Rheological characteristic of a batch cultivation ofAgrobacterium radiobacter

AbstractTo meet the present and forecasted market demand, bacterial alkaline phosphatase (ALP) production must be increased through innovative and efficient production strategies. Using sugarcane molasses and biogenic apatite as low-cost and easily available raw materials, this work demonstrates the scalability of ALP production from a newfound Bacillus paralicheniformis strain APSO isolated from a black liquor sample. Mathematical experimental designs including sequential Plackett–Burman followed by rotatable central composite designs were employed to select and optimize the concentrations of the statistically significant media components, which were determined to be molasses, (NH4)2NO3, and KCl. Batch cultivation in a 7-L stirred-tank bioreactor under uncontrolled pH conditions using the optimized medium resulted in a significant increase in both the volumetric and specific productivities of ALP; the alkaline phosphatase throughput 6650.9 U L−1, and µ = 0.0943 h−1; respectively, were obtained after 8 h that, ameliorated more than 20.96, 70.12 and 94 folds compared to basal media, PBD, and RCCD; respectively. However, neither the increased cell growth nor enhanced productivity of ALP was present under the pH-controlled batch cultivation. Overall, this work presents novel strategies for the statistical optimization and scaling up of bacterial ALP production using biogenic apatite.

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Semi-batch cultivation of Chlorella sorokiniana AK-1 with dual carriers for the effective treatment of full strength piggery wastewater treatment

Bioresource Technology ◽

10.1016/j.biortech.2021.124773 ◽

2021 ◽

Vol 326 ◽

pp. 124773

Author(s):

Chun-Yen Chen ◽

En-Wei Kuo ◽

Dillirani Nagarajan ◽

Cheng-Di Dong ◽

Duu-Jong Lee ◽

...

Keyword(s):

Wastewater Treatment ◽

Effective Treatment ◽

Batch Cultivation ◽

Chlorella Sorokiniana ◽

Piggery Wastewater ◽

Full Strength

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Optimization of Synthetic Media Composition for Kluyveromyces marxianus Fed-Batch Cultivation

Fermentation ◽

10.3390/fermentation7020062 ◽

2021 ◽

Vol 7 (2) ◽

pp. 62

Author(s):

Konstantins Dubencovs ◽

Janis Liepins ◽

Arturs Suleiko ◽

Anastasija Suleiko ◽

Reinis Vangravs ◽

...

Keyword(s):

Kluyveromyces Marxianus ◽

Reaction Medium ◽

Value Added ◽

Batch Cultivation ◽

Batch Processes ◽

Biomass Growth ◽

High Cell ◽

Media Composition ◽

Fed Batch ◽

Fed Batch Cultivation

The Kluyveromyces marxianus yeast recently has gained considerable attention due to its applicability in high-value-added product manufacturing. In order to intensify the biosynthesis rate of a target product, reaching high biomass concentrations in the reaction medium is mandatory. Fed-batch processes are an attractive and efficient way how to achieve high cell densities. However, depending on the physiology of the particular microbial strain, an optimal media composition should be used to avoid by-product synthesis and, subsequently, a decrease in overall process effi-ciency. Thus, the aim of the present study was to optimise the synthetic growth medium and feeding solution compositions (in terms of carbon, nitrogen, phosphorous, magnesium, and calcium concentrations) for high cell density K. marxianus fed‑batch cultivations. Additionally, the biomass yields from the vitamin mixture and other macro/microelements were identified. A model predictive control algorithm was successfully applied for a fed-batch cultivation control. Biomass growth and substrate consumption kinetics were compared with the mathematical model predictions. Finally, 2‑phenylethanol biosynthesis was induced and its productivity was estimated. The determined optimal macronutrient ratio for K. marxianus biomass growth was identified as C:N:P = 1:0.07:0.011. The maximal attained yeast biomass concentration was close to 70 g·L-1 and the 2-PE biosynthesis rate was 0.372 g·L−1·h−1, with a yield of 74% from 2-phenylalanine.

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Design and Application of an In Situ Test Device for Rheological Characteristic Measurements of Liquefied Submarine Sediments

Journal of Marine Science and Engineering ◽

10.3390/jmse9060639 ◽

2021 ◽

Vol 9 (6) ◽

pp. 639

Author(s):

Hong Zhang ◽

Xiaolei Liu ◽

Anduo Chen ◽

Weijia Li ◽

Yang Lu ◽

...

Keyword(s):

Yellow River ◽

Rheological Characteristic ◽

Yellow River Delta ◽

Turbidity Currents ◽

Rheological Characteristics ◽

Submarine Landslides ◽

Test Device ◽

Offshore Area ◽

In Situ Test

Liquefied submarine sediments can easily lead to submarine landslides and turbidity currents, and cause serious damage to offshore engineering facilities. Understanding the rheological characteristics of liquefied sediments is critical for improving our knowledge of the prevention of submarine geo-hazards and the evolution of submarine topography. In this study, an in situ test device was developed to measure the rheological properties of liquefied sediments. The test principle is the shear column theory. The device was tested in the subaqueous Yellow River delta, and the test results indicated that liquefied sediments can be regarded as “non-Newtonian fluids with shear thinning characteristics”. Furthermore, a laboratory rheological test was conducted as a contrast experiment to qualitatively verify the accuracy of the in situ test data. Through the comparison of experiments, it was proved that the use of the in situ device in this paper is suitable and reliable for the measurement of the rheological characteristics of liquefied submarine sediments. Considering the fact that liquefaction may occur in deeper water (>5 m), a work pattern for the device in the offshore area is given. This novel device provides a new way to test the undrained shear strength of liquefied sediments in submarine engineering.

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