Theoretical maximum and observed product yields associated with curdlan production by Alcaligenes faecalis

1983 ◽  
Vol 29 (10) ◽  
pp. 1270-1276 ◽  
Author(s):  
K. R. Phillips ◽  
H. G. Lawford
Keyword(s):  
Process Improvement ◽  
Conversion Efficiency ◽  
Nitrogen Limitation ◽  
Glucose Consumption ◽  
Product Yield ◽  
Alcaligenes Faecalis ◽  
Carbon Limitation ◽  
Average Value ◽  
Theoretical Maximum ◽  
Curdlan Production

As a guide to both strain and process improvement and based on certain assumptions concerning both glucose and energy metabolism of the process organism, Alcaligenes faecalis var. myxogenes, the theoretical "maximum" carbon (glucose) substrate to product conversion efficiency (i.e., product yield) has been estimated for "curdlan-type" β(1 → 3)-glucan exopolysaccharide production in batch fermentations. Under nitrogen limitation, which promotes curdlan biosynthesis (μ = 0), the rate of glucose consumption for cellular maintenance energy (grams of glucose per gram of cells per hour) was approximately five times higher than under carbon limitation. The decrease in the theoretical "maximum" curdlan conversion efficiency of 74% to the average value of 50–56% was due primarily to the high maintenance coefficient of the nitrogen-starved culture.

Production of curdlan-type polysaccharide by Alcaligenes faecalis in batch and continuous culture

1983 ◽  
Vol 29 (10) ◽  
pp. 1331-1338 ◽  
Author(s):  
K. Railton Phillips ◽  
J. Pik ◽  
H. G. Lawford ◽  
B. Lavers ◽  
A. Kligerman ◽  
...  
Keyword(s):  
Chemostat Culture ◽  
Product Yield ◽  
Alcaligenes Faecalis ◽  
Single Stage ◽  
Specific Rate ◽  
Continuous Cultures ◽  
Batch Cultures ◽  
Curdlan Production ◽  
Spontaneous Variant

The biosynthesis of a thermogelable, extracellular homo-β-(1 → 3)-glucan called "curdlan," has been studied in batch and continuous cultures of Alcaligenes faecalis var. myxogenes. Curdlan production is associated with the poststationary phase of a nitrogen-depleted, aerobic batch culture. Exopolymer is not detected in single-stage, carbon-limited continuous cultures but curdlan can be isolated from the effluent of a nitrogen-limited chemostat operating at a dilution rate (D) of < 0.1 h−1. A spontaneous variant of strain ATCC 21680 was isolated and found to be compatible with long-term, nitrogen-limited chemostat culture. The specific rate of curdlan production is approximately four times higher in poststationary batch cultures than in single-stage continuous fermentations. The product yield (Yp/s) associated with batch processing (nongrowing cultures) is approximately 0.5 g curdlan/g glucose, with CO2 being the only detectable by-product.

Inkjet printing of CH3NH3PbI3 on a mesoscopic TiO2 film for highly efficient perovskite solar cells

2015 ◽  
Vol 3 (17) ◽  
pp. 9092-9097 ◽  
Author(s):  
Shao-Gang Li ◽  
Ke-Jian Jiang ◽  
Mei-Ju Su ◽  
Xue-Ping Cui ◽  
Jin-Hua Huang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Tio2 Film ◽  
Inkjet Printing ◽  
Power Conversion ◽  
Perovskite Solar Cells ◽  
Average Value ◽  
Structure And Morphology ◽  
Light Absorber

CH3NH3PbI3 is deposited as a light absorber on a mesoporous TiO2 film and the structure and morphology are investigated at different table temperatures and with various amounts of added CH3NH3Cl. The optimized device exhibits the highest power conversion efficiency of 12.3% with an average value of 11.2%.

scholarly journals Bioderivatization as a concept for renewable production of chemicals that are toxic or poorly soluble in the liquid phase

