scholarly journals Isolation and characterisation of Methylocystis spp. for poly-3-hydroxybutyrate production using waste methane feedstocks

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bashir L. Rumah ◽  
Christopher E. Stead ◽  
Benedict H. Claxton Stevens ◽  
Nigel P. Minton ◽  
Alexander Grosse-Honebrink ◽  
...  

AbstractWaste plastic and methane emissions are two anthropogenic by-products exacerbating environmental pollution. Methane-oxidizing bacteria (methanotrophs) hold the key to solving these problems simultaneously by utilising otherwise wasted methane gas as carbon source and accumulating the carbon as poly-3-hydroxybutyrate, a biodegradable plastic polymer. Here we present the isolation and characterisation of two novel Methylocystis strains with the ability to produce up to 55.7 ± 1.9% poly-3-hydroxybutyrate of cell dry weight when grown on methane from different waste sources such as landfill and anaerobic digester gas. Methylocystis rosea BRCS1 isolated from a recreational lake and Methylocystis parvus BRCS2 isolated from a bog were whole genome sequenced using PacBio and Illumina genome sequencing technologies. In addition to potassium nitrate, these strains were also shown to grow on ammonium chloride, glutamine and ornithine as nitrogen source. Growth of Methylocystis parvus BRCS2 on Nitrate Mineral Salt (NMS) media with 0.1% methanol vapor as carbon source was demonstrated. The genetic tractability by conjugation was also determined with conjugation efficiencies up to 2.8 × 10–2 and 1.8 × 10–2 for Methylocystis rosea BRCS1 and Methylocystis parvus BRCS2 respectively using a plasmid with ColE1 origin of replication. Finally, we show that Methylocystis species can produce considerable amounts of poly-3-hydroxybutyrate on waste methane sources without impaired growth, a proof of concept which opens doors to their use in integrated bio-facilities like landfills and anaerobic digesters.

Marine Drugs ◽  
2021 ◽  
Vol 20 (1) ◽  
pp. 8
Author(s):  
Heiðrún Eiríksdóttir ◽  
Magnús Örn Stefánsson ◽  
Hjörleifur Einarsson

The demand for novel sources of marine oils, which contain polyunsaturated fatty acids (PUFAs), has increased due to the realization of the importance of PUFAs, e.g., docosahexaenoic acid (DHA), in the human diet. However, the natural supply is limited. By-product peptones (BYPP) intended as a growth medium for the PUFA-producing strain Sicyoidochytrium minutum of family Thraustochytriaceae were produced after several experiments on the pancreatic digestion of bovine lungs and spleens. S. minutum was able to grow in a medium containing BYPP made from the pancreatic digestion of lung and spleen with glycerol, resulting in 1.14 ± 0.03 g cell dry weight (CDW)/L and 1.44 ± 0.24 g CDW/L, respectively, after 5 days of incubation at 25 °C, compared to 1.92 ± 0.25 g CDW/L in Basal Medium (BM) containing tryptone, peptone, and glycerol. The lipid content, obtained after growth in lung BYPP media with glycerol as a carbon source, was significantly higher (28.17% ± 1.33 of dry weight) than in the control basal medium (BM) (21.72% ± 2.45); however, DHA as a percentage of total fatty acids was lower in BYPP than in the control BM (25.24% ± 1.56 and 33.02% ± 2.37, respectively). It is concluded that low-value by-products from abattoirs can be used as ingredients for the cultivation of oligogenic Thraustochytriaceae.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Olga Marchut-Mikołajczyk ◽  
Piotr Drożdżyński ◽  
Arkadiusz Polewczyk ◽  
Wojciech Smułek ◽  
Tadeusz Antczak

