scholarly journals Intensive Multiple Sequential Batch Simultaneous Saccharification and Cultivation of Kluyveromyces marxianus SS106 Thermotolerant Yeast Strain for Single-Step Ethanol Fermentation from Raw Cassava Starch

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 898 ◽  
Author(s):  
Kwanruthai Malairuang ◽  
Morakot Krajang ◽  
Rapeepong Rotsattarat ◽  
Saethawat Chamsart
Keyword(s):  
Yeast Cell ◽  
Cell Density ◽  
Ethanol Fermentation ◽  
High Cell Density ◽  
Batch Process ◽  
Cassava Starch ◽  
Single Step ◽  
Thermotolerant Yeast ◽  
High Cell ◽  
Simultaneous Saccharification

We developed the intensive multiple sequential batch simultaneous saccharification and cultivation of the selected thermotolerant yeast strain for single-step ethanol production. The selection and high-cell-density inoculum production of thermotolerant yeast able to produce ethanol under the optimal conditions for single-step ethanol fermentation has become a necessity. In this study, the newly isolated Kluyveromyces marxianus SS106 could tolerate high temperatures (35–45 °C) and grow under a wide range of pH values (3.0–5.5), which are the optimum conditions of raw cassava starch hydrolyzing enzyme used in single-step ethanol fermentation. The high-cell-density concentration of K. marxianus SS106 was produced by a single batch and an intensive multiple sequential batch process in a 5-L stirred tank bioreactor using the simultaneous saccharification and cultivation (SSC) method. The single SSC process yielded the yeast cell biomass at a concentration of 39.30 g/L with a productivity of 3.28 g/L/h and a specific growth rate of 0.49 h−1. However, the yeast cell density concentration was higher in the intensive multiple sequential batch SSC than in the single batch process. This process yielded yeast cell biomass at concentrations of 36.09–45.82 g/L with productivities of 3.01–3.82 g/L/h and specific growth rates of 0.29–0.44 h−1 in the first six batch cycle. The results suggested that the intensive multiple sequential batch simultaneous saccharification and cultivation of K. marxianus SS106 would be a promising process for high-cell-density yeast production for use as the inoculum in single-step ethanol fermentation. Furthermore, we also experimented with single-step ethanol production from raw cassava starch by K. marxianus SS106 in a 5-L stirred tank fermenter. This produced ethanol at a concentration of 61.72 g/L with a productivity of 0.86 g/L/h.

scholarly journals Bacillus subtilis High Cell Density Fermentation Using a Sporulation-Deficient Strain for the Production of Surfactin

2021 ◽  
Author(s):  
Peter Klausmann ◽  
Katja Hennemann ◽  
Mareen Hoffmann ◽  
Chantal Treinen ◽  
Moritz Aschern ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Cell Density ◽  
High Cell Density ◽  
High Titer ◽  
Batch Process ◽  
High Cell ◽  
Fed Batch ◽  
Fourfold Increase ◽  
High Cell Density Fermentation ◽  
Surfactin Production

Abstract Bacillus subtilis 3NA is a strain capable of reaching high cell densities. A surfactin producing sfp+ variant of this strain, named JABs32, was utilized in fed-batch cultivation processes. Both a glucose and an ammonia solution were fed to set a steady growth rate μ of 0.1 h-1. In this process, a cell dry weight of up to 88 g L-1 was reached after 38 h of cultivation, and surfactin titers of up to 26.5 g L-1 were detected in this high cell density fermentation process, achieving a YP/X value of 0.23 g g-1 as well as a qP/X of 0.007 g g-1 h-1. In sum, a 21-fold increase in surfactin titer was obtained compared with cultivations in shake flasks. In contrast to fed-batch operations using Bacillus subtilis JABs24, an sfp+ variant derived from B. subtilis 168, JABs32, reached an up to fourfold increase in surfactin titers using the same fed-batch protocol. Additionally, a two-stage feed process was established utilizing strain JABs32. Using an optimized mineral salt medium in this high cell density fermentation approach, after 31 h of cultivation, surfactin titers of 23.7 g L-1 were reached with a biomass concentration of 41.3 g L-1, thus achieving an enhanced YP/X value of 0.57 g g-1 as well as a qP/X of 0.018 g g-1 h-1. The mutation of spo0A locus and an elongation of AbrB in the strain utilized in combination with a high cell density fed-batch process represents a promising new route for future enhancements on surfactin production. Key points • Utilization of a sporulation deficient strain for fed-batch operations • High cell density process with Bacillus subtilis for lipopeptide production was established • High titer surfactin production capabilities confirm highly promising future platform strain