2020 ◽  
Vol 117 (3) ◽  
pp. 1404-1413 ◽  
Author(s):  
Pachara Sattayawat ◽  
Ian Sofian Yunus ◽  
Patrik R. Jones
Keyword(s):  
Liquid Phase ◽  
Glucose Consumption ◽  
Product Yield ◽  
Cellular Growth ◽  
Product Titer ◽  
Product Removal ◽  
Enhanced Solubility ◽  
Poorly Soluble ◽  
Reduced Toxicity ◽  
Positive Effect

Bio-based production technologies may complement or replace petroleum-based production of chemicals, but they face a number of technical challenges, including product toxicity and/or water insolubility. Plants and microorganisms naturally biosynthesize chemicals that often are converted into derivatives with reduced toxicity or enhanced solubility. Inspired by this principle, we propose a bioderivatization strategy for biotechnological chemicals production, defined as purposeful biochemical derivatization of intended target molecules. As proof of principle, the effects of hydrophobic (e.g., esterification) and hydrophilic (e.g., glycosylation) bioderivatization strategies on the biosynthesis of a relatively toxic and poorly soluble chemical, 1-octanol, were evaluated in Escherichia coli and Synechocystis sp. PCC 6803. The 1-octanol pathway was first optimized to reach product titers at which the host displayed symptoms of toxicity. Solvent overlay used to capture volatile products partially masked product toxicity. Regardless of whether solvent overlay was used, most strains with bioderivatization had a higher molar product titer and product yield, as well as improved cellular growth and glucose consumption, compared with strains without bioderivatization. The positive effect on bioproduction was observed with both the hydrophobic and hydrophilic strategies. Interestingly, in several combinations of genotype/induction strength, bioderivatization had a positive effect on productivity without any apparent effect on growth. We attribute this to enhanced product solubility in the aqueous or solvent fraction of the bioreactor liquid phase (depending on the derivative and medium used), with consequent enhanced product removal. Overall, under most conditions, a benefit of bioproduction was observed, and the bioderivatization strategy could be considered for other similar chemicals as well.

Kinetic analysis of curdlan production by Alcaligenes faecalis with maltose, sucrose, glucose and fructose as carbon sources

2018 ◽  
Vol 259 ◽  
pp. 319-324 ◽  
Author(s):  
Qin Zhang ◽  
Jingyun Sun ◽  
Zejian Wang ◽  
Haifeng Hang ◽  
Wei Zhao ◽  
...  
Keyword(s):  
Kinetic Analysis ◽  
Carbon Sources ◽  
Alcaligenes Faecalis ◽  
Curdlan Production

scholarly journals Intercropping legumes and cereals increases phosphorus use efficiency; a meta-analysis

2020 ◽  
Author(s):  
Xiaoyan Tang ◽  
Chaochun Zhang ◽  
Yang Yu ◽  
Jianbo Shen ◽  
Wopke van der Werf ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Crop Yields ◽  
Meta Analysis ◽  
Species Traits ◽  
P Uptake ◽  
Phosphorus Use Efficiency ◽  
Average Value ◽  
Land Use Efficiency ◽  
P Fertilizer ◽  
Use Efficiency

Abstract Aims Intercropping cereals with legumes may achieve high crop yields at reduced input levels. Several studies have indicated that intercropping increases phosphorus use efficiency but no overarching analysis exists on the role of species traits and input levels. Here we synthesize the available information on P use efficiency in cereal/legume intercropping. Methods Global data on yields, P uptake and nutrient input in cereal/legume mixtures were extracted from the literature and statistically analyzed. Co-variables explaining P uptake efficiency and yield were considered. Results P uptake was substantially increased with an average value of LERP, the land equivalent ratio for P uptake, of 1.24, and an average NEP (observed P uptake minus expected P uptake) of 3.67 kg P ha−1. The conversion efficiency of P uptake to biomass decreased with P uptake and was lower in intercrops than in sole crops but the conversion efficiency to yield was not affected by intercropping. The P fertilizer requirement was 21% lower in intercrops than in sole crops for the same yields. Conclusions Substantial improvements in land use efficiency and P uptake are obtained by cereal/legume intercropping. Cereal/legume intercropping has therefore potential to increase P fertilizer use efficiency in agriculture.

