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1.
Chembiochem ; 25(19): e202400178, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-38742869

RESUMO

Natural and pure p-coumaric acid has valuable applications, and it can be produced via bioprocessing. However, fermentation processes have so far been unable to provide sufficient production metrics, while a biocatalytic process decoupling growth and production historically showed much promise. This biocatalytic process is revisited in order to tackle product inhibition of the key enzyme tyrosine ammonia lyase. In situ product removal is proposed as a possible solution, and a polymer/salt aqueous two-phase system is identified as a suitable system for extraction of p-coumaric acid from an alkaline solution, with a partition coefficient of up to 13. However, a 10 % salt solution was found to reduce tyrosine ammonia lyase activity by 19 %, leading to the need for a more dilute system. The cloud points of two aqueous two-phase systems at 40 °C and pH 10 were found to be 3.8 % salt and 9.5 % polymer, and a 5 % potassium phosphate and 12.5 % poly(ethylene glycol-ran-propylene glycol) mW~2500 system was selected for in situ product removal. An immobilized tyrosine ammonia lyase biocatalyst in this aqueous two-phase system produced up to 33 g/L p-coumaric acid within 24 hours, a 1.9-fold improvement compared to biocatalysis without in situ product removal.


Assuntos
Amônia-Liases , Biocatálise , Ácidos Cumáricos , Propionatos , Ácidos Cumáricos/química , Ácidos Cumáricos/metabolismo , Amônia-Liases/metabolismo , Amônia-Liases/química , Propionatos/química , Propionatos/metabolismo , Enzimas Imobilizadas/metabolismo , Enzimas Imobilizadas/química , Concentração de Íons de Hidrogênio , Fosfatos/metabolismo , Fosfatos/química , Propilenoglicóis/química , Propilenoglicóis/metabolismo , Polietilenoglicóis/química , Polietilenoglicóis/metabolismo , Compostos de Potássio
2.
Biotechnol Bioeng ; 118(1): 58-71, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32876954

RESUMO

Extractive fermentation (or in situ product removal (ISPR)) is an operational method used to combat product inhibition in fermentations. To achieve ISPR, different separation techniques, modes of operation and physical reactor configurations have been proposed. However, the relative paucity of industrial application necessitates continued investigation into reactor systems. This article outlines a bioreactor designed to facilitate in situ product extraction and recovery, through adapting the reaction volume to include a settler and solvent extraction and recycle section. This semipartition bioreactor is proposed as a new mode of operation for continuous liquid-liquid extractive fermentation. The design is demonstrated as a modified bench-top fermentation vessel, initially analysed in terms of fluid dynamic studies, in a model two-liquid phase system. A continuous abiotic simulation of lactic acid (LA) fermentation is then demonstrated. The results show that mixing in the main reaction vessel is unaffected by the inserted settling zone, and that the size of the settling tube effects the maximum volumetric removal rate. In these tests the largest settling tube gave a potential continuous volumetric removal rate of 7.63 ml/min; sufficiently large to allow for continuous product extraction even in a highly productive fermentation. To demonstrate the applicability of the developed reactor, an abiotic simulation of a LA fermentation was performed. LA was added to reactor continuously at a rate of 33ml/h, while continuous in situ extraction removed the LA using 15% trioctylamine in oleyl alcohol. The reactor showed stable LA concentration of 1 g/L, with the balance of the LA successfully extracted and recovered using back extraction. This study demonstrates a potentially useful physical configuration for continuous in situ extraction.