Abstract Background Microbial surfactants called biosurfactants, thanks to their high biodegradability, low toxicity and stability can be used not only in bioremediation and oil processing, but also in the food and cosmetic industries, and even in medicine. However, the high production costs of microbial surfactants and low efficiency limit their large-scale production. This requires optimization of management conditions, including the possibility of using waste as a carbon source, such as food processing by-products. This papers describes the production and characterization of the biosurfactant obtained from the endophytic bacterial strain Bacillus pumilus 2A grown on various by-products of food processing and its potential applications in supporting plant growth. Four different carbon and nitrogen sources, pH, inoculum concentration and temperature were optimized within Taguchi method. Results Optimization of bioprocess within Taguchi method and experimental analysis revealed that the optimal conditions for biosurfactant production were brewer’s spent grain (5% w/v), ammonium nitrate (1% w/v), pH of 6, 5% of inoculum, and temperature at 30 °C, leading to 6.8 g/L of biosurfactant. Based on gas chromatography–mass spectrometry and Fourier transform infrared spectroscopy analysis produced biosurfactant was determined as glycolipid. Obtained biosurfactant has shown high and long term thermostability, surface tension of 47.7 mN/m, oil displacement of 8 cm and the emulsion index of 69.11%. The examined glycolipid, used in a concentration of 0.2% significantly enhanced growth of Phaseolus vulgaris L. (bean), Raphanus L. (radish), Beta vulgaris L. (beetroot). Conclusions The endophytic Bacillus pumilus 2A produce glycolipid biosurfactant with high and long tem thermostability, what makes it useful for many purposes including food processing. The use of brewer’s spent grain as the sole carbon source makes the production of biosurfactants profitable, and from an environmental point of view, it is an environmentally friendly way to remove food processing by products. Glycolipid produced by endophytic Bacillus pumilus 2A significantly improve growth of Phaseolus vulgaris L. (bean), Raphanus L. (radish), Beta vulgaris L. (beetroot). Obtained results provide new insight to the possible use of glycolipids as plant growth promoting agents.


Heliyon ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. e07079
Author(s):  
Joel Romial Ngouénam ◽  
Chancel Hector Momo Kenfack ◽  
Edith Marius Foko Kouam ◽  
Pierre Marie Kaktcham ◽  
Rukesh Maharjan ◽  
...  

2010 ◽  
Vol 76 (9) ◽  
pp. 2884-2894 ◽  
Author(s):  
Efraín Manilla-Pérez ◽  
Alvin Brian Lange ◽  
Stephan Hetzler ◽  
Marc Wältermann ◽  
Rainer Kalscheuer ◽  
...  

ABSTRACT In many microorganisms, the key enzyme responsible for catalyzing the last step in triacylglycerol (TAG) and wax ester (WE) biosynthesis is an unspecific acyltransferase which is also referred to as wax ester synthase/acyl coenzyme A (acyl-CoA):diacylglycerol acyltransferase (WS/DGAT; AtfA). The importance and function of two AtfA homologues (AtfA1 and AtfA2) in the biosynthesis of TAGs and WEs in the hydrocarbon-degrading marine bacterium Alcanivorax borkumensis SK2 have been described recently. However, after the disruption of both the AtfA1 and AtfA2 genes, reduced but substantial accumulation of TAGs was still observed, indicating the existence of an alternative TAG biosynthesis pathway. In this study, transposon-induced mutagenesis was applied to an atfA1 atfA2 double mutant to screen for A. borkumensis mutants totally defective in biosynthesis of neutral lipids in order to identify additional enzymes involved in the biosynthesis of these lipids. At the same time, we have searched for a totally TAG-negative mutant in order to study the function of TAGs in A. borkumensis. Thirteen fluorescence-negative mutants were identified on Nile red ONR7a agar plates and analyzed for their abilities to synthesize lipids. Among these, mutant 2 M131 was no longer able to synthesize and accumulate TAGs if pyruvate was used as the sole carbon source. The transposon insertion was localized in a gene encoding a putative cytochrome c family protein (ABO_1185). Growth and TAG accumulation experiments showed that the disruption of this gene resulted in the absence of TAGs in 2 M131 but that growth was not affected. In cells of A. borkumensis SK2 grown on pyruvate as the sole carbon source, TAGs represented about 11% of the dry weight of the cells, while in the mutant 2 M131, TAGs were not detected by thin-layer and gas chromatography analyses. Starvation and lipid mobilization experiments revealed that the lipids play an important role in the survival of the cells. The function of neutral lipids in A. borkumensis SK2 is discussed.