scholarly journals Carbon Limitation Induces ςS-Dependent Gene Expression in Pseudomonas fluorescens in Soil

2001 ◽  
Vol 67 (8) ◽  
pp. 3363-3370 ◽  
Author(s):  
Birgit Koch ◽  
Jakob Worm ◽  
Linda E. Jensen ◽  
Ole Højberg ◽  
Ole Nybroe
Keyword(s):  
Single Cell ◽  
Pseudomonas Fluorescens ◽  
Nitrogen Limitation ◽  
Bulk Soil ◽  
Barley Straw ◽  
Staining Procedure ◽  
Carbon Limitation ◽  
Galactosidase Activity ◽  
Carbon Availability ◽  
Carbon And Nitrogen

ABSTRACT Recent studies employing reporter gene technology indicate that the availabilities of the major nutrients nitrogen, phosphate, and iron toPseudomonas are not severely limited in bulk soil. Indirect evidence has pointed to carbon limitation as a severe nutritional stress in this environment. We show that a plasmid (pGM115)-borne transcriptional fusion between the ςS-dependent Escherichia coli promoterP fic and lacZfunctions as a reliable reporter for carbon availability inPseudomonas fluorescens. When P. fluorescens strain DF57(pGM115) was introduced into bulk soil, carbon-limiting conditions were indicated by citrate-repressible induction of β-galactosidase activity. To address carbon availability at the single-cell level, we developed an immunofluorescence double-staining procedure for individual DF57 cells expressing β-galactosidase from P fic . Changes in cell size and expression of β-galactosidase were analyzed by flow cytometry. Cells extracted from soil microcosms reduced their size less than carbon-starved cells in pure culture and showed an increased tendency to aggregate. The single-cell analysis revealed that for cells residing in soil, the expression of β-galactosidase became heterogeneous and only a DF57 subpopulation appeared to be carbon limited. In soil amended with barley straw, limited nitrogen availability has been determined by use of the bioluminescent reporter strain P. fluorescensDF57-N3. We used strain DF57-N3(pGM115) as a double reporter for carbon and nitrogen limitation that allowed us to study the dynamics of carbon and nitrogen availabilities in more detail. In straw-amended soil β-galactosidase activity remained low, while nitrogen limitation-dependent bioluminescence appeared after a few days. Hence, nitrogen became limited under conditions where carbon resources were not completely exhausted.

scholarly journals Comparison of measured performance and theoretical limits of gaas laser power converters under monochromatic light

2017 ◽  
Vol 30 (1) ◽  
pp. 93-106 ◽  
Author(s):  
Rok Kimovec ◽  
Marko Topic
Keyword(s):  
Conversion Efficiency ◽  
Laser Power ◽  
Power Converters ◽  
Incident Light ◽  
Monochromatic Light ◽  
Detailed Balance ◽  
Limit Values ◽  
Central Wavelength ◽  
Theoretical Maximum ◽  
Gaas Laser

Evaluation of GaAs laser power converters (LPC) is reported in light of theoretical maximum limits calculated with detailed balance method as proposed by Shockley and Queisser (SQ). Calculations were done for three different theoretical structures of LPCs homogeneously illuminated by monochromatic light. Effects of LPC thickness, central wavelength of a monochromatic light source and various irradiance levels are discussed. Reflection of incident light from the interface between air and GaAs is calculated and countermeasures in the form of single and double layer anti reflection coatings are theoretically studied. Measurements of single junction, single segment GaAs LPC illuminated by monochromatic light with central wavelength ?0 = 808 nm are presented and compared with the theoretical maximum values. The conversion efficiency ?meas = 54,4 % was measured for GaAs LPC illuminated with power density of monochromatic light pillum = 14,3 W/cm2 at the temperature of the LPC casing T = 302 K. For the same parameters conversion efficiency ?SQ = 76,6 % was calculated resulting in utilization ratio ?meas/?SQ=0,71. Measured Jsc and Voc achieve 88,5 % and 89,2 % of theoretically calculated SQ limit values.

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