IMPROVEMENTS IN THE MANUFACTURE OF YEAST
Year: 1880

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
and Co., Patent Agents, Southampton Buildings, London, for an Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF YEAST." A communication from
abroad by Jacques Rainer, of Vienna, Austria, Doctor of Chemistry.
PROVISIONAL SPECIFICATION left by the said William Robert Lake at the
Office of the Commissioners of Patents on the 21st February 1880.
WILLIAM ROBERT Lake, of the Firm of Haseltine, Lake, and Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN THE MANUFACTURE OF
YEAST." [A communication from abroad by Jacques Rainer, of Vienna, Austria,
Doctor of Chemistry.]
This Invention relates to the manufacture of yeast without the ordinary alcoholic
fermentation and without the ordinary formation of secondary products.
The said improvements consist,-
First. In the employment of vegetable peptones with the addition of small
quantities of dextrose, maltose, or other similar hydro-carbons for the purpose of the
culture and growth of the cells of yeast.
Secondly. In adding successively peptones and sugar to the comparatively
stable nutritious solution used for growing the yeast, and in successively with-
drawing the finished yeast produced in the said solution.
Thirdly. In the manufacture of pressed yeast in large quantities without alcoholic
fermentation and without production of alcohol or vinegar.
Fourthly, In the admission of ozonized air or ozonized oxygen for the purpose
of accelerating and intensifying the growth of the yeast.
According to the present improvements the process of manufacturing the yeast
is carried into practice in the following manner, that is to say :-
.
The vegetable albuminous matters obtained from maize or other grain legumen,
or from waste products, such as bran, the radicles of malt, spent malt, gluten, and
other similar products are treated with water containing a small quantity of an
alkali or of a mineral acid, and the extract is peptonised by the addition of diastaso
in the presenco of diluted acid. In the radicles of malt especially part of the
albuminous matters are already peptonised by the previous growing of the barley,

page_text: and their extract already contains some diastase. According to the quantity of
peptones contained in the fluid a quantity of sugar, dextrose, maltose, or of their
equivalents is added in the proportion of about one-half of the weight of dry
peptones present. This addition ought to be about one half per cent. of the total
quantity of the fluid, and serves solely for the purpose of yielding the material for
the formation of the structure of the cells of yeast. A small quantity of beer
yeast or pressed yeast is also added to start the growth, and atmospheric air or
ozone is conducted into the fluid to accelerate the growth and impede fermentation.
When after some hours the sugar already added has been consumed by the growth
of the yeast, a further portion of about from one-tenth to one-fourth per cent. is
again added, and in a similar manner the peptones already consumed are replaced
by gradual and successive addition of further small quantities of peptones.
The yeast produced may be likewise successively and gradually removed by
skimming it off or by allowing it to settle.
The purification and pressing of the yeast take place in the usual manner.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Robert Lake in the Great Seal Patent Office on the
21st August 1880.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN THE MANUFACTURE OF
YEAST." A communication from abroad by Jacques Rainer, of Vienna, Austria,
Doctor of Chemistry.
This Invention relates to the manufacture of yeast without the ordinary alcoholic
fermentation, and without the ordinary formation of subsidiary products.
The said improvements consist,—
Firstly. In the employment of vegetable peptones with the addition of slight
quantities of dextrose, maltose, or other similar hydrocarbons for the purpose of the
culture and growth of the cells of yeast.
Secondly. In adding successively peptones and sugar to the comparatively stable
nutritious solution used for growing the yeast, and successively withdrawing the
finished yeast produced in the same.
Thirdly. In a process or method of manufacturing compressed yeast in large
quantities without alcoholic fermentation, and without any subsidiary production
of alcohol or vinegar.
Fourthly. In the admission of ozonised air or ozonised oxygen for the purpose of
accelerating and intensifying the growth of the yeast.
According to the present improvements the process of manufacturing the yeast
may be carried into practice in the following manner, that is to say:-
The vegetable albuminous matters obtained from maize or other grain or legumen,
or from waste products, such as bran, the radicles of malt, spent inalt, gluten, and
other similar products are treated with water containing a small quantity of an
alkali or of a mineral acid, and the extract is peptonised by the addition of
diastase in the presence of diluted acid. In the radicles of malt especially part of
the albuminous matters is already peptonized, and their extract already contains
some diastase. According to the quantity of peptone contained in the fluid sugar,
dextrose, maltose, or their equivalent is added in the proportion of about one half
of the weight of dry peptones present. This addition ought to be about one half
per cent of the total quantity of the fluid, and serves solely for yielding the
material for the formation of the structure of the cells of yeast. A small quantity
of beer-yeast or pressed yeast is also added to start the growth, and atmospheric
air or ozone is conducted into the fluid to accelerate such growth. When after
some hours the sugar already added has been consumed by the growth of the
yeast, a further quantity of about one tenth to one fourth per cent. is again added,
and in a similar manner the peptones already consumed are replaced by the gradual
and successive addition of further small quantities.
The yeast produced may be successively and gradually removed by skimming
or by allowing it to settle. The purification and pressing of the yeast take place
in the usual manner.
The process of manufacturing the compressed yeast commercially is as follows:-
The vegetable albuminous substances in the corn cereals or other vegetables, or
such refuse of industrial establishments as bran cornings, malt residuum, gluten,
and the like are extracted with the aid of from 15 to 20 parts by measure of water,
made slightly alkaline. They are then either peptonised by adding an excess of
lactic acid (about 4 per cent.) or mineral acids (about 1% per cent. of phosphoric
acid, or about $10 per cent. of either sulphuric acid or hydrochloric acid) at a
temperature of from 85 to 100 degrees Fahrenheit, or they are at once macerated
in dilute solutions of the above acids and simultaneously converted into peptone.