Assuntos
Aminas/química , Reatores Biológicos , Álcoois Graxos/química , Ácido Láctico/química , Modelos Químicos
3.
Microb Cell Fact ; 20(1): 114, 2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34098954

RESUMO

BACKGROUND: The current shift from a fossil-resource based economy to a more sustainable, bio-based economy requires development of alternative production routes based on utilization of biomass for the many chemicals that are currently produced from petroleum. Muconic acid is an attractive platform chemical for the bio-based economy because it can be converted in chemicals with wide industrial applicability, such as adipic and terephthalic acid, and because its two double bonds offer great versatility for chemical modification. RESULTS: We have constructed a yeast cell factory converting glucose and xylose into muconic acid without formation of ethanol. We consecutively eliminated feedback inhibition in the shikimate pathway, inserted the heterologous pathway for muconic acid biosynthesis from 3-dehydroshikimate (DHS) by co-expression of DHS dehydratase from P. anserina, protocatechuic acid (PCA) decarboxylase (PCAD) from K. pneumoniae and oxygen-consuming catechol 1,2-dioxygenase (CDO) from C. albicans, eliminated ethanol production by deletion of the three PDC genes and minimized PCA production by enhancing PCAD overexpression and production of its co-factor. The yeast pitching rate was increased to lower high biomass formation caused by the compulsory aerobic conditions. Maximal titers of 4 g/L, 4.5 g/L and 3.8 g/L muconic acid were reached with glucose, xylose, and a mixture, respectively. The use of an elevated initial sugar level, resulting in muconic acid titers above 2.5 g/L, caused stuck fermentations with incomplete utilization of the sugar. Application of polypropylene glycol 4000 (PPG) as solvent for in situ product removal during the fermentation shows that this is not due to toxicity by the muconic acid produced. CONCLUSIONS: This work has developed an industrial yeast strain able to produce muconic acid from glucose and also with great efficiency from xylose, without any ethanol production, minimal production of PCA and reaching the highest titers in batch fermentation reported up to now. Utilization of higher sugar levels remained conspicuously incomplete. Since this was not due to product inhibition by muconic acid or to loss of viability, an unknown, possibly metabolic bottleneck apparently arises during muconic acid fermentation with high sugar levels and blocks further sugar utilization.


Assuntos
Carboxiliases/metabolismo , Catecol 1,2-Dioxigenase/metabolismo , Hidroliases/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Ácido Sórbico/análogos & derivados , Xilose/metabolismo , Carboxiliases/genética , Catecol 1,2-Dioxigenase/genética , Clonagem Molecular , DNA Fúngico , Fermentação , Regulação Fúngica da Expressão Gênica , Glucose/metabolismo , Hidroliases/genética , Hidroxibenzoatos/metabolismo , Microbiologia Industrial , Engenharia Metabólica/métodos , Redes e Vias Metabólicas , Piruvato Descarboxilase/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Ácido Chiquímico/análogos & derivados , Ácido Chiquímico/metabolismo , Ácido Sórbico/isolamento & purificação , Ácido Sórbico/metabolismo
4.
Biotechnol Appl Biochem ; 68(5): 1044-1057, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32931049

RESUMO

Biotechnology and bioengineering techniques have been widely used in the production of biofuels, chemicals, pharmaceuticals, and food additives, being considered a "green" form of production because they use renewable and nonpolluting energy sources. On the other hand, in the traditional processes of production, the target product obtained by biotechnological routes must undergo several stages of purification, which makes these processes more expensive. In the past few years, some works have focused on processes that integrate fermentation to the recovery and purification steps necessary to obtain the final product required. This type of process is called in situ product recovery or extractive fermentation. However, there are some differences in the concepts of the techniques used in these bioprocesses. In this way, this review sought to compile relevant content on considerations and procedures that are being used in this field, such as evaporation, liquid-liquid extraction, permeation, and adsorption techniques. Also, the objective of this review was to approach the different configurations in the recent literature of the processes employed and the main bioproducts obtained, which can be used in the food, pharmaceutical, chemical, and/or fuel additives industry. We intended to elucidate concepts of these techniques, considered very recent, but which emerge as a promising alternative for the integration of bioprocesses.


