scholarly journals Production of palmitoleic acid by oleaginous yeast Scheffersomyces segobiensis DSM 27193 using systematic dissolved oxygen regulation strategy

2021 ◽  
Author(s):  
Xinhai Zhou ◽  
Dawei Zhou ◽  
Xinhui Bao ◽  
Jie Zhou ◽  
Fengxue Xin ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Palmitoleic Acid ◽  
Oleaginous Yeast ◽  
Lipid Production ◽  
Biomass Concentration ◽  
Aeration Rate ◽  
Agitation Speed ◽  
Intracellular Lipid ◽  
Transcription Analysis ◽  
Ethanol Formation

Abstract Background: Recently, a newly isolated oleaginous yeast strain Scheffersomyces segobiensis DSM 27193 was identified with the capability of accumulating high contents of palmitoleic acid (POA) in its intracellular lipid (13.8%). However, high amounts of ethanol as the main by-product were also produced in this system. To eliminate ethanol formation and to further improve POA production, process optimization focused on dissolved oxygen (DO) regulation was conducted in this study.Results: As a result, agitation control was found to be highly beneficial for cell growth and lipid production. When keeping pO2>40% through dynamic agitation control, significant improvements toward lipid (70.12% increase) and POA (1.44 fold) production have been obtained, and the accumulation of ethanol was decreased to 2.3 g/L. While increasing the aeration rate to 2 vvm, no significant decrease has been found in ethanol accumulation. Further application of a two-stage agitation regulation (600 rpm in the first 48 h fermentation then adjusted the agitation speed to 1000 rpm) gave 10.23 g/L of lipid (50% increase) with 2.02 g/L of POA (1.15 fold) production. At last, under the best condition of 1000 rpm of agitation and 1 vvm of aeration, no ethanol was detected during the whole fermentation process, while a dry biomass concentration of 44.8 g/L with 13.43 g/L of lipid and 2.93 g/L of POA was achieved. Transcription analysis revealed that ethanol synthetic pathway was down regulated under the condition of high agitation, while the expression of the key enzymes responsible for lipid and POA accumulation were enhanced.Conclusion: This study introduces the oleaginous yeast chassis S. segobiensis DSM 27193 and an effective pO2 regulation strategy for efficient biological production of POA.

scholarly journals Optimization of Aeration and Agitation Rate for Lipid and Gamma Linolenic Acid Production byCunninghamella bainieri2A1 in Submerged Fermentation Using Response Surface Methodology

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Normah Saad ◽  
Peyman Abdeshahian ◽  
Mohd Sahaid Kalil ◽  
Wan Mohtar Wan Yusoff ◽  
Aidil Abdul Hamid
Keyword(s):  
Response Surface Methodology ◽  
Production Process ◽  
Response Surface ◽  
Linolenic Acid ◽  
Lipid Production ◽  
Aeration Rate ◽  
Agitation Speed ◽  
Agitation Rate ◽  
Optimum Conditions ◽  
Gamma Linolenic Acid

The locally isolated filamentous fungusCunninghamella bainieri2A1 was cultivated in a 5 L bioreactor to produce lipid and gamma-linolenic acid (GLA). The optimization was carried out using response surface methodology based on a central composite design. A statistical model, second-order polynomial model, was adjusted to the experimental data to evaluate the effect of key operating variables, including aeration rate and agitation speed on lipid production. Process analysis showed that linear and quadratic effect of agitation intensity significantly influenced lipid production process (P<0.01). The quadratic model also indicated that the interaction between aeration rate and agitation speed had a highly significant effect on lipid production (P<0.01). Experimental results showed that a lipid content of 38.71% was produced in optimum conditions using an airflow rate and agitation speed of 0.32 vvm and 599 rpm, respectively. Similar results revealed that 0.058 (g/g) gamma-linolenic acid was produced in optimum conditions where 1.0 vvm aeration rate and 441.45 rpm agitation rate were used. The regression model confirmed that aeration and agitation were of prime importance for optimum production of lipid in the bioreactor.

