Automatic inducer addition and harvesting of recombinantEscherichia coli cultures based on indirect on-line estimation of biomass concentration and specific growth rate

2001 ◽  
Vol 75 (3) ◽  
pp. 355-361 ◽  
Author(s):  
Niels Thomas Eriksen ◽  
Irina Kratchmarova ◽  
S�ren Neve ◽  
Karsten Kristiansen ◽  
Jens J�rgen L�nsmann Iversen
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Biomass Concentration ◽  
On Line

scholarly journals Preventing Overflow Metabolism in Crabtree-Positive Microorganisms through On-Line Monitoring and Control of Fed-Batch Fermentations

Fermentation ◽  
2018 ◽  
Vol 4 (3) ◽  
pp. 79 ◽  
Author(s):  
Loïc Habegger ◽  
Kelly Rodrigues Crespo ◽  
Michal Dabros
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Biomass Concentration ◽  
Critical Value ◽  
Overflow Metabolism ◽  
Monitoring And Control ◽  
Fed Batch ◽  
Batch Mode ◽  
On Line

At specific growth rates above a particular critical value, Crabtree-positive microorganisms exceed their respiratory capacity and enter diauxic growth metabolism. Excess substrate is converted reductively to an overflow metabolite, resulting in decreased biomass yield and productivity. To prevent this scenario, the cells can be cultivated in a fed-batch mode at a growth rate maintained below the critical value, µcrit. This approach entails two major challenges: accurately estimating the current specific growth rate and controlling it successfully over the course of the fermentation. In this work, the specific growth rate of S. cerevisiae and E. coli was estimated from enhanced on-line biomass concentration measurements obtained with dielectric spectroscopy and turbidity. A feedforward-feedback control scheme was implemented to maintain the specific growth rate at a setpoint below µcrit, while on-line FTIR measurements provided the early detection of the overflow metabolites. The proposed approach is in line with the principles of Bioprocess Analytical Technology (BioPAT), and provides a means to increase the productivity of Crabtree-positive microorganisms.

An algorithmic approach to constructing the on-line estimation system for the specific growth rate

1989 ◽  
Vol 33 (3) ◽  
pp. 354-364 ◽  
Author(s):  
Hiroshi Shimizu ◽  
Takeichiro Takamatsu ◽  
Suteaki Shioya ◽  
Ken-Ichi Suga
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Algorithmic Approach ◽  
On Line ◽  
Estimation System

Automated fed-batch culture of Kluyveromyces fragilis based on a novel method for on-line estimation of cell specific growth rate

2001 ◽  
Vol 9 (3) ◽  
pp. 221-231 ◽  
Author(s):  
Zairossani M. Nor ◽  
Melih I. Tamer ◽  
Jeno M. Scharer ◽  
Murray Moo-Young ◽  
Eric J. Jervis
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Batch Culture ◽  
Specific Growth ◽  
Fed Batch ◽  
Kluyveromyces Fragilis ◽  
On Line ◽  
Novel Method ◽  
Fed Batch Culture

scholarly journals Pengaruh Komposisi Air Limbah Industri Kertas sebagai Media Pertumbuhan dan Fotoperiode Terhadap Kultur Spirulina platensis

2019 ◽  
Vol 9 (01) ◽  
pp. 9
Author(s):  
Meisa Legi Rizkiana ◽  
Saepulloh Saepulloh ◽  
Prima Besty Asthary ◽  
Rahmaniar Mulyani
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Flue Gas ◽  
Spirulina Platensis ◽  
Doubling Time ◽  
Specific Growth ◽  
Paper Industry ◽  
Biomass Concentration ◽  
Treated Wastewater ◽  
Wet Scrubber