Use of chemostat data for modelling extracellular-inulinase production by Kluyveromyces marxianus in a high-cell-density fed-batch process

1995 ◽  
Vol 79 (1) ◽  
pp. 54-58 ◽  
Author(s):  
Marco C.M. Hensing ◽  
Johannes S. Vrouwenvelder ◽  
Chris Hellinga ◽  
Johannes P. Van Dijken ◽  
Jack T. Pronk
Keyword(s):  
Cell Density ◽  
Kluyveromyces Marxianus ◽  
High Cell Density ◽  
Batch Process ◽  
High Cell ◽  
Fed Batch

scholarly journals High Cell Density Cultivation of A Recombinant Bacillus Subtilis for Nattokinase Production

2020 ◽  
Author(s):  
Jianhua Zhang ◽  
Qing Cui ◽  
Bingjun Qian ◽  
Xiangjun Sun
Keyword(s):  
Enzyme Activity ◽  
Bacillus Subtilis ◽  
Cell Density ◽  
Large Scale ◽  
High Cell Density ◽  
Specific Activity ◽  
Feeding Strategy ◽  
Batch Process ◽  
High Cell ◽  
Fed Batch

Abstract Background: Nattokinase (NK), a fibrinolytic enzyme, can be produced by culturing recombinant Bacillus subtilis in Luria-Bertani broth in a shaking flask. For use as a nutraceutical, however, a large-scale preparation and a simple purification process are required.Results: The present study utilized a fed-batch process to cultivate a B. subtilis strain carrying a pHT01 plasmid with an NK-encoding gene (B. subtilis/pHT01-aprN1). For batch A (FB A), with a pH-stat two-stage fermentation strategy, we achieved an activity of 2910.5 ± 21.6 U mL-1 and a specific activity of 30.32 U ml-1 OD600-1. Then, we changed the strategy with a later induction and lower feeding rate to pursue higher cell density and thus higher enzyme activity, a 11.9-fold activity of 4521.8 ± 23.8 U mL-1 was acquired, however, the specific activity was lower than FB A. For the third batch, low-glycerol-level-maintain feeding strategy was followed, and finally, a NK activity of 7778 ±17.28 U mL-1 was obtained, according to our knowledge, it was the highest activity assayed by the fibrin plate method ever reported. Furthermore, fermentation supernatant was successively purified by ammonium sulfate precipitation and nickel column affinity chromatography with a total NK recovery rate of 65.2%.Conclusions: Our results indicate that there is a balance between the cell growth rate and NK expression when recombinant Bacillus subtilis is cultured with a fed-batch process. The equilibrium state can be attained by optimizing the induction and feeding strategy, and thus a high cell density and enzyme activity can be achieved.

High cell density ethanol fermentation in an upflow packed-bed cell recycle bioreactor

2008 ◽  
Vol 13 (2) ◽  
pp. 123-135 ◽  
Author(s):  
Ho Nam Chang ◽  
Byoung Jin Kim ◽  
Jong Won Kang ◽  
Chang Moon Jeong ◽  
Nag-Jong Kim ◽  
...  
Keyword(s):  
Cell Density ◽  
Ethanol Fermentation ◽  
High Cell Density ◽  
Packed Bed ◽  
High Cell ◽  
Cell Recycle
Sign in / Sign up

Export Citation Format

Share Document