Assuntos
Biotecnologia , Adsorção , Biocombustíveis , Fermentação , Extração Líquido-Líquido
5.
Bioprocess Biosyst Eng ; 44(10): 2109-2120, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34047828

RESUMO

ε-Poly-L-lysine (ε-PL) is a naturally-occurring L-lysine homopolymer having a broad-spectrum antimicrobial activity and used widely as a food preservative. In the present study, the combined use of immobilization and in situ product removal (ISPR) was evaluated for the production of ε-PL by Streptomyces ahygroscopicus GIM8. Results showed that ε-PL production in the flask cultures decreased from 0.84 to 0.38-0.56 g/L upon immobilization on loofah sponge with different amounts (0.5-3 g in 50 mL medium in a flask). By applying continuous ISPR to the immobilized flask cultures, ε-PL production as high as 3.51 g/L was obtained compared to 0.51 g/L of the control. A satisfactory titer of 1.84 g/L ε-PL could also be achieved with intermittent ISRP (three cycles of ISPR operation during cultivation). Further investigation showed that low levels of ε-PL retained in the broth appeared to favor its biosynthesis. In the repeated-batch fermentation in a 5 L immobilized bioreactor, with continuous ISPR, the final average ε-PL concentration and productivity were 3.35 g/L and 0.797 g/L/day, respectively, and 3.18 g/L and 0.756 g/L/day for the alternative (intermittent ISPR), in comparison to 1.16 g/L and 0.277 g/L/day with no ISPR usage. In the fed-batch fermentation with immobilized cells, the combined use of intermittent ISPR and extra nutrient feeding increased ε-PL concentration and productivity up to 24.57 g/L and 9.34 g/L/day. The fermentation processes developed could serve as an effective approach for ε-PL production and, moreover, the combination could greatly simplify downstream processing for ε-PL separation and purification.


Assuntos
Fermentação , Polilisina/biossíntese , Streptomyces/metabolismo , Reatores Biológicos , Meios de Cultura , Glucose/metabolismo
6.
Bioorg Chem ; 99: 103765, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32213361

RESUMO

A penicillin G acylase (PGA) from Achromobacter xylosoxidans PX02 was newly isolated, and site-directed mutagenesis at three important positions αR141, αF142, ßF24 was carried out for improving the enzymatic synthesis of ß-lactam antibiotics. The efficient mutant ßF24A was selected, and the (Ps/Ph)ini (ratio between the initial rate of synthesis and hydrolysis of the activated acyl donor) dramatically increased from 1.42-1.50 to 23.8-24.1 by means of the optimization of reaction conditions. Interestingly, the efficient enzymatic synthesis of ampicillin (99.1% conversion) and amoxicillin (98.7% conversion) from a high concentration (600 mM) of substrate 6-APA in the low acyl donor/nucleus ratio (1.1:1) resulted in a large amount of products precipitation from aqueous reaction solution. Meanwhile, the by-product D-phenylglycine was hardly precipitated, and 93.5% yield of precipitated ampicillin (561 mM) and 94.6% yield of precipitated amoxicillin (568 mM) were achieved with high purity (99%), which significantly simplified the downstream purification. This was the first study to achieve efficient ß-lactam antibiotics synthesis process with in situ product removal, with barely any by-product formation. The effect enzymatic synthesis of antibiotics in aqueous reaction solution with in situ product removal provides a promising model for the industrial semi-synthesis of ß-lactam antibiotics.


Assuntos
Achromobacter denitrificans/enzimologia , Antibacterianos/biossíntese , Penicilina Amidase/metabolismo , beta-Lactamas/metabolismo , Antibacterianos/química , Simulação de Acoplamento Molecular , Estrutura Molecular , Penicilina Amidase/genética , Penicilina Amidase/isolamento & purificação , Solubilidade , beta-Lactamas/química
7.
Bioprocess Biosyst Eng ; 43(6): 1027-1035, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32055977