page_text: A portion of the albuminous substances (from 5 to 10 per cent. of the total weight)
in the dried cornings will be already transformed into peptone by the process of
vegetation. The albuminous substances in cereals, maize, or other vegetables, and
in bran and malt residuum are transformed into peptone by the addition of diastase.
In order to effect the conversion it is sufficient to add to one part by weight of the
albuminous matter when dry one part by weight of dry malt, or five parts by
weight of cornings. As stated the liquid in which the albuminous matter is to be
transformed into peptone must contain lactic acid (4 per cent.), phosphoric acid (as
much as per cent.), sulphuric acid or hydrochloric acid (about 2/3 per cent.),
because the presence of an acid is absolutely necessary in the process of converting
these substances into peptone.
A. temperature of about 100 degrees Fahrenheit is the most suitable for the
conversion of said substances into peptone, and a period of from 18 to 20 hours will
be sufficient to effect it. It may however be also carried out at lower temperatures
during a correspondingly longer time. In working cornings it is superfluous to
add malt, because the diastase contained in the cornings is more than sufficient for
the process of conversion into peptone. Therefore it is only necessary in this case
to use one of the above named acids in the proportions given.
The mixture of the cornings with water may be effected by hand or by means of
a stirring apparatus actuated by any suitable machinery. In mashing malt or
cereals, that is to say, in preparing the necessary maltoso, dextrose, or the like, I
use the apparatus ordinarily employed for such process, care being taken to main-
tain the temperature and other conditions necessary for proper concentration, as
described and recommended in modern technical journals especially in Professor
Dr. Max Maerker's " Handbuch der Spiritus Fabrication" (Handbook of the
Manufacture of Spirits).
The slimy pectates contained in the cornings as well as in other materials are
dissolved by the combination of diastase and acids.
When the preparation of pure peptone is required the pectates may be separated
by an endosmotic apparatus or dialysator, in such a manner that the peptone is
dialysed through proper membranes in water, while the gelatinous pectates remain
as a residuum.
The acids are neutralized by means of soda, or by saturating the liquid with
basic phosphate of lime in the manner hereinafter described.
The prepared peptone liquid, with or without a percentage of sugar, may be
shipped as a saleable article, or it may be delivered in a dry state, or as a syrup or
extract obtained by boiling the liquid down in a water bath, by steam, or preferably
in a vacuum.
The liquid containing peptone may be separated from solid matter (hydrocarbons,
vegetable fibre, or the like) by simple extraction, maceration, or pressure, or by
centrifugal action, or it may be carefully cleaned by filtration or settling. It is
advisable however before cleaning by filtering or settling to neutralize any acid
present by means of soda, or to saturate the liquid with basic phosphate of lime,
the latter being preferable because the phosphoric acid required by the yeast is
thus abundantly furnished to it.
In order to start the growth of the yeast gelatinized starch is added after being
transformed in the usual way into dextrose by boiling with an addition of mineral
acids. In the place of starch thus prepared an addition may be made of maltose,
molasses, or sugar mixed with beer yeast or compressed yeast. The amount thus
added should correspond to the percentage of peptone in the liquid, being one half
of the dry weight of the peptone. The said hydro carbons should however always
be only from 1 to 1 per cent. of the weight of the entire liquid, and should even
then serve exclusively for the formation of the walls of the cells of the yeast.
The vegetation of the yeast will take place most satisfactorily at temperatures
varying from 57 to 64 degrees Fahrenheit. At a higher temperature losses may
easily occur by reason of the partial conversion of the sugar used into coagulated
lactic acid or into alcoholic fermentation, instead of furnishing the yeast with

