–1 LDL, 3. PZM4, 4. PZM4 + 10 µg mL–1 LDL, 5. PZM4 + 20 µg mL–1 LDL, 6. PZM4 + 50 µg mL–1 LDL). The embryos were cultured in 5%O2 5%CO2 90%N until day 7. The percentage of development to the blastocyst stage was determined and analyzed with the SAS Proc GENMOD Procedure (a–cP ≤ 0.05). The percentage blastocyst was 51.3 � 0.09a, 51.6 � 0.09a, 33.1 � 0.99c, 35.8 � 0.09c, 36.9 � 0.09c, and 41.3 � 0.06b, for treatments 1–6, respectively. Culture in PZM4 (without BSA) significantly reduced development. However, addition of 50 µg mL–1 of LDL to PZM4 improved development above PZM4 alone. We interpret these data to indicate that a high concentration of LDL in the PZM4 media did improve embryo development and that LDL could partially substitute for BSA. Differential staining was performed on the blastocysts, and preliminary results suggest that the ICM to trophectoderm ratio in the high LDL treatment group is closer to the ratio found in in vivo produced embryos. This project was supported by USDA CSREES NRI (2006-35203-17282) and Food for the 21st Century.

Chemically defined culture media: rational recipes or witches' brew?

1996 ◽  
Vol 6 (0) ◽  
pp. 111
Author(s):  
Jeroen Van Bergen ◽  
Egbert A. J. F. Lakke
Keyword(s):  
Culture Media ◽  
Defined Culture

The effect of temperature on the development and survival of the infective larvae of Strongyloides ratti Sandground, 1925

Parasitology ◽  
1968 ◽  
Vol 58 (3) ◽  
pp. 641-651 ◽  
Author(s):  
J. Barrett
Keyword(s):  
Culture Media ◽  
Maximum Activity ◽  
Temperature Adaptation ◽  
Effect Of Temperature ◽  
Free Living ◽  
Larval Stages ◽  
Infective Larvae ◽  
Significant Difference ◽  
Show Maximum Activity ◽  
Different Temperatures

The development of the free-living infective larvae of a homogonic strain Strongyloides ratti is described.The larvae develop only between 15 and 34 °C. Transfer experiments show the temperature block to be in the preparation for the second moult.Within the temperature range 15–34 °C, increasing the temperature speeds up the rate of development of all the larval stages equally, the Q10 for development being 2·5.The maximum percentage development occurs at 20 °C. The percentage development is highest in faeces–peat culture (95% development at 20 °C), whilst the percentage development in charcoal and vermiculite cultures is about the same (75% development at 20 °C.).Larvae grown on charcoal cultures are larger than those grown on vermiculite, which are larger than those grown on peat. No significant difference was found in the length:oesophagus and length:width ratios or in the variability of larvae grown at different temperatures or on different culture media.Different worm densities in the cultures of from 2000 to 10000 larvae per g of culture did not affect either the size of the infective larve or the percentage development.The optimum temperature for survival is 15 °C. Worms grown at 20 °C lived longer than worms grown at any other temperature. There was no evidence of temperature adaptation by the larvae.The infective larvae are positively thermotactic, and show maximum activity at 37 °C.I should like to thank my supervisor, Dr Tate, for his advice and encouragement. The work was carried out during the tenure of a Medical Research Council Scholarship.

scholarly journals Conformational study of a series of 6-substituted 5,6,7,12-tetrahydrodibenzo[a,d]-cyclooctenes by nuclear magnetic resonance spectroscopy

1977 ◽  
Vol 55 (19) ◽  
pp. 3456-3463 ◽  
Author(s):  
Roger N. Renaud ◽  
John W. Bovenkamp ◽  
Robert R. Fraser ◽  
Jean-Louis A. Roustan
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Variable Temperature ◽  
Resonance Spectroscopy ◽  
Proton Nmr Spectroscopy ◽  
Conformational Study ◽  
Methyl Derivative ◽  
Conformational Properties ◽  
Different Temperatures ◽  
Keto Derivative ◽  
Twist Boat

The conformational properties of seven 5,6,7,12-tetrahydrodibenzo[a,d]cyclooctenes bearing substituents at C-6 have been studied using variable temperature proton nmr spectroscopy. The position of the equilibrium between boat-chair (BC) and twist-boat (TB) conformers has been measured in several solvents. In contrast to the unsubstituted dibenzocyclooctene, appreciable amounts of TB conformer are present when C-6 is substituted by alkyl, hydroxy, or cyano substituents. Measurements at different temperatures showed the TB form to possess the greater entropy. Barriers to the BC → TB interconversion were determined by coalescence studies, using both approximate and complete line shape methods. Barriers ranged from 10.1 kcal/mol for the 6-keto derivative to 16.7 kcal/mol for the 6-hydroxy-6-methyl derivative.

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