scholarly journals Influence of Sparger Type and Regime of Fluid on Biomass and Lipid Productivity of Chlorella vulgaris Culture in a Pilot Airlift Photobioreactor

2019 ◽  
Vol 33 (1) ◽  
pp. 87-98 ◽  
Author(s):  
Yaremi Lopez-Hernandez ◽  
Carlos Orozco ◽  
Ines Garcia-Peña ◽  
Jorge Ramirez-Muñoz ◽  
Luis Torres
Keyword(s):  
Flow Rate ◽  
Chlorella Vulgaris ◽  
Mixing Time ◽  
Air Flow ◽  
Lipid Production ◽  
Biomass Concentration ◽  
Inverse Correlation ◽  
Aeration Rate ◽  
Air Flow Rate ◽  
Lipid Concentration

The effect of different types of spargers and the influence of the air flow rate on biomass and lipids production by Chlorella vulgaris was evaluated. These data allowed correlation of the hydrodynamic behavior of the photobioreactor with the byproducts production. The hydrodynamic characterization was developed by determining the mixing time (tM), hold-up, and total volumetric mass transfer coefficient of CO2, kLa(CO2)T, at increasing air flow rates for three different spargers: star-shaped, cross-shaped and porous glass surface sparger. The hydrodynamic characterization showed that the tM decreased, while the hold-up values and the kLa(CO2)T increased as a result of the increment in the volumetric air flow rate between 5 to 17 L min–1. The highest biomass and lipid concentrations were determined at the higher aeration rate (20 L min–1), which was correlated with the lower tM, the higher hold-up and kLa(CO2)T values. Biomass and lipid production showed an inverse correlation. The highest biomass concentration (750 mg L–1) and the lowest lipid concentration (10 mg L–1) were measured with the star sparger. In contrast, when the lowest biomass concentration was obtained (240 mg L–1), the highest lipid concentration of 196 mg L–1 was measured with the glass sparger. The maximum biomass productivity values were determined at the lower aeration rate and the star sparger, with the minimum power per unit of volume, which could be useful for a cost-effective process.

scholarly journals Effect of magnetic field on biomass properties and their role in biodegradation under condition of low dissolved oxygen

2021 ◽  
Vol 11 (7) ◽  
Author(s):  
Nur Syamimi Zaidi ◽  
Johan Sohaili ◽  
Khalida Muda ◽  
Mika Sillanpää ◽  
Norelyza Hussein
Keyword(s):  
Magnetic Field ◽  
Dissolved Oxygen ◽  
Biomass Concentration ◽  
Aerobic Bacteria ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Great Chance ◽  
Sludge Bulking ◽  
The Magnetic Field ◽  
High Biomass Concentration

AbstractLow condition of dissolved oxygen (DO) is commonly associated with sludge bulking problem that was able to disrupt the efficiency of wastewater treatment performances. Relatively, very little attention was paid to the possibility of applying magnetic field in controlling the bulking problem. Hence, this study aims to investigate the performance of magnetic field on biomass properties and its effect on biodegradation under low condition of DO. Two continuous laboratory-scale sequencing batch reactors—Reactor A (SBRA) and Reactor B (SBRB)—were setup. SBRA was equipped with the magnetic device to exhibit magnetic field of 88 mT, while SBRB acted as a control system. The results showed that the biomass concentration in SBRA was higher compared to SBRB. High biomass concentration in SBRA resulted to better settleability with mean SVI of less than 30 mL/g. SBRA also showed consistently high removal performances of organic and inorganic contents compared to SBRB. These observations confirmed that the magnetic field was able to enhance the biomass properties, which further enhance the biodegradation ability of the aerobic bacteria under low DO condition. This also indicates that under the sludge bulking circumstances, the use of magnetic field stands a great chance in maintaining high biodegradation of the treatment system.