RESUMO

Propionic acid (PA) is a valuable organic acid for the food and feed industry, but no bioproduction at industrial scale exists so far. As product inhibition is a major burden for bioprocesses producing organic acids, in situ product removal (ISPR) is desirable. Here, we demonstrate a new strategy to produce PA with a co-culture coupled with ISPR using electrodialysis. Specifically, Bacillus coagulans first produces lactic acid (LA) from sugar(s) and LA is converted to PA using Veillonella criceti. Applying ISPR to the mentioned co-culture, the specific PA yield was increased from 0.35 to 0.39 g g-1 compared to no ISPR usage. Furthermore, the productivity was increased from 0.63 to 0.7 g L-1 h-1 by applying ISPR. Additionally, it was shown that co-consumption of xylose and glucose led to a higher PA productivity of 0.73 g L-1 h-1, although PA yield was only increased slightly up to 0.36 g g-1.


Assuntos
Bacillus coagulans/crescimento & desenvolvimento , Reatores Biológicos , Ácido Láctico/metabolismo , Propionatos/metabolismo , Veillonella/crescimento & desenvolvimento , Técnicas de Cocultura , Glucose/metabolismo , Xilose/metabolismo
8.
Molecules ; 25(8)2020 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-32325737

RESUMO

Monoterpenes, such as the cyclic terpene limonene, are valuable and important natural products widely used in food, cosmetics, household chemicals, and pharmaceutical applications. The biotechnological production of limonene with microorganisms may complement traditional plant extraction methods. For this purpose, the bioprocess needs to be stable and ought to show high titers and space-time yields. In this study, a limonene production process was developed with metabolically engineered Escherichia coli at the bioreactor scale. Therefore, fed-batch fermentations in minimal medium and in the presence of a non-toxic organic phase were carried out with E. coli BL21 (DE3) pJBEI-6410 harboring the optimized genes for the mevalonate pathway and the limonene synthase from Mentha spicata on a single plasmid. The feasibility of glycerol as the sole carbon source for cell growth and limonene synthesis was examined, and it was applied in an optimized fermentation setup. Titers on a gram-scale of up to 7.3 g·Lorg-1 (corresponding to 3.6 g·L-1 in the aqueous production phase) were achieved with industrially viable space-time yields of 0.15 g·L-1·h-1. These are the highest monoterpene concentrations obtained with a microorganism to date, and these findings provide the basis for the development of an economic and industrially relevant bioprocess.


Assuntos
Escherichia coli/metabolismo , Limoneno/metabolismo , Engenharia Metabólica , Escherichia coli/genética , Fermentação , Glicerol/metabolismo , Engenharia Metabólica/métodos , Redes e Vias Metabólicas , Ácido Mevalônico/metabolismo , Monoterpenos/metabolismo
9.
Chemistry ; 25(19): 4871-4884, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30395380

RESUMO

This Minireview highlights the application of crystallization as a very powerful in situ product removal (ISPR) technique in biocatalytic process design. Special emphasis is placed on its use for in situ product crystallization (ISPC) to overcome unfavorable thermodynamic reaction equilibria, inhibition, and undesired reactions. The combination of these unit operations requires an interdisciplinary perspective to find a holistic solution for the underlying bioprocess intensification approach. Representative examples of successful integrated process options are selected, presented, and assessed regarding their overall productivity and applicability. In addition, parallels to the use of adsorption as a very similar technique are drawn and similarities discussed.


Assuntos
Produtos Biológicos/química , Biotecnologia/métodos , Cristalização/métodos , Bactérias/química , Bactérias/enzimologia , Bactérias/metabolismo , Biocatálise , Produtos Biológicos/isolamento & purificação , Produtos Biológicos/metabolismo , Biotecnologia/instrumentação , Cristalização/instrumentação , Desenho de Equipamento , Modelos Moleculares
10.
Biotechnol Bioeng ; 116(9): 2146-2155, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31062868