Author(s):  
M O Oyewale

The mycelial dry weight and dinitrosalicylic acid (D.N.S.A.) method was used to determine growth and amylase production by Aspergillus flavus grown on different carbon sources. Growth of the fungus was determined at 24 h intervals over a period of six days by the dry mycelial weight methods, while the amylase activity in the culture filtrates of A. flavus was determined by the D.N.S.A method. A total of 45 samples were prepared to determine growth and amylase activity of Aspergillus flavus grown on different carbon sources. The concentration of the various carbon sources ranges between 0.4 to 2% W/V. Duncan’s multiple range test was used to determine the level of significance of the different carbon sources for effective growth and amylase production by Aspergillus flavus. Aspergillus flavus demonstrated the capability to produce significant growth and amylase activities in the medium containing soluble starch, sorghum and cassava peel as sole carbon source. The amount of mycelial dry weight produced from soluble starch, sorghum and cassava peel is significantly higher than those produced from other carbon sources. The data revealed that there is a correlation between growth and amylase production by Aspergillus flavus. The available data from this study showed that soluble starch is the best carbon source for optimum growth and amylase production by A flavus while sorghum and cassava peel are close substitute for optimum growth and amylase production by Aspergillus flavus. Keywords: Growth, amylase activity and Aspergillus flavus


Microbiology ◽  
2000 ◽  
Vol 81 (1) ◽  
pp. 145-149 ◽  
Author(s):  
Y. Okon ◽  
I. Chet ◽  
Naomi Kislev ◽  
Y. Henis

SUMMARY A significant increase in mycelial dry weight and a decrease in production of extracellular glucan were observed when lactose was added to a submerged culture of Sclerotium rolfsii grown in a liquid glucose-synthetic medium. When added as a sole carbon source, lactose at 2·5% (w/v) induced the formation of dark, spherical, compact bodies. The ultrastructure of these bodies is compared with that of sclerotia formed on solid media.


Agronomy ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 420 ◽  
Author(s):  
Domenico Ronga ◽  
Enrico Francia ◽  
Giulio Allesina ◽  
Simone Pedrazzi ◽  
Massimo Zaccardelli ◽  
...  

Although compost and biochar received high attention as growing media, little information is available on the potential of vineyard by-products for the production and use of composted solid digestate (CSD) and biochar (BC). In the present study, two experiments are reported on CSD and BC mixed with commercial peat (CP) for grapevine planting material production. Four doses (0, 10%, 20%, 40% vol.) of CSD and BC were assessed in the first and second experiment, respectively. CSD mixed at a dose of 10% recorded the highest values of shoot dry weight (SDW) and a fraction of total dry biomass allocated to shoot (FTS), both cropping bench-graft and bare-rooted vine. On the other hand, CSD mixed at a dose of 40% displayed the highest values of SDW and FTS, cropping two-year-old vine. BC used at a dose of 10% improved SDW, root dry weight, total dry weight, FTS, shoot diameter, and height on bare-rooted vine. The present study shows that CSD and BC, coming from the valorization of vineyard by-products, can be used in the production of innovative growing media suitable for nursery grapevine production. Further studies are needed to assess the combined applications of CSD and BC in the same growing media.


2006 ◽  
Vol 72 (6) ◽  
pp. 3901-3907 ◽  
Author(s):  
P. J. Maxfield ◽  
E. R. C. Hornibrook ◽  
R. P. Evershed

