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Innovation & Technologie Angebot

New bioreactor for growing plant cell culture in suspension

Country of Origin: Spain
Reference Number: TOES20171129002
Publication Date: 25 January 2018

Summary

A Spanish university developed a bubble column-type bioreactor to carry out the culture of a cell suspension of any type of plant in aseptic conditions. The novel design of this low-cost bioreactor allows: to recover the culture medium, to replace it with another medium, to reuse the remaining biomass for a next culture operation, a homogenous and efficient aeration, and the correct agitation of the culture. Companies interested in licensing or technical cooperation agreements are sought.

Description

Plant cells are grown to produce both biomass and natural compounds. In both cases, the replacement of the culture medium may be necessary, which is an important problem as the manipulation of the culture itself implies a risk of contamination and thus of culture complete spill.



Bioreactors are widely used for growing microorganisms (bacteria, fungi, etc.), both at laboratory and industrial scale. Their design, usually stirred tank driven by mechanical devices, is not always suitable for plant cell suspension culture. They are very sensitive to the shear stress, display a low oxygen demand, a low growth rate, and use to form large aggregates.



In order to design an appropriate bioreactor for a particular bioprocess, it is necessary to know both its cell growth pattern, its metabolism as well as other factors. In addition, it is necessary to optimize and control the bioreactor operating parameters (concentration of dissolved oxygen, pH, temperature, mixing, nutrient supply, etc.) to support the functions of cell survival and production of metabolites of interest.



The existing bioreactors for plant cell culture, usually bubble column- or airlift-type driven by pneumatic turbulence, display the need of a homogenous and constant culture mixing as the main problem to cope with.



Currently, there exists a trend towards the use of disposable plastics as bioreactor building materials. However, the high costs in consumables that go with it are only justified if the obtained products have high market value (e.g, antibodies, vaccines, therapeutic proteins, etc. obtained through mammalian or insect cell cultures).



In this regard, a Spanish research group has developed a novel bioreactor allowing the growth of a plant cell suspension under aseptic conditions in a liquid medium whose composition fulfills the nutritional and physiological requirements of the cells under appropriate physicochemical conditions. This invention solves the technical problems described above as its novel design allows the optimal plant cell culture, thus overcoming the limitations in both biomass and bioactive compounds production in which the exchange of the culture medium is required.



The bioreactor is composed of the three parts (body, cap and bracket) which are properly assembled and sterilized (Figure 1). 

Additionally, the bioreactor can be connected to reservoirs for liquid exchange. These reservoirs are connected through autoclavable silicone hoses to the inlets and outlets of the bioreactor. It can operate in both “batch” and “fed batch” mode .



There exists a 7-liter prototype bioreactor of plant cell culture which has been tested to: 

- Culture of a vitis vinifera cell suspension in batch mode, achieving a 7-fold increase of the initial biomass.

- Extracellular production of trans-resveratrol in "batch" and "fed batch" modes by a vitis vinifera cell suspension, achieving an extracellular concentration of trans-resveratrol higher than 3 g/L, being able to re-use the biomass obtained up to 3 production cycles without loss in the yield. The average length of each cycle was 4 days, with an average resveratrol production of 15 g/cycle.

- Extracellular production of trans-resveratrol in "fed batch" mode coupled to a "batch" culture of a vitis vinifera cell suspension, with an average resveratrol production of 12 g/cycle.



The biomass or the metabolites with commercial interested obtained through the plant cells culture in suspension carried out with this reactor can be of interest for the following industrial sectors:

• Cosmetics.

• Pharmaceutical.

• Cleaning and personal care.

• Nutraceutical.

• Food.

• Agriculture.



The research team is looking for companies interested in exploiting this technology commercially through license agreement or technical cooperation agreement, by providing technological support in those techniques that require high training or sophisticated instruments that are not available to the requesting comp

Advantages and Innovations

The main innovative aspect of this bioreactor is the fact that its design has the optimal characteristics for the plant cells culture with an homogenous and efficient pneumatic aeration and agitation (even at high cell densities). Morever, it allows recovering the culture medium, replacing the culture medium, and re-useing the biomass for the next culture operation.



This novel bioreactor has the following advantages over the currently commercially available stirred tanks or airlift bioreactors of similar size:

• Low cost.

• It allows working in a permanent aseptic environment throughout the process.

• The materials used are re-usable.

• The design is adapted to the growing needs of any type of plant cell culture in suspension.

• Reduction of operational cost versus single use (disposable) models.

• Especially suitable for obtaining products (biomass or metabolites) whose commercial value in the market is low or moderate.

Stage Of Development

Prototype available for demonstration

Stage Of Development Comment

A 7-liter prototype (Figure 2) has been designed and built at laboratory scale. In its construction, re-usable materials (glass and metal) have been used. 



The oxygen radical absorbance capacity (ORAC) analysis of trans-resveratrol obtained from Vitis vinifera cell cultures using this prototype has a relative ORAC value of 4.40, while commercial trans-resveratrol of purity > 98% has an ORAC value of 4.68, so the antioxidant power of the product obtained is 94% compared to the pure product.



After carrying out a cost analysis, it has been concluded that the commercial production of trans-resveratrol using Vitis vinifera cell cultures with this 7-liter prototype, is around 500 €/kg.

Requested partner

- Type of partner sought: Industries

- Specific area of activity of the partner: Cosmetics, pharmaceutical, cleaning and personal care, nutraceutical, food, agriculture.

- Task to be performed: Commercial exploitation of the technology through license agreement; jointly collaboration through technical cooperation agreement to adapt the bioreactor to their particular requirements and/or to test it at industrial scale