RESUMO

Soluble cellodextrins (linear ß-1,4-d-gluco-oligosaccharides) have interesting applications as ingredients for human and animal nutrition. Their bottom-up synthesis from glucose is promising for bulk production, but to ensure a completely water-soluble product via degree of polymerization (DP) control (DP ≤ 6) is challenging. Here, we show biocatalytic production of cellodextrins with DP centered at 3 to 6 (~96 wt.% of total product) using coupled cellobiose and cellodextrin phosphorylase. The cascade reaction, wherein glucose was elongated sequentially from α-d-glucose 1-phosphate (αGlc1-P), required optimization and control at two main points. First, kinetic and thermodynamic restrictions upon αGlc1-P utilization (200 mM; 45°C, pH 7.0) were effectively overcome (53% → ≥90% conversion after 10 hrs of reaction) by in situ removal of the phosphate released via precipitation with Mg2+ . Second, the product DP was controlled by the molar ratio of glucose/αGlc1-P (∼0.25; 50 mM glucose) used in the reaction. In optimized conversion, soluble cellodextrins in a total product concentration of 36 g/L were obtained through efficient utilization of the substrates used (glucose: 98%; αGlc1-P: ∼80%) after 1 hr of reaction. We also showed that, by keeping the glucose concentration low (i.e., 1-10 mM; 200 mM αGlc1-P), the reaction was shifted completely towards insoluble product formation (DP ∼9-10). In summary, this study provides the basis for an efficient and product DP-controlled biocatalytic synthesis of cellodextrins from expedient substrates.


Assuntos
Proteínas de Bactérias/química , Celobiose/química , Cellulomonas/enzimologia , Celulose/análogos & derivados , Clostridiales/enzimologia , Dextrinas/química , Glucosiltransferases/química , Oligossacarídeos/química , Celulose/química , Solubilidade
11.
Protein Expr Purif ; 153: 131-137, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30240632

RESUMO

This work describes a novel strategy for the integrated expression and purification of recombinant proteins in Pichia pastoris cultures. Hydrophobins can be used as fusion tags, proteins fused to them alter their hydrophobicity and can be purified by aqueous two-phase systems (ATPS) based on non-ionic surfactants. Here, the consensus dengue virus envelope protein domain III fused to hydrophobin I of Trichoderma reesei was expressed in Pichia pastoris cultures and an in situ product removal by an ATPS using a non-ionic detergent, (Triton X-114) was performed. The protein was produced and purified directly from the yeast culture supernatant both efficiently and with no loss. The purified protein was properly immobilized by adsorption in solid phase and recognized by anti-dengue antibodies, showing its potential for the development of an indirect immunoassay for dengue virus.


Assuntos
Clonagem Molecular/métodos , Vírus da Dengue/química , Proteínas Fúngicas/isolamento & purificação , Proteínas Imobilizadas/isolamento & purificação , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas do Envelope Viral/isolamento & purificação , Sequência de Aminoácidos , Sequência Consenso , Meios de Cultura/química , Vírus da Dengue/genética , Vírus da Dengue/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Proteínas Imobilizadas/química , Proteínas Imobilizadas/genética , Proteínas Imobilizadas/metabolismo , Octoxinol , Pichia/genética , Pichia/metabolismo , Polietilenoglicóis/química , Domínios Proteicos , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Microextração em Fase Sólida/métodos , Trichoderma/genética , Trichoderma/metabolismo , Proteínas do Envelope Viral/química , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismo
12.
Biotechnol Bioeng ; 114(3): 600-609, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27668843

