correlation
-
enzyme/substrate-
a content of up to 18-19%reduction compounds in the reaction mixture is regarded as a success. Furthermore, the growth of yeasts on this mixture
enabled us to increase the protein content to 12% and even higher.
This fodder is especially good for feeding animals because it
has the following features: a moisture content of 60%; a content of nitrogen-free extractive compounds of 30%
-
including reduction compounds which make up 12% and wet protein also making up 12%.This method is profitable and makes possible the utilization of straw with a high level of efficiency as the protein obtained has a digestibility of 80%. The digestibility of the straw can be further increased after enzymatic processing.
In conclusion the following can be noted: the creation of a new branch of the microbiological industry
-
i.e. proteinproduction on cellulose
-
posed a number of problems to decision- making scientists; the choice of approach to be taken has an effect on the economy and the scale of production. The question of high productivity equipment for surface culture cannot beanswered, but it is precisely this method which is most expedient from the point of view of energy expenditure.
When working with microorganisms it is important to
remember that their vulnerable point lies in their changeability and the possibility of variants being formed that have undesirable characters. Therefore it is necessary to select microorganisms w-ith care. The production of microbial protein requires a 100%
guarantee of the product's safety. This means that when
developing the technological process, not only microbiologists and technologists, but also physicians and livestock experts must be consulted.
T a b l e 1 . P r o t e i n p r o d u c t i o n by growing m i c r o s c o p i c f u n g i on c e l l u l o s e and s t a r c h - c o n t a i n i n g s u b s t r a t e s
S u b s t r a t e used
Method o f growth
P r o t e i n c o n t e n t . $ b e f o r e i n t h e
l o s s of d r y w e i g h t , I proce- f i n i s h e d
s s i n g p r o d u c t c o t t o n h u s k s s u r f a c e
c u l t u r e
c o r n f e e d s u r f a c e 12-15 35-38
c u l t u r e
s t r a w submerged
c u l t u r e n o n s t a n d a r d submerged v e g e t a b l e s c u l t u r e
T a b l e 2 . The d e t e r m i n a t i o n o f c e l l u l a s e ( C 1 ) a c t i v i t y i n protein-enzyme p r e p a r a t i o n s
s u b s t r a t e u t i l i z e d enzyme a c t i v i t y , u n i t / g
c o t t o n h u s k s c o r n f e e d r u s h e s
f r u i t and b e r r y s q u e e z e
T h i s p a p e r was o r i g i n a l l y p r e p a r e d u n d e r t h e t i t l e " M o d e l l i n g f o r Management" f o r p r e s e n t a t i o n a t a N a t e r R e s e a r c h C e n t r e
(U.K. ) Conference on " R i v e r P o l l u t i o n C o n t r o l " , Oxford,
9 - 1 1 A s r i l , 1979.
ANALYSIS OF THE BASIC TRENDS OF O B T A I N I N G
PROTEIN FROM THE WASTES OF THE VEGETABLE
PROCESSING INDUSTRY
G.G. Mikeladze
There a r e t w o main t r e n d s i n r e s o l v i n g t h e problem o f
p r o t e i n d e f i c i e n c y . The f i r s t i s t o i n c r e a s e t h e p r o d u c t i v i t y , of t h e b i o s p h e r e , a n d t h e second t o produce b i o s y n t h e t i c p r o t e i n .
A t t h e p r e s e n t s t a g e o f development i n s c i e n c e and t e c h n o l o g y , t h e way t o i n c r e a s e r e s o u r c e s o f p r o t e i n from n o n t r a d i t i o n a l
s o u r c e s may b e t o o b t a i n p r o t e i n c o n c e n t r a t e d p r o d u c t s and i s o l a t e s from v a r i o u s c e r e a l s and p l a n t s c o n t a i n i n g p r o t e i n .
F o r t h i s p u r p o s e w a s t e m a t e r i a l s from h a r v e s t i n g and t h e p r o d u c t s o f s e c o n d a r y p r o c e s s i n g o f m a t e r i a l s o f v e g e t a b l e and a n i m a l
o r i g i n may be u s e d .