page_text: substance for cells. The yeast is either propagated, as is the custom in Holland, in
shallow vessels in which the depth of liquid is about five inches, so that a sufficient
quantity of atmospheric air has access thereto; or it may be better and more
safely effected in vats made of wood, glass, masonry, cement, or other suitable
material, into which atmospheric air is conducted by suitable distributors through
tubes or pipes by means of blowers or compressers in a fine state of division. 4
Instead of atmospheric air alone it is more advantageous to use air containing
an increased amount of ozone or of oxygen partially converted into. ozone.
The
latter is prepared by successively adding hydrogen dioxide to the propagating
liquid. The percentage of ozone in the air is increased by means of phosphorus, or
by causing it to pass through a closed vessel in which permanganato of potassa is
mixed with the necessary quantity of mineral acid. The air thus enriched with
ozone is thus allowed to pass into the propagating liquid.
The growth of the yeast will be completed within from 6 to 8 hours after every
sufficient addition of dextrose, maltose, or other material, according to the density
of the propagating liquid used, the temperature of the latter, and the amount of the
ozone in the air. The percentage of peptone of the mass may amount to from 1 to 2
per cent. or more of its weight, while only from half to one per cent. of dextrose
or other hydro carbons is added at each time, in order to be sure to prevent the
formation of coagulated lactic acid or alcoholic fermentation, and the losses
attendant upon it for my process.
When the entire amount or bulk of the dextrose or other sugar added to promote
the growth of the yeast has been consumed after from 6 to 8 hours, a further
quantity thereof, say, from 1/20 to 1/10 per cent. is added. The peptone may also,
after having been consumed, be added in portions, or may be allowed to flow in
gradually and continuously, The same propagating liquid made by successive
replacement of the matter consumed remains in use for weeks or months, unless it
is rendered impure by other substances, or by subsiding fermentation, and thus
made unfit for further use.
In the same manner as the materials necessary for the propagation of the yeast
are added the yeast produced may be successively withdrawn, and only the yeast
suspended in the liquid remains behind as the germ for the ferments of alcohol to
be afterwards formed.
The yeast is obtained either by skimming it from the surface of the liquid or by
separating it from the propagating liquid by filtration, or finally by gathering it
after tapping the vats from the bottom upon which it is deposited in a compact
layer.
In working on a large scale it is advisable to place the vats in terraced batteries
in order to effect the transfer of the propagating liquid from one vessel to the
other with facility.
In order to produce yeast as free as possible from subsidiary ferments the
propagating liquid may be prepared in a more dilute state, that is to say, with a
percentage of peptone of only from 3/, to 1 per cent. The hydrocarbons (dextrose,
maltose, or the like) may also be added in smaller quantities, for example, as n
first dose about 1/3 per cent., and then every 3 hours about 1/2 per cent.
The
The greater part of the peptone present will then be transformed into yeast in
from 12 to 15 hours, a sufficient supply of pure air, if necessary conducted through
sulphuric acid or oxygen containing ozone, being provided, and the entire process
being carried on at a temperature varying from 54 to 63 degrees Fahrenheit.
whole liquid is then cooled by a suitable apparatus, or by adding cold water or ice;
the best temperature being from 45 to 50 degrees Fahrenheit. Within from 36
to 48 hours the yeast obtained will settle on the bottom of the vat. The pro-
pagating liquid may be allowed to flow away. The yeast obtained by this improved
process is purified and condensed in the usual manner, but in order to increase its
durability phosphate of lime amounting to from 4 to 5 per cent. of the total
weight of the yeast to be made may be added before compressing it.
•
Experience has shown that from 250 to 300 parts of pure and active compressed

page_text: yeast may be obtained from 100 parts of pure peptone. For the growth of the
said quantity of yeast only about 200 parts, of dextrose or sugar are required.
Having thus fully described the said Invention as communicated to me by my
foreign correspondent and the manner of performing the same, I wish it understood
that I claim,
First. The process of cultivating the cells of yeast from vegetable peptone by
the addition of dextroso or similar hydrocarbons, substantially as specified.
Second. In making yeast, the process comprising the successive additions of
peptone and hydro-carbons to the propagating liquid, together with the successive
removals of the yoast produced, all substantially in the manner and in the
proportions specified.
Third. The process or method herein described of manufacturing compressed
yeast without alcoholic fermentation, and without producing alcohol or vinegar, as
above set forth.
Fourth. In making yeast the application of currents of ozone to the propagating
liquid for the purpose of accelerating the growth of the yeast, and of increasing
the intensity of its development, substantially as specified."
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this Twenty-first day of August, in the year of our Lord
One thousand eight hundred and eighty.