RESUMO

An experimental platform based on scaled-down unit operations combined in a plug-and-play manner enables easy and highly flexible testing of advanced biocatalytic process options such as in situ product removal (ISPR) process strategies. In such a platform, it is possible to compartmentalize different process steps while operating it as a combined system, giving the possibility to test and characterize the performance of novel process concepts and biocatalysts with minimal influence of inhibitory products. Here the capabilities of performing process development by applying scaled-down unit operations are highlighted through a case study investigating the asymmetric synthesis of 1-methyl-3-phenylpropylamine (MPPA) using ω-transaminase, an enzyme in the sub-family of amino transferases (ATAs). An on-line HPLC system was applied to avoid manual sample handling and to semi-automatically characterize ω-transaminases in a scaled-down packed-bed reactor (PBR) module, showing MPPA as a strong inhibitor. To overcome the inhibition, a two-step liquid-liquid extraction (LLE) ISPR concept was tested using scaled-down unit operations combined in a plug-and-play manner. Through the tested ISPR concept, it was possible to continuously feed the main substrate benzylacetone (BA) and extract the main product MPPA throughout the reaction, thereby overcoming the challenges of low substrate solubility and product inhibition. The tested ISPR concept achieved a product concentration of 26.5 gMPPA · L-1 , a purity up to 70% gMPPA · gtot-1 and a recovery in the range of 80% mol · mol-1 of MPPA in 20 h, with the possibility to increase the concentration, purity, and recovery further. Biotechnol. Bioeng. 2017;114: 600-609. © 2016 Wiley Periodicals, Inc.


Assuntos
Produtos Biológicos/isolamento & purificação , Produtos Biológicos/metabolismo , Reatores Biológicos , Técnicas de Cultura Celular por Lotes , Biocatálise , Produtos Biológicos/química , Biotecnologia , Enzimas Imobilizadas/metabolismo , Microbiologia Industrial , Modelos Biológicos , Propilaminas/análise , Propilaminas/química , Propilaminas/isolamento & purificação , Propilaminas/metabolismo , Estereoisomerismo , Transaminases/metabolismo
13.
Bioprocess Biosyst Eng ; 40(9): 1399-1410, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28601941

RESUMO

A hybrid-immobilization method was developed to improve the long-term stability of laminaribiose phosphorylase immobilized on epoxy supports Sepabeads EC-EP/S. Entrapment in chitosan retained all of the enzyme activity depending on the amount of entrapped solid materials and increased half-life by a factor of 10-94.4 h. No enzyme activity loss was determined during 12 times reuse. The immobilization method is also applicable to sucrose phosphorylase immobilized on Sepabeads EC-EP/S. Up to 31.9 g/L laminaribiose were produced in bienzymatic batch experiments with reaction-integrated product separation by adsorption on zeolites.


Assuntos
Quitosana/química , Dissacarídeos/química , Enzimas Imobilizadas/química , Glucosiltransferases/química , Estabilidade Enzimática
14.
ChemSusChem ; : e202400698, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39227316

RESUMO

Poly(ethylene terephthalate) (PET) is a common single-use plastic and a major contributor to plastic waste. PET upcycling through enzymatic depolymerization has drawn significant interests, but lack of robust enzymes in acidic environments remains a challenge. This study investigates in-situ product removal (ISPR) of protons from enzymatic PET depolymerization via a membrane reactor, focusing on the ICCG variant of leaf branch compost cutinase. More than two-fold improvements in overall PET depolymerization and terephthalic acid yields were achieved employing ISPR for an initial PET loading of 10 mgPET mlbuffer-1. The benefit of ISPR was reduced for a lower initial loading of 1 mgPET mlbuffer-1 due to decreased need for pH stabilization of the enzyme-containing solutions. A back-of-envelop analysis suggests that at a modest dilution ratio, ISPR could help achieve savings on caustic base solutions used for pH control in a bioreactor. Our study provides valuable insights for future ISPR developments for enzymatic PET depolymerization, addressing the pressing need for more sustainable solutions towards plastic recycling and environmental conservation.

