Optimization of Mixed-Cultivation Conditions of Methanotrophs from the Aged Refuse

2012 ◽  
Vol 433-440 ◽  
pp. 4746-4750
Author(s):  
Juan Mei ◽  
You Cai Zhao ◽  
Qun Su ◽  
Dan Han ◽  
Ren Hua Huang ◽  
...  

Methanotrophs-bearing liquid cultivated from the aged refuse has been proved to be effective for improving methane oxidation ability of landfill cover materials, and this is significant for CH4 emission control in landfill site. Optimization of mixed-cultivation conditions of methanotrophs from the aged refuse was studied in this paper. It was demonstrated that the best inoculums mode was using supernatant liquor of the aged refuse and nitrate minimal salt medium (NMS), and the lag phase of the growth was only 37 hours. The optimum growth of methanotrophs was observed at 28~35°C. Paraffin was attested to be useful for mixed methanotrophs cultivation and the highest methane oxidation rate reached 4mL/h with paraffin added.

2021 ◽  
Author(s):  
Oladipo Olaniyi

Abstract The goal of this present investigation was to mutagenize Bacillus subtilis with Ethyl Methyl Sulphonate (EMS), screen the mutants for cellulase production and evaluate the influence of different glucose concentrations on their cellulase production potentials. The wild type B. subtilis was treated with 20, 40, 60 and 80 µl of EMS and the mutants generated were screened for cellulase production in minimal salt medium containing carboxylmethylcellulose (CMC) as the carbon source. Quantitatively, cellulase activity and protein contents were determined by dinitrosalicylic acid and Lowry methods respectively. Seven mutants were developed from each of the EMS concentration bringing the total to twenty-eight from all the concentrations. Approximately 14 and 57% of the mutants developed from 40 and 60µl of EMS had higher cellulase activities than the wild type, while none of the mutants developed from 20 and 80 µl of EMS had better activities than the wild type. The supplementation of 0.2, 0.5, 1.0 and 1.5% glucose in enzyme production medium caused approximately 100, 14, 29 and 14% cellulase repression respectively in the mutants developed from 60µl EMS. Mutants MSSS02 and MSSS05 were considered as catabolite insensitive mutants because their cellulase production were enhanced in comparison to wild type.


2021 ◽  
Author(s):  
Asma Ben Salem ◽  
Hanene Chaabane ◽  
Tesnime Ghazouani ◽  
Pierluigi Caboni ◽  
Valentina Coroneo ◽  
...  

Abstract Important mineralization of 14C-chlorpyrifos was found in a Tunisian soil exposed repeatedly to this insecticide. A bacterial strain able to grow in minimal salt medium (MSM) supplemented with 25 mg L− 1 of chlorpyrifos was isolated from this soil. It was characterized as Serratia rubidaea strain ABS 10 using morphological and biochemical analyses, as well as 16S rRNA sequencing. In liquid culture S. rubidaea stain ABS 10 was able to almost entirely dissipate chlorpyrifos within 48 hours of incubation. Although, S. rubidaea strain ABS 10 was able to grow on MSM supplemented with chlorpyrifos and to dissipate it in liquid culture, it was not able to mineralize 14C-chlorpyrifos. Therefore, one can conclude that the dissipation capability of this bacteria might be attributed to its capacity to adsorb CHL. In both non-sterile and sterile soil inoculated with S. rubidaea strain ABS 10, chlorpyrifos was more rapidly dissipated than in respective controls.


Microbiology ◽  
2020 ◽  
Vol 89 (2) ◽  
pp. 182-191
Author(s):  
A. F. Sabrekov ◽  
M. V. Semenov ◽  
I. E. Terent’eva ◽  
Yu. V. Litti ◽  
D. V. Il’yasov ◽  
...  

2011 ◽  
Vol 61 (12) ◽  
pp. 2996-3002 ◽  
Author(s):  
Morio Ishikawa ◽  
Kazuyuki Nakajima ◽  
Shihomi Ishizaki ◽  
Kayo Kodama ◽  
Akiko Okamoto-Kainuma ◽  
...  

