Physiology ofAspergillus nigerin oxygen-limited continuous cultures: Influence of aeration, carbon source concentration and dilution rate

2009 ◽  
Vol 103 (5) ◽  
pp. 956-965 ◽  
Author(s):  
A. Diano ◽  
J. Peeters ◽  
J. Dynesen ◽  
J. Nielsen
Keyword(s):  
Carbon Source ◽  
Dilution Rate ◽  
Continuous Cultures ◽  
Source Concentration

Influence of Carbon Source Concentration on Characterization of Boron-Doped Diamond Electrodes

2011 ◽  
Vol 204-210 ◽  
pp. 1691-1696
Author(s):  
Yu Qiang Chen ◽  
Jiang Wei Lv ◽  
Hong Wei Jiang ◽  
Hong Yan Peng ◽  
Yu Jie Feng ◽  
...  
Keyword(s):  
Carbon Source ◽  
Phenol Degradation ◽  
Chemical Vapor ◽  
Crystalline Lattice ◽  
Boron Doped Diamond ◽  
Graphite Phase ◽  
Substitutional Site ◽  
Boron Doped ◽  
Source Concentration

A set of boron-doped diamond (BDD) electrodes were deposited on silicon substrates by direct current plasma chemical vapor deposition (DC-PCVD) system using different carbon source concentrations. The influence of carbon source concentration on characterization of BDD electrodes was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and phenol degradation. It was found that BDD films with different carbon source concentrations were polycrystalline films with (111) dominant orientation. The films grew well when carbon source concentration was less than 2.5%, while graphite phase began to form when carbon source concentration was increased to 3%. Boron atoms were located at the substitutional site or interstitial sites in the crystalline lattice of diamond films, and didn’t damage the structure of diamond crystal. Within 4 h, 100 mg/L phenol solution in 80 ml could be oxidized by all the electrodes with removal efficiency higher than 90%.

Transient responses of Wickerhamia sp. yeast continuous cultures to qualitative changes in carbon source supply: induction and catabolite repression of α-amylase synthesis

2018 ◽  
Vol 68 (10) ◽  
pp. 625-635
Author(s):  
Griselda Ma. Chávez-Camarillo ◽  
Uriel Mauricio Santiago-Flores ◽  
Armando Mena-Vivanco ◽  
Liliana Morales-Barrera ◽  
Elias Cortés-Acosta ◽  
...  
Keyword(s):  
Carbon Source ◽  
Catabolite Repression ◽  
Transient Responses ◽  
Continuous Cultures ◽  
Qualitative Changes

scholarly journals Regulation of Cellulase Synthesis in Batch and Continuous Cultures of Clostridium thermocellum

2005 ◽  
Vol 187 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Zhang Percival Yi-Heng ◽  
Lee R. Lynd
Keyword(s):  
Dilution Rate ◽  
Substrate Concentration ◽  
Catabolite Repression ◽  
Clostridium Thermocellum ◽  
Peptide Sequence ◽  
Enzyme Linked Immunosorbent Assay ◽  
Limited Growth ◽  
Continuous Cultures ◽  
Batch Cultures ◽  
Batch Growth

ABSTRACT Regulation of cell-specific cellulase synthesis (expressed in milligrams of cellulase per gram [dry weight] of cells) by Clostridium thermocellum was investigated using an enzyme-linked immunosorbent assay protocol based on antibody raised against a peptide sequence from the scaffoldin protein of the cellulosome (Zhang and Lynd, Anal. Chem. 75:219-227, 2003). The cellulase synthesis in Avicel-grown batch cultures was ninefold greater than that in cellobiose-grown batch cultures. In substrate-limited continuous cultures, however, the cellulase synthesis with Avicel-grown cultures was 1.3- to 2.4-fold greater than that in cellobiose-grown cultures, depending on the dilution rate. The differences between the cellulase yields observed during carbon-limited growth on cellulose and the cellulase yields observed during carbon-limited growth on cellobiose at the same dilution rate suggest that hydrolysis products other than cellobiose affect cellulase synthesis during growth on cellulose and/or that the presence of insoluble cellulose triggers an increase in cellulase synthesis. Continuous cellobiose-grown cultures maintained either at high dilution rates or with a high feed substrate concentration exhibited decreased cellulase synthesis; there was a large (sevenfold) decrease between 0 and 0.2 g of cellobiose per liter, and there was a much more gradual further decrease for cellobiose concentrations >0.2 g/liter. Several factors suggest that cellulase synthesis in C. thermocellum is regulated by catabolite repression. These factors include: (i) substantially higher cellulase yields observed during batch growth on Avicel than during batch growth on cellobiose, (ii) a strong negative correlation between the cellobiose concentration and the cellulase yield in continuous cultures with varied dilution rates at a constant feed substrate concentration and also with varied feed substrate concentrations at a constant dilution rate, and (iii) the presence of sequences corresponding to key elements of catabolite repression systems in the C. thermocellum genome.