ABSTRACT A time series phospholipid fatty acid (PLFA) 13C-labeling study was undertaken to determine methanotrophic taxon, calculate methanotrophic biomass, and assess carbon recycling in an upland brown earth soil from Bronydd Mawr (Wales, United Kingdom). Laboratory incubations of soils were performed at ambient CH4 concentrations using synthetic air containing 2 parts per million of volume of 13CH4. Flowthrough chambers maintained a stable CH4 concentration throughout the 11-week incubation. Soils were analyzed at weekly intervals by gas chromatography (GC), GC-mass spectrometry, and GC-combustion-isotope ratio mass spectrometry to identify and quantify individual PLFAs and trace the incorporation of 13C label into the microbial biomass. Incorporation of the 13C label was seen throughout the experiment, with the rate of incorporation decreasing after 9 weeks. The δ13C values of individual PLFAs showed that 13C label was incorporated into different components to various extents and at various rates, reflecting the diversity of PLFA sources. Quantitative assessments of 13C-labeled PLFAs showed that the methanotrophic population was of constant structure throughout the experiment. The dominant 13C-labeled PLFA was 18:1ω7c, with 16:1ω5 present at lower abundance, suggesting the presence of novel type II methanotrophs. The biomass of methane-oxidizing bacteria at optimum labeling was estimated to be about 7.2 � 106 cells g−1 of soil (dry weight). While recycling of 13C label from the methanotrophic biomass must occur, it is a slower process than initial 13CH4 incorporation, with only about 5 to 10% of 13C-labeled PLFAs reflecting this process. Thus, 13C-labeled PLFA distributions determined at any time point during 13CH4 incubation can be used for chemotaxonomic assessments, although extended incubations are required to achieve optimum 13C labeling for methanotrophic biomass determinations.


1994 ◽  
Vol 10 (2) ◽  
pp. 219-228 ◽  
Author(s):  
A. A. Adu ◽  
A. R. Yeo ◽  
O. T. Okusanya

ABSTRACTThe effects of salinity upon the growth, photosynthesis, ion and water contents of a population of Dactyloctenium aegyptium originating from a saline site in Nigeria were investigated. Growth was unaffected by a salinity of 10% artificial sea water, but was reduced by one third in 20% and by two thirds in 30% artificial sea water respectively. Initial adjustment to salinity was due both to increases in the concentrations of sodium and potassium per unit dry weight and to reduced hydration, the latter being the more important at higher salinities. The increase in ion concentration in the cell sap balanced the salinity of the medium at 10% artificial sea water, but was excessive at higher concentrations of sea water. Net photosynthesis was unaffected by 10% artificial sea water but declined at higher salinities. The potassium content of the plants did not fall below 200–250 mM, and the sodium to potassium ratio did not exceed three, even at the highest salinities. Variation in the concentration of nutrients (potassium, nitrate and sulphate) in the medium in the presence of 25% artificial sea water had significant effects upon growth, but these were small in relation to the inhibitory effect of the salinity.The reduction in growth could not be attributed to lack of osmotic adjustment or to nutrient deficiency, and was probably due to ion toxicity within the leaves. The tolerance to reduced hydration, combined with the ability to germinate in saline conditions previously observed, could enable D. aegyptium to establish in a saline soil. The population did not exhibit any halophytic characteristics but did survive with a low growth rate at salinities up to 50% artificial sea water. It is concluded that the species was able to colonize the saline site because of its inherent adaptability, rather than the possession of an ecotype adapted to saline conditions.


1969 ◽  
Vol 15 (5) ◽  
pp. 389-398 ◽  
Author(s):  
K. Budd

The assimilation of 14C-bicarbonate under controlled conditions was examined in midlog-phase mycelium grown on dextrose as sole carbon source. Sustained assimilation depended on the presence of exogenous nitrogen and carbon sources. When these were provided, assimilation rates of 20–30 μmoles/hour per 100 mg dry weight were maintained for at least 4 hours. After the second hour, almost all of the assimilated bicarbonate-C entered the 80% ethanol-insoluble fraction. Amino acids, especially aspartic and glutamic, were the main destination of assimilated bicarbonate-C; nucleic acids and acids of the tricarboxylic acid cycle accounted for smaller amounts of this carbon. The apparent Km for overall assimilation was 1.4 – 2.2 × 10−4 M with respect to bicarbonate.Assimilation was inhibited by inhibitors of protein synthesis, especially actidione and p-fluorophenylalanine. Evidence was obtained for regulation of assimilation by its end products, and also by the carbon source on which the mycelium was grown. It is concluded that assimilation of bicarbonate or CO2 has an anaplerotic function during protein synthesis in this organism.


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