Two novel strains of marine lactic acid bacteria, isolated from decaying marine algae collected from a subtropical area of Japan, are described. The isolates, designated O24-2T and O25-2, were Gram-positive, non-sporulating and non-motile. They lacked catalase and quinones. Under anaerobic cultivation conditions, lactate was produced from glucose with the production of formate, acetate and ethanol in a molar ratio of approximately 2 : 1 : 1. Under aerobic cultivation conditions, acetate and lactate were produced from carbohydrates and related compounds. The isolates were slightly halophilic, highly halotolerant and alkaliphilic. They were able to grow in 0–17.0 % (w/v) NaCl, with optimum growth of strains O24-2T and O25-2 at 1.0–3.0 and 1.0–2.0 % (w/v) NaCl, respectively. Growth of strain O24-2T was observed at pH 7.5–9.5, with optimum growth at pH 8.0–8.5. Comparative 16S rRNA gene sequence analysis revealed that the isolates occupied a phylogenetic position within the genus Alkalibacterium, showing highest similarity (99.6 %) to Alkalibacterium putridalgicola T129-2-1T. Although sequence similarity was high, the DNA–DNA relatedness value between strain O24-2T and A. putridalgicola T129-2-1T was 27 %, indicating that they are members of distinct species. The DNA G+C contents of O24-2T and O25-2 were 43.7 and 44.4 mol%, respectively, and DNA–DNA relatedness between the isolates was 89 %. The cell-wall peptidoglycan was type A4β, Orn-d-Asp. The major cellular fatty acid components were C14 : 0, C16 : 0 and C16 : 1ω9c. Based on phenotypic characteristics and genetic distinctiveness, the isolates were classified as representatives of a novel species within the genus Alkalibacterium, for which the name Alkalibacterium subtropicum sp. nov. is proposed; the type strain is O24-2T ( = DSM 23664T = NBRC 107172T).


2004 ◽  
Vol 67 (6) ◽  
pp. 1243-1246 ◽  
Author(s):  
H.-C. WONG ◽  
C.-N. CHANG ◽  
M.-Y. CHEN

Vibrio parahaemolyticus is a ubiquitous gram-negative enteropathogenic bacterium. To evaluate the risk of stress-adapted V. parahaemolyticus cells in food, we investigated the survivability of starvation-adapted and starvation-low salinity–adapted cells of this pathogen in different media against different stresses. Logarithmically grown bacterial cells were starved at 25°C in a minimal salt medium with 0.5 or 3.0% NaCl for 24 h. Resistances against challenges of heat, acid, and freeze-thaw treatment exhibited by the starvation-adapted cells were similar to those exhibited by the starvation-low salinity–adapted cells but substantially higher than those of the unadapted control cells. The increased stress resistance of the adapted cells against freeze-thaw challenge was lower in tryptic soy broth than in the starving medium. Resistance of the adapted bacteria against heat and freeze-thaw treatment was completely eliminated in filter-sterilized oyster homogenate medium. Practically, these results help to assess the risk of stress-adapted V. parahaemolyticus in food.


2017 ◽  
Author(s):  
Ingeborg Bussmann ◽  
Steffen Hackbusch ◽  
Patrick Schaal ◽  
Antje Wichels

Abstract. The Lena River is one of the biggest Russian rivers draining into the Laptev Sea. Due to predicted increasing temperatures, the permafrost areas surrounding the Lena Delta will melt at increasing rates. With this melting, high amounts of methane will reach the waters of the Lena and the adjacent Laptev Sea. Methane oxidation by methanotrophic bacteria is the only biological way to reduce methane concentrations within the system. However, the polar estuary of the Lena River is a challenging environment for bacteria, with strong fluctuations in salinity and temperature. We determined the activity (tracer method) and the abundance (qPCR) of aerobic methanotrophic bacteria. We described the methanotrophic population with MISA; as well as the methane distribution (head space) and other abiotic parameters in the Lena Delta in September 2013. In riverine water (S < 5) we found a median methane concentration of 22 nM, in mixed water (5 < S < 20) the median methane concentration was 19 nM and in polar water (S > 20) a median 28 nM was observed. The Lena River was not the methane source for surface water, and bottom water methane concentrations were mainly influenced by the concentration in surface sediments. However, the methane oxidation rate in riverine and polar water was very similar (0.419 and 0.400 nM/d), but with a higher relative abundance of methanotrophs and a higher estimated diversity with respect to MISA OTUs in the rivine water as compared to polar water. The turnover times of methane ranged from 167 d in mixed water, 91 d in riverine water and only 36 d in polarwater. Also the environmental parameters influencing the methane oxidation rate and the methanotrophic population differed between the water masses. Thus we postulate a riverine methanotrophic population limited by sub-optimal temperatures and substrate concentrations and a polar methanotrophic population being well adapted to the cold and methane poor environment, but limited by the nitrogen content. The diffusive methane flux into the atmosphere ranged from 4–163 µmol m2 d−1 (median 24). For the total methane inventory of the investigated area, the diffusive methane flux was responsible for 8 % loss, compared to only 1 % of the methane consumed by the methanotrophic bacteria within the system.


