Hi Michaela,

I recently published a paper on the disruption of cell walls and the release of protein from the biomass (mycoprotein) of the filamentous fungus Fusarium venenatum (the main ingredient of the meat-substitutes products branded as Quorn). I used homogenisation, glass beads grinding, and ultra-sonication to disrupt the cell walls. Then, I measured the particle size of the cell debris by static light scattering and visualised by brightfield and fluorescence microscopy.

Although yeasts are unicellular while mycoprotein is multicellular (hyphae), the fungal cell wall may behave similarly.

More info below:

Article Protein bioaccessibility from mycoprotein hyphal structure: ...

Regards,

Raffaele

Dear Michaela Barinova,

I have attached some articles about pilot or industrial techniques for cell disruption. I hope they would be useful.

Dear Michaela Barinova,

I have attached one book which in chapter 6, the cell disruption methods have been discussed.

I suggest Article Cell-wall disruption and lipid/astaxanthin extraction from m...

Article Energy consumption and water-soluble protein release by cell...

Dear Raffaele, Mina and Muhammad,

Thank you so much for your valuable recommendations and experience, and for sharing of your work.

Michaela

Please find it

Generally, cell disruption protocols can be divided into two main categories – the gentle cell disruption protocols (temperature treatments and osmotic and chemical lysis) and the harsher ones (mechanical, ultrasonic and pressure homogenization). So, which technique should you use to increase your chances of success?

5 Common Cell Disruption Methods

1) Mechanical Homogenization

2) Ultrasonic Homogenization

3) Pressure Homogenization

4) Temperature Treatments

5) Osmotic and Chemical Lysis

Chandan Mahata Tanaji Lokare Thank you very much much for your answers. Michaela

Dear Michaela Barinova ,

Very interesting and trending question, but the topic which deals with this processes is too broad, since there are several factors that have to be taken into account for choosing the right method for a specific cell-disruption application. For industrial or pilot plant application I think there is consensus in the literature that the main conventional technologies are the following: bead mill and high-pressure homgenization, considering both energy and cell-disruption efficiencies. However, the energetic efficiencies of these techniques are still far from being good. So we can say that up to date there is not an "ideal" disruption technique that fits all the processing demands, since these depend on many factors as to the inversion costs, value-added of the final product, lability of the product to be extracted, type of microorganism, as well as health and safety considerations. For example, you cannot use an expensive disruption technique if your product does not have a value-added which justifies the use of such technology; that is the case of lipid extraction from microalgae for biofuels production. There are a number of technologies that are being used as alternatives to the conventional ones, but again, they have pros and cons that need to be carefuly considered before taking decisions. The most promising of these may be the microwave and ultrasound technologies, but the industrial use of these processes have been hampered due to their scaling-up difficulties.

As for the way to measure the cell-disruption efficiency, many authors report SEM images to try to indicate the level of cell-disruption, but this is not quantitative. Others use UV-vis spectrophotometry of the disrupted broth; however, you should be careful with this method as it may have important interferences from the macromolecules present in medium. If you really want to quantify this, I would perform a general-microbiology enumeration method of viable cells.

Hope this helps. Regards.

Dear Rogelio Valadez-Blanco ,

Thank you so much for your comprehensive insight. You have practically confirmed what I start to realize, that (with a little exaggeration) if I want an industrially feasible and economically viable method for cell disruption, I´ll have to invent one.

A process/chemical engineering approach to the key steps of the technological process is a rational way to go, there is still a wide niche for optimization and it can considerably reduce the production/operation costs even if the technology is not „perfect“. Especially definition of the product is important, as you suggest, because its application potential defines the economical viability, return on investment and thus available technological procedure(s).

Thank you once more.

With Best Regards,

Michaela

Dear Michaela Barinova ;

I´´m glad that my answer was useful for you. I liked very much your "process/chemical engineering" approach because that is the way engineers have to tackle technical challenges both in science and in industry. I wish you success on your project. If possible I would be interested to know the outcome of that when you have some results.

Best regards,

Rogelio.

A very efficient full-scale yeast cell disruption system was operated in a fodder yeast plant producing fodder yeast from spent sulfite liquor.

There was the following sequence of technological steps:

i) separation and washing of yeasts using a centrifuge

ii) vacuum evaporation of yeast cream at increased temperature - this step served as a thickening stage, cell disruption stage, and reduction of the viscosity of yeast cream before spray drying

iii) spray drying

The plant was operated approx. 22 years with the production rate of 24,000

tons a year of dried fodder yeast.

Best regards

Vit

Dear Vit Mateju ,

Thank you very much for your valuable answer. The information led me to your article in Kvasny prumyl where I have found other interesting details.

With Best Regards,

Michaela