Extracellular Xylanase Production by Two Thermophilic Alkali-Tolerant Bacillus Strains in Batch and Continuous Cultures

2000 ◽  
Vol 55 (1-2) ◽  
pp. 66-69 ◽  
Author(s):  
Elka I. Emanuilova ◽  
Plamen L. Dimitrov ◽  
Rossica D. Mandeva ◽  
Margarita S. Kambourova ◽  
Stefan A. Engibarov
Keyword(s):  
Dilution Rate ◽  
Enzyme Synthesis ◽  
Bacillus Sp ◽  
Continuous Cultures ◽  
Xylanase Production ◽  
Batch Cultures ◽  
Bacillus Strains ◽  
Oat Spelt

Abstract Xylanase production of newly isolated thermophilic alkali-tolerant Bacillus sp. strain SP and strain BC was investigated in batch and continuous cultures. Enzyme synthesis was inducible with both strains and was observed only in xylan-containing media. Xylan from oat spelt is a better inducer than xylan from birch for strain Bacillus sp. BC while such difference was not observed for strain SP Compared with batch cultures xylanase production of both strains increased about two times and its rate became more than four times faster in continuous cultures at a dilution rate of 0.2 h-1.

Research on microbial lipid production from potato starch wastewater as culture medium by Lipomyces starkeyi

2013 ◽  
Vol 67 (8) ◽  
pp. 1802-1808 ◽  
Author(s):  
Jun-Xian Liu ◽  
Qin-Yan Yue ◽  
Bao-Yu Gao ◽  
Yan Wang ◽  
Qian Li ◽  
...  
Keyword(s):  
Cell Growth ◽  
Carbon Source ◽  
Nitrogen Source ◽  
Culture Medium ◽  
Potato Starch ◽  
Inoculum Size ◽  
Microbial Lipid ◽  
Lipomyces Starkeyi ◽  
Starch Wastewater ◽  
Source Concentration

In this paper, potato starch wastewater as culture medium was treated by the oleaginous yeast Lipomyces starkeyi to biosynthesize microbial lipid. The result indicated that carbon source types, carbon source concentration, nitrogen source types, nitrogen source concentration, inoculum size, and cultivation time all had a significant effect on cell growth and microbial lipid accumulation in batch cultures. A measure of 120 g/L of glucose concentration, 3.0 g/L of (NH4)2SO4 concentration, 10% inoculum size, and incubation time 96 h cultivated in a shaking flask at 30 °C were found to be the optimal conditions not only for cell growth but also for lipid synthesis. Under this condition, the cellular biomass and lipid content could reach 2.59 g/L and 8.88%, respectively. This work provides a new method for effective utilization of potato starch wastewater, which has particular social and economic benefits for yeast treatment technology.

scholarly journals Cultivation of the Oil-Producing Yeast Microorganism Rhodotorula mucilaginosa for Sustainable Production of Bio-Oil Energy

2021 ◽  
Author(s):  
Shu-Yao Tsai ◽  
Hsuan-Ti Yu ◽  
Chun-Ping Lin
Keyword(s):  
Carbon Source ◽  
Large Scale ◽  
Carbon Sources ◽  
Yeast Cells ◽  
Rhodotorula Mucilaginosa ◽  
Bio Oil ◽  
Heat Method ◽  
Oil Source ◽  
Accumulation Of Lipids ◽  
Source Concentration

This study was focused on the development of oil-producing microorganisms to generate lipids. The yeast Rhodotorula mucilaginosa (R. mucilaginosa) was selected for liquid-state cultivation, and the conditions for growth of the yeast cells were assessed. Additionally, the relationships between different nutrient elements and the growth of R. mucilaginosa were explored. The lipid accumulation of R. mucilaginosa is increased under nitrogen-restricted conditions. As the concentration of the carbon source increases, the accumulation of lipids is increased. However, if the carbon source concentration is further increased, the growth of yeast is inhibited. From a large-scale liquid fermentation culture with a fixed inoculation amount of 5%, and from a batch of culture experiments, it was determined that a suitable oil-producing culture was obtained on the 6th day, and the optimum conditions involved a carbon source concentration of 60 g/L, a nitrogen source concentration of 0.5 g/L, and a KH2PO4 concentration of 7.0 g/L. After utilizing different carbon sources in this study, it was found that glucose was the carbon source most conducive to the accumulation of R. mucilaginosa lipids. In addition, the extraction method and solvent for the extraction of R. mucilaginosa lipids were chosen. The acid-heat method using the green organic solvent ethyl acetate exhibited the best performance for extraction of yeast lipids under environmentally friendly and safe conditions. The analysis of lipids showed that the fatty acids obtained primarily contained C16:0, C18:1 and C18:2, and especially C18:1 (41%) lipids, indicating that R. mucilaginosa lipids are a good bio-oil source for the production of biodiesel.

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