2021 ◽  
Vol 13 (2) ◽  
pp. 641-653
Author(s):  
Madhusudhan S ◽  
S.K. Jalali ◽  
Sibi G

The cotton bollworm Helicoverpa armigera occurs as a major pest in many economically important crops, including cotton, pigeon pea, chickpea, pea, cowpea, sunflower, tomato, sorghum, pearl millet and other crops. Intestinal microorganisms play important role in the degradation of diet components of insects. In order to know the role of gut bacteria in insecticide resistance five   insecticides Chlorpyriphos (20% EC), Cypermethrin (25% EC), Malathion (50% EC), Quinalphos (25% EC), Triazophos (40% EC), were selected for the insecticide degradation studies. All the bacterial isolates from the gut of lab and field populations of H. armigera were identified using 16S rRNA gene-based identification and tested for their growth on minimal salt medium (MSM) along with the selected insecticides. A total of 11 bacterial isolates were tested and among them, isolate CL4 (Rhodococcus sp.) was found to grow on minimal salt medium (MSM) and with chlorpyriphos and isolate CL2 (Enterococcus casseliflavus) was able to grow in MSM with chloropyriphos (C22H19Cl2NO3) and malathion (C10H19O6PS2) and no growth was seen in MSM without insecticide (control).  Gas Chromatography analysis of the positive bacterial isolate cultures in MSM showed that the isolate CL4 (Rhodococcus sp.) was able to utilize 43.9% of chlorpyriphos and isolate CL2 (E.casseliflavus) was able to utilize 26% of chlorpyriphos and 57.1% of malathion in MSM broth cultures with comparison with the respective control cultures. Findings of the current work suggested that gut bacteria in the field populations of H. armigera plays a role in insecticide resistance


2020 ◽  
Vol 13 (1) ◽  
pp. 95-104
Author(s):  
Tiara Elsita Masni ◽  
Tetty Marta Linda ◽  
Bernadeta Leni Fibriarti

AbstrakFenol adalah senyawa organik yang bersifat toksik dan larut dalam air, sehingga mudah menimbulkan pencemaran pada perairan dan menurunkan kualitas air. Penelitian ini bertujuan untuk melihat potensi tiga isolat aktinomisetes asal tanah gambut Riau dalam Minimal Salt Medium yang mengandung fenol pada konsentrasi 0 ppm, 200 ppm, 400 ppm, dan 600 ppm serta mengetahui kemampuan aktinomisetes dalam mendegradasi fenol pada konsentrasi 600 ppm menggunakan metode folin ciocalteau. Potensi pertumbuhan isolat L121, L18, L11 menunjukkan total populasi tidak berbeda nyata dengan penambahan 400 ppm dan 600 ppm fenol, tetapi berbeda nyata terhadap 0 ppm dan 200 ppm fenol. Potensi pertumbuhan tertinggi terdapat pada isolat L121 dan terendah pada isolat L11. Kemampuan degradasi  fenol oleh  masing-masing isolat adalah  L121 sebesar 570,80 ppm (95%),  L18 sebesar 218,85 ppm (36%)  dan L11 sebesar  97,21 ppm (16%)  dari konsentrasi fenol awal 600 ppm pada Minimal Salt Medium. Isolat aktinomisetes ini berpotensi dikembangkan untuk penanggulangan pencemaran di lingkungan.Abstract Phenol is an organic compound is toxic and easily soluble in water so easy to cause pollution in a waters such as water quality degradation. The aim of this research is to see the potential of three isolates of actinomycetes from Riau peat soil in Minimal Salt Medium containing phenol concentration 0 ppm, 200 ppm, 400 ppm and 600 ppm and to know the ability of actinomycetes in degradation of phenol at the concentration of 600 ppm using folin ciocalteu. The growth potential of L121, L18, L11 isolates showed the total population was not significantly different with the addition of 400 ppm and 600 ppm of phenol but significantly different from 0 ppm and 200 ppm of phenol. The highest growth potential was found in L121 isolate and lowest in L11 isolate. The degradation ability of phenols by each isolate was L121 570.80 ppm (95%), L18 218.85 ppm (36%) and L11 was able to degrade phenol 97.21 ppm (16%) from the initial phenol concentration of 600 ppm at Minimum Salt Medium.These actinomycetes have the potential to be developed for the overcome of pollution in the environment.


1960 ◽  
Vol 27 (2) ◽  
pp. 221-234 ◽  
Author(s):  
Constance Higginbottom ◽  
Margaret M. Taylor

SummaryThe sterilization of homogenized milk at 115·5°C for 15 min in bottles having a partial vacuum in the headspace produced conditions inhibitory to the growth from very small numbers of spores ofBacillus subtilis, B. licheniformis, B. cereusandB. breviswhen compared with growth in the same milk sterilized in open bottles.B. circulansdiffered from the other strains tested in showing greater inhibition in milk sterilized in open bottles than in milk sterilized under partial vacuum.The extent of the inhibition became less as the size of the inoculum was increased. It became less also as the temperature of incubation approached the optimum growth temperature of the bacillus, and was influenced by the strain of the bacillus and the source of the milk but not by the degree of heat treatment within the range 107–117·5°C for 15 min. Inhibition was manifested by a prolongation of the lag phase, and in addition with some strains inhibition of spore germination could be demonstrated.Spore formation following vegetative growth occurred more readily in milk sterilized in open than in evacuated bottles.Milks sterilized under partial vacuum frequently failed to show any growth from small inocula in 30 days at 22°C although growth occurred readily in milk sterilized in open bottles.


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