Yeast manufacturing process

[mk2000]

Can anyone help me understand yeast manufacturing process. Also if they can explain the waste management issues with yeast production and what is COD?

Thank you.

 

[dcasto]

COD Chemical Oxygen Demand Chemical substances which consume oxygen. It is a measure of the amount of oxygen required for the total chemical breakdown of organic substances in water.

BOD Biological Oxygen Demand A measure of the amount of oxygen consumed by micro-organisms in breaking down organic matter in effluent during a certain period.

As a advent brewer I've investigated building and owning a small mirco brewery. I took a class that spent a portion of the time on waste from a brewery, a yeast factory if you please. Yeast has two (i'll buthcer by biology here) strains or families. It is found in the wild. Yeast for consumption is an isolated single yeast cell that is replicated for millions of generations. Most pure bred (pardon the pun) yeasts are patented and some strains can be traced back a couple hundred years. You can by a strain or isolate your own.
Once you have the single strain, the pharse to remmber is Cleanliness is not only next to Godliness, its your livelyhood. Yeast strains must be kept free from all bacteria floating around, including other yeast. Its not that yes bred, its that a new strain may out compete yours and soon you have a new yeast that may not produce the properties you want from your yeast.
At this point feed sterilized food in a sterilize atmosphere and they will go forth and multiply. Good old sugars will work, some better than others, some (lactose) not at all.
Yeast die and fall to the bottom of the vessel and can be removed as waste, along with uneaten food. You have to change the water once in a while because yeast excrete ethanol, which is poisionous to them (but not me).
The dead yeast can be used as feed for cattle and this is where the BOD and COD come in. The waste has protiens and stuff which when dissolved in water pull all the oxygen out and make the water almost useless. So you can oxigenate the water like they do at the sewer plants to put in the water and finalize the distruction of the yeast to nothing.

Pick up a college level biology book or a home brewing book and get filled in on the details and brew a batch at home.

 

[MortenA]

on a side note (i sure dcasto is aware of this): Yeast is not a bacteria - its a destinct group of lifeforms like fubgus, bateria, vira etc.

Best regrads

Morten

 

[mk2000]

dcasto

I was told that the final water is untreatable. However you are saying that it is. Are you sure that the yeast waste and Beer waste are the same?

Regards

 

[dcasto]

With beer, they have a whole bunch of solids (grains) and the waste water is kept to a minimum. Budwiser got in trouble in Colorado as they tried to use the waste water to irrigate local crops, but their was a problem with it. If you use just sugar, the dead yeast cells may have a value if dried, which means you cook the water out and condense it, that water would be reusable. I would assume you would recover the ethanol from the system for fuel?

I really don't know how small you could get the waste water down to, but it will be pretty small based on what the big Coors brewery and Budwiser brewiers say their waste stream is. In my opinion, I would look at what that industry does as a model for waste handling.