15.
Front Bioeng Biotechnol ; 11: 1264787, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38026897

RESUMO

In Bacillus fermentation processes, severe foam formation may occur in aerated bioreactor systems caused by surface-active lipopeptides. Although they represent interesting compounds for industrial biotechnology, their property of foaming excessively during aeration may pose challenges for bioproduction. One option to turn this obstacle into an advantage is to apply foam fractionation and thus realize in situ product removal as an initial downstream step. Here we present and evaluate a method for integrated foam fractionation. A special feature of this setup is the external foam column that operates separately in terms of, e.g., aeration rates from the bioreactor system and allows recycling of cells and media. This provides additional control points in contrast to an internal foam column or a foam trap. To demonstrate the applicability of this method, the foam column was exemplarily operated during an aerated batch process using the surfactin-producing Bacillus subtilis strain JABs24. It was also investigated how the presence of lipopeptides and bacterial cells affected functionality. As expected, the major foam formation resulted in fermentation difficulties during aerated processes, partially resulting in reactor overflow. However, an overall robust performance of the foam fractionation could be demonstrated. A maximum surfactin concentration of 7.7 g/L in the foamate and enrichments of up to 4 were achieved. It was further observed that high lipopeptide enrichments were associated with low sampling flow rates of the foamate. This relation could be influenced by changing the operating parameters of the foam column. With the methodology presented here, an enrichment of biosurfactants with simultaneous retention of the production cells was possible. Since both process aeration and foam fractionation can be individually controlled and designed, this method offers the prospect of being transferred beyond aerated batch processes.

16.
Bioengineering (Basel) ; 10(10)2023 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-37892924

RESUMO

Cupriavidus necator is a facultative chemolithotrophic organism that grows under both heterotrophic and autotrophic conditions. It is becoming increasingly important due to its ability to convert CO2 into industrially valuable chemicals. To translate the potential of C. necator into technical applications, it is necessary to optimize and scale up production processes. A previous proof-of-principle study showed that C. necator can be used for the de novo production of the terpene α-humulene from CO2 up to concentrations of 11 mg L-1 in septum flasks. However, an increase in final product titer and space-time yield will be necessary to establish an economically viable industrial process. To ensure optimized growth and production conditions, the application of an improved process design in a gas bioreactor with the control of pH, dissolved oxygen and temperature including a controlled gas supply was investigated. In the controlled gas bioreactor, the concentration of α-humulene was improved by a factor of 6.6 and the space-time yield was improved by a factor of 13.2. These results represent an important step toward the autotrophic production of high-value chemicals from CO2. In addition, the in situ product removal of α-humulene was investigated and important indications of the critical logP value were obtained, which was in the range of 3.0-4.2.

17.
J Biotechnol ; 360: 55-61, 2022 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-36330925

RESUMO

Fermentation technology is commonly used as a mature process to produce numerous products with the help of micro-organisms. However, these organisms are sometimes inhibited by the accumulation of these products or their by-products. One route to circumvent this is via extractive fermentation, which combines the fermentation process with extraction. To facilitate this, novel bioreactor designs are required, such as the semi-partition bioreactor (SPB) which has been recently proposed for in-situ extractive fermentation. The latter combines a fermentation and an extraction unit into a single vessel using a mixer-settler principle. Where the bioproduct is produced in the mixer and removed continuous in the settler. As the SPB functionality is a subject of interest, this study builds on demonstrating different process conditions in the production of a sample bioprocess (lactic acid (LA)) which is susceptible to product inhibition. The results showed a 34.5 g/L LA concentration was obtained in the pH-controlled condition. While LA production can suffer from product inhibition, neutralizing agents can be easily used to curb inhibitory problems, however, the LA fermentation is a simple (and well-studied) example, which can demonstrate an alternative route to avoiding product inhibition (for systems which cannot be rescued using pH control). Hence, to replicate a scenario of product inhibition, two different process conditions were investigated, no pH control with no extraction (non-integrated), and no pH control with integrated extractive fermentation. Key findings showed higher LA concentration in integrated (25.10 g/L) as compared to the non-integrated (14.94 g/L) case with improved yield (0.75 gg-1 (integrated) versus 0.60 gg-1 (non-integrated)) and overall productivity (0.35 gL-1h-1(integrated) versus 0.20 gL-1h-1(non-integrated)) likewise. This is the first demonstration of an SP bioreactor, and shows how the reactor can be applied to improve productivity. Based on these results, the SPB design can be applied to produce any product liable to product inhibition.


