scholarly journals Design of a Cascade Observer for a Model of Bacterial Batch Culture with Nutrient Recycling

Author(s):  
Miled El ◽  
Alain Rapaport
2000 ◽  
Vol 42 (12) ◽  
pp. 149-154 ◽  
Author(s):  
M. Okada ◽  
H. Morinaga ◽  
W. Nishijima

Effects of PAC on bacterial activity were evaluated by sequencing batch cultures (20 hours each) of E.coli K-12 on synthetic medium containing glucose as a sole carbon source. Four suspended sequencing batch culture systems were operated; CP: cultures supplemented with PAC, CR: cultures with removal of metabolites by PAC at the end of each batch culture, CD: cultures supplemented with PAC in dialysis tubing to separate from E.coli, and CC: cultures without PAC (control). The supernatant of each batch culture was filtered through a membrane filter (0.2 μm) and was mixed with the same volume of fresh medium to be used as the medium for the next batch culture. The sequencing batch cultures were repeated three times for all the systems. The bacterial growth in CC was inhibited with the increase in the number of batch cultures. Although a significant amount of metabolites was accumulated in the 3rd batch culture of CC, little accumulation was noted in the 3rd batch culture of CP. No growth inhibition was noted in CP for all the batch cultures. The little differences in the bacterial yield and metabolite accumulation between CR and CD suggested that adsorption/desorption of metabolites with PAC did not play a major role in bacterial growth. PAC addition may partly stimulate the growth by the removal of growth inhibiting metabolites. However, the fact that CP showed higher yield than CR and CD indicated that the contact between bacteria and PAC plays a significant role in the growth of bacteria.


2017 ◽  
Vol 4 (2) ◽  
Author(s):  
SANJEEV KUMAR ◽  
SHIVANI . ◽  
S. K. SAMAL ◽  
S. K. DWIVEDI ◽  
MANIBHUSHAN .

Integration of different components viz. livestock, fishery, horticulture, mushroom etc. along with field crops not only enhanced productivity but by-products (waste) of one component act as input for another component through resource recycling within the system. Six integrated farming systems models with suitable combinations of Crop, vegetables, fruit trees, fish, livestock, mushroom etc. were made and evaluated at the experimental farm of ICAR Research Complex for Eastern Region, Patna during 2012-16 for harness maximum income, nutrient recycling and employment. Among six combinations, crop + fish + duck + goat resulted as most profitable combination in terms of productivity (RGEY- 22.2t), net income (Rs. 2,15,900/ha), additional employment (170 days/year) with income sustainability index (ISI) by 90.2. Upon nutrient recycling prepared from different wastes from the system Crop + fish + duck + goat combination added N (56.5 kg), P (39.6 kg) and K (42.7 kg) into the soil and reduced the cost of cultivation by 24 percent and was followed by crop + fish + goat combination. Crops grown under IFS mode with different types of manures produced 31 percent higher yield over conventional rice- wheat system. The contribution of crops towards the system productivity ranged from 36.4 to 56.2 %, while fish ranged from 22.0-33.5 %; for goat 25.4-32.9 %; for poultry 38.7 %; for duck 22.0-29.0 %; for cattle 32.2% and for mushroom 10.3 %.


2021 ◽  
Vol 289 ◽  
pp. 125708
Author(s):  
Sérgio Siqueira Amorim Junior ◽  
Valéria Sun Hwa Mazucato ◽  
Beatriz dos Santos Machado ◽  
Denilson de Oliveira Guilherme ◽  
Reginaldo Brito da Costa ◽  
...  

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Karin Holmfeldt ◽  
Emelie Nilsson ◽  
Domenico Simone ◽  
Margarita Lopez-Fernandez ◽  
Xiaofen Wu ◽  
...  

AbstractThe deep biosphere contains members from all three domains of life along with viruses. Here we investigate the deep terrestrial virosphere by sequencing community nucleic acids from three groundwaters of contrasting chemistries, origins, and ages. These viromes constitute a highly unique community compared to other environmental viromes and sequenced viral isolates. Viral host prediction suggests that many of the viruses are associated with Firmicutes and Patescibacteria, a superphylum lacking previously described active viruses. RNA transcript-based activity implies viral predation in the shallower marine water-fed groundwater, while the deeper and more oligotrophic waters appear to be in ‘metabolic standby’. Viral encoded antibiotic production and resistance systems suggest competition and antagonistic interactions. The data demonstrate a viral community with a wide range of predicted hosts that mediates nutrient recycling to support a higher microbial turnover than previously anticipated. This suggests the presence of ‘kill-the-winner’ oscillations creating slow motion ‘boom and burst’ cycles.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Rianne C. Prins ◽  
Sonja Billerbeck

Abstract Background Fungi are premier hosts for the high-yield secretion of proteins for biomedical and industrial applications. The stability and activity of these secreted proteins is often dependent on the culture pH. As yeast acidifies the commonly used synthetic complete drop-out (SD) media that contains ammonium sulfate, the pH of the media needs to be buffered in order to maintain a desired extracellular pH during biomass production. At the same time, many buffering agents affect growth at the concentrations needed to support a stable pH. Although the standard for biotechnological research and development is shaken batch cultures or microtiter plate cultures that cannot be easily automatically pH-adjusted during growth, there is no comparative study that evaluates the buffering capacity and growth effects of different media types across pH-values in order to develop a pH-stable batch culture system. Results We systematically test the buffering capacity and growth effects of a citrate-phosphate buffer (CPB) from acidic to neutral pH across different media types. These media types differ in their nitrogen source (ammonium sulfate, urea or both). We find that the widely used synthetic drop-out media that uses ammonium sulfate as nitrogen source can only be effectively buffered at buffer concentrations that also affect growth. At lower concentrations, yeast biomass production still acidifies the media. When replacing the ammonium sulfate with urea, the media alkalizes. We then develop a medium combining ammonium sulfate and urea which can be buffered at low CPB concentrations that do not affect growth. In addition, we show that a buffer based on Tris/HCl is not effective in maintaining any of our media types at neutral pH even at relatively high concentrations. Conclusion Here we show that the buffering of yeast batch cultures is not straight-forward and addition of a buffering agent to set a desired starting pH does not guarantee pH-maintenance during growth. In response, we present a buffered media system based on an ammonium sulfate/urea medium that enables relatively stable pH-maintenance across a wide pH-range without affecting growth. This buffering system is useful for protein-secretion-screenings, antifungal activity assays, as well as for other pH-dependent basic biology or biotechnology projects.


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