Reoxygenation Rate for Airlift Inner Circulation Reactor

2013 ◽  
Vol 726-731 ◽  
pp. 1926-1929
Author(s):  
Ke Wu Pi ◽  
Min Xia ◽  
Shi Shi ◽  
Qu Xiao
Keyword(s):  
Dissolved Oxygen ◽  
Aeration Rate ◽  
Airlift Reactor ◽  
Liquid Level ◽  
Aeration Tank ◽  
Do Concentration

Airlift inner circulation reactor (AICR) consisting of beaker and built-in aeration tank was introduced in this paper. The Dissolved oxygen recovery (RDO) was highly influenced by the ratios of the height of built-in aeration tank to the height of liquid level in reactor (Rh/H), the diameter of built-in aeration tank to the diameter of the reactor (Rd/D) and aeration rate (QN). Average RDO of 24.25 m.gm-3.s-s and DO concentration of 8.97mg.l-1 were obtained at Rd/D=0.47, Rh/H=0.68 and QN =1.0m3.m-3.min-1 for aerating 370s at 17°C. The total transferred oxygen in 4L deoxidized water reached 35.89mg, which had an increase by 11.15% than that of the traditional airlift reactor (AR). The DO concentration was 88.33-9.34mg.l-1 for AICR, but it’s only 7.71-8.58mg.l-1 for AR.

scholarly journals Correction: Low-cost lipid production by an oleaginous yeast cultured in non-sterile conditions using model waste resources

2014 ◽  
Vol 7 (1) ◽  
pp. 42 ◽  
Author(s):  
Fabio Santomauro ◽  
Fraeya M Whiffin ◽  
Rod J Scott ◽  
Christopher J Chuck
Keyword(s):  
Oleaginous Yeast ◽  
Low Cost ◽  
Lipid Production

scholarly journals A new combined approach to improved lipid production using a strictly aerobic and oleaginous yeast

2018 ◽  
Vol 19 (1) ◽  
pp. 47-56 ◽  
Author(s):  
Fábio Guerreiro ◽  
Ana Constantino ◽  
Emília Lima-Costa ◽  
Sara Raposo
Keyword(s):  
Oleaginous Yeast ◽  
Lipid Production ◽  
Strictly Aerobic ◽  
Combined Approach

scholarly journals Economical lipid production from Trichosporon oleaginosus via dissolved oxygen adjustment and crude glycerol addition

2019 ◽  
Vol 273 ◽  
pp. 288-296 ◽  
Author(s):  
Xiaolei Zhang ◽  
Jiaxin Chen ◽  
Di Wu ◽  
Ji Li ◽  
Rajeshwar Dayal Tyagi ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Crude Glycerol ◽  
Lipid Production

scholarly journals Artificial neural network model and fuzzy logic control of dissolved oxygen in a bioreactor

2020 ◽  
Vol 17 (3) ◽  
pp. 1289
Author(s):  
Nor Hana Mamat ◽  
Samsul Bahari Mohd Noor ◽  
Laxshan A/L Ramar ◽  
Azura Che Soh ◽  
Farah Saleena Taip ◽  
...  
Keyword(s):  
Neural Network ◽  
Fuzzy Logic ◽  
Dissolved Oxygen ◽  
Network Model ◽  
Neural Network Model ◽  
Fermentation Process ◽  
Fuzzy Logic Controller ◽  
Rbf Neural Network ◽  
Aeration Rate ◽  
Process Data

In a fermentation process, dissolved oxygen is the one of the key process variables that needs to be controlled because of the effect they have on the product quality. In a penicillin production, dissolved oxygen concentration influenced biomass concentration. In this paper, multilayer perceptron neural network (MLP) and Radial Basis Function (RBF) neural network is used in modeling penicillin fermentation process. Process data from an industrial scale fed-batch bioreactor is used in developing the models with dissolved oxygen and penicillin concentration as the outputs. RBF neural network model gives better accuracy than MLP neural network. The model is further used in fuzzy logic controller design to simulate control of dissolved oxygen by manipulation of aeration rate.  Simulation result shows that the fuzzy logic controller can control the dissolved oxygen based on the given profile.

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