Assuntos
Ácido Láctico
18.
Adv Microb Physiol ; 77: 1-35, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-34756209

RESUMO

Microbubbles have been involved in industrial processing since the 1970s with the introduction of dissolved air flotation into common practice. The turn of the century saw microbubbles become regularly used in medical imaging. But in bioprocessing, only this decade has seen rapid advances in R&D, with some bioprocesses, particularly in wastewater treatment, adopted at full industrial scale, and others at pilot scale, such as anaerobic digestion and fermentation, which is full industrial scale for many biomanufacturing and pharmaceutical processes. This article reviews the methods of microbubble generation only briefly, as it turns out only one generation method, fluidic oscillation through microporous diffusers, has the requisite features for introduction into full scale fermentation processes. Subsequently, six fundamental physicochemical hydrodynamics mechanisms that have been exploited by microbubble innovations in bioprocessing are presented and analyzed, particularly for the roles they play in bioprocessing applications. Some examples are drawn with applications to microalgal and yeast processing, as well as usage in wastewater treatment processes. Because the smallest microbubbles can increase rates in some of these six fundamental processes by several orders of magnitude over conventional processing methods, with the optimal contacting patterns, the promise for wider exploitation in bioprocessing is substantial.

19.
Biotechnol Adv ; 36(7): 1801-1814, 2018 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-29864458

RESUMO

The application of conventional organic solvents has been essential in several steps of bioprocesses in order to achieve sufficient economic efficiency. The use of organic solvents is frequently used either to partly or fully replace water in the reaction medium or as a process aid for downstream separation. Nowadays, manufacturers are increasingly requested to avoid and substitute solvents with hazardous potential. Therefore, the solvent selection must account for potential environmental hazards, health and safety problems, in addition to fulfilling the ideal characteristics for application in a process. For the first time, criteria including Environment, Health and Safety (EHS), as well as the technical requirements for reaction and separation have been reviewed, collected and integrated in a single organic solvent screening strategy to be used as a guideline for narrowing down the list of solvents to test experimentally. Additionally, we have also included a solvent selection guide based on the methodology developed in the Innovative Medicines Initiative CHEM21 (IMI CHEM21) project and applied specifically to water-immiscible solvents commonly used in bioprocesses.


Assuntos
Biotecnologia , Biotransformação , Solventes , Reatores Biológicos , Ácidos Carboxílicos
20.
N Biotechnol ; 42: 56-61, 2018 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-29476815

RESUMO

Increasing demand for natural fragrance ingredients and products has led to their global market growth. 2-Phenylethanol (2-PE) is a volatile substance widely used in food and cosmetics manufacturing. It is generally known that yeast can metabolize l-phenylalanine (l-Phe) to produce 2-PE. However, because the product exhibits an inhibitory effect on yeast cells, simple batch cultivation is uneconomic. The aim of this study was to enhance 2-PE productivity using in situ product removal. Here we present a new method of 2-PE production by yeast in a biphasic system with rapeseed oil as the second phase. The chosen solvent is safe, inexpensive and suitable for the extraction of 2-PE. In addition, rapeseed oil appeared to be a valuable source of intermediates for 2-PE synthesis as its presence in the yeast culture significantly enhanced productivity. The process is an environmentally friendly route and gives two final products that can be considered natural: rapeseed oil with a rose odor and pure 2-PE. Both may be subsequently used as food or cosmetics additives. The results obtained are competitive with previously reported values, as it was possible to enhance the overall concentration of 2-PE by 2.7-fold. The total 2-PE concentration in the biphasic system in the 4.5-L biofermentor used was increased to 9.79 g/L, while the 2-PE concentration in the organic phase attained a value of 18.50 g/L.


Assuntos
Fenilalanina/metabolismo , Álcool Feniletílico/metabolismo , Óleo de Brassica napus/química , Saccharomyces cerevisiae/metabolismo
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