Industri kertas menghasilkan air limbah dari kegiatan produksi dan proses flue gas desulphurization (air limbah wet scrubber). Senyawa nutrisi (senyawa karbon, nitrogen, dan fosfat) yang masih terdapat dalam air limbah terolah dan air limbah wet scrubber belum dimanfaatkan secara optimal dan berpotensi sebagai media pertumbuhan Spirulina platensis. Penelitian dengan variasi komposisi air limbah dan fotoperiode (24 jam terang dan 12 jam terang/12 jam gelap) telah dilakukan dalam skala laboratorium selama 9 hari. Pengukuran pH media, pertumbuhan S. platensis (konsentrasi biomassa, laju pertumbuhan spesifik, dan waktu penggandaan), dan kandungan fikosianin dilakukan setiap hari untuk melihat pengaruh komposisi media dan perlakuan fotoperiode terhadap pertumbuhan S. platensis. Hasil menunjukkan bahwa S. platensis dapat tumbuh dengan baik pada semua komposisi air limbah terolah dan air limbah wet scrubber yang diujicobakan. Konsentrasi biomassa tertinggi sebesar 831 mg/L dan laju pertumbuhan spesifik tertinggi sebesar 0,52 hari-1 dengan waktu penggandaan 0,4 hari diperoleh dari perlakuan fotoperiode 24 jam terang. Komposisi air limbah terolah dan air limbah wet scrubber tidak memberikan pengaruh yang nyata terhadap konsentrasi biomassa, tetapi perbedaan fotoperiode sangat berpengaruh terhadap konsentrasi biomassa sehingga dalam aplikasi skala lapangan perlu mempertimbangkan sistem pencahayaan untuk pertumbuhan S. platensis yang optimal.Kata kunci: Spirulina platensis, media pertumbuhan, fotoperiode, air limbah terolah, air limbah wet scrubberThe Effect of Composition of Paper Industry Wastewater as A Growth Medium and Photoperiod on The Culture of Spirulina platensisAbstractThe paper industry produces wastewater from its production activities and the flue gas desulphurization process (wet scrubber wastewater). Nutritional compounds (carbon, nitrogen and phosphate compounds) which are still in treated wastewater and wet scrubber wastewater have not been utilized optimally and have potential as growth media of Spirulina platensis. Research on wastewater compositions and photoperiod variations (24 hours light and 12 hours light/12 hours dark) was carried out on a laboratory scale for 9 days. Measurements of medium pH, growth of S. platensis (biomass concentration, specific growth rate, and doubling time), and phycocyanin content were carried out every day to study the effect of wastewater composition and photoperiod treatment on the growth of S. platensis. The results showed that S. platensis can grow well on all compositions of treated wastewater and wet scrubber wastewater. The highest biomass concentration of 831 mg/L and the highest specific growth rate of 0.52 days-1 with a doubling time of 0,4 days is obtained from 24-hour light photoperiod treatment. The composition of treated wastewater and wet scrubber wastewater has no significant effect on the biomass concentration but the photoperiod differences greatly influence the biomass concentration so that in the field scale application it is necessary to consider the lighting system for optimal S. platensis growth. Keywords:  Spirulina platensis, growth medium, photoperiod, treated wastewater, wet scrubber wastewater

Estimation and control of non-linear variables in a continuous fermentation process using sliding mode techniques

2011 ◽  
Vol 34 (7) ◽  
pp. 769-779 ◽  
Author(s):  
AFNA Rahman ◽  
SK Spurgeon ◽  
XG Yan
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Substrate Concentration ◽  
Fermentation Process ◽  
Consumption Rate ◽  
Specific Growth ◽  
Sliding Mode ◽  
Biomass Concentration ◽  
Substrate Consumption ◽  
Non Linear

Biomass, substrate or metabolite concentrations are difficult to measure online in fermentation processes because of the lack of reliable, cheap and sterilizable transducers. Currently, many of the measurements required may be determined through offline analysis, which is costly and time consuming. Furthermore, the specific growth rate conditions involved in the fermentation are typically non-linear and uncertain. In this paper, a new variable, the substrate consumption rate, consisting of a combination of substrate concentration, biomass concentration, specific growth rate and yield production coefficient, is introduced to overcome these problems and simplify the non-linear differential equations of the fermentation process. A sliding mode observer, which only requires measurement of substrate concentration, is then developed to solve the estimation problem, providing a soft sensor to estimate the substrate consumption rate. It is shown that the sliding mode exhibited by the corresponding observer error dynamics is exponentially stable. This parameterization and the resulting estimate of biomass concentration are then utilized within a feedback control strategy. Non-linear simulation results in the presence of both parameter uncertainties and external disturbances illustrate the approach.

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