I n t e n s i v e work i s b e i n g c a r r i e d o u t a l l o v e r t h e w o r l d ,
d i r e c t e d t o w a r d s t h i s e n d , i . e . i n c r e a s i n g t h e u s e f u l p r o d u c t i v i t y o f t h e b i o s p h e r e i n r e s p e c t o f p r o t e i n . I n many c o u n t r i e s t h e r e i s a l a r g e t o n n a g e p r o d u c t i o n o f p r o t e i n from s o y b e a n s , and t h e p r o d u c t i o n o f p r o t e i n from s e e d s o f r a p e , s u n f l o w e r s , sesame, c l o v e r and ground n u t s , a s w e l l a s from t h e q r e e n p a r t s o f p l a n t s i s a l s o t a k i n g p l a c e .
A c o n s i d e r a b l e p r o p o r t i o n o f v e g e t a b l e p r o t e i n s a r e u s e d i n f o r a g e , b u t i n t h e n e a r f u t u r e t h e p e r c e n t a g e u s e d i n food w i l l i n c r e a s e and t h i s w i l l improve t h e o v e r a l l e f f i c i e n c y o f t h e i r u s e .
Taking i n t o c o n s i d e r a t i o n t h e s o i l and c l i m a t i c c o n d i t i o n s o f G e o r g i a , it i s v e r y i m p o r t a n t t o produce l e a f p r o t e i n . F o r t h e p r o d u c t i o n o f l e a f p r o t e i n t h e g r e e n p a r t s o f v a r i o u s p l a n t s may be u s e d a s raw m a t e r i a l . The t y p e o f p l a n t s c a n be d i v i d e d
i n t o f o u r g r o u p s .
To t h e f i r s t g r o u p b e l o n g t h e c r e e p i n g p l a n t s , which a r e
Each o f t h e m a t p r e s e n t h a s a d e f i n i t e p l a c e i n t h e whole
chemical properties and conditions to be applied for use as a on the basis of PEC, excelled a control forage in all indices (weight addition by more than 461, requirement of PEC forage for
1
kg live weight less than 351, and the test animals had a high resistance to infection!. We have worked out thetechnology of obtaining protein isolates from PEC obtained by both surface and submerged culture. The
study of
the amino acid composition of the protein isolates showed us that proteinsUTILIZATION OF CELLULOSIC WASTES FOR THE PRODUCTION OF FODDER YEAST AND/OR ETHANOL
G. Nagy, R. Kerekes, P. Somogyi, J. Rezessy-Szabo, and B. Vajda
Up to the present there have been two main trends for the utilization of cellulosic wastes, namely:
a) the combustion of wastes to obtain energy, and b) fermentation processes.
Single cell protein, liquid and gas energy resources,
bioactive materials and chemical basic materials can be produced by fermentation. The production of microbial proteins and
chemical compounds as energy resources are the most important, as there is a considerable shortage of these materials. Known fermentation technologies are expensive and their application is limited to specific types of wastes.
Our aim was to develop a technology which can be used for different kinds of wastes. Wastes are mainly lignocellulosic in type. The decomposition of natural cellulose and lignin is a relatively slow natural process. The microbial destruction of cellulose has been studied intensively, but less is known about lignin
.
Our first task was to find a suitable microorganism for the fermentation of different kinds of wastes. As yeasts are widely used as a protein source in fodder, we prefered to use them instead of bacteria, and thus eliminated the problems which
might emerge in the use of bacteria for feeding. We succeeded in isolating a specialkind.ofC.andida utilis strain whichcan be applied to specially pretreated cellulosic wastes. This strain was isolated from rotting wood. Its generation time is practically identical
(G=l, 3h) to that when either glucose or cellobiose are used.
This value increases by 30% on a carboxy-methyl-cellulose substrate (G=l, 7h) and by 50% on a Macherey-Nagel l4N 300 cellulose powder substrate.
Aslwaste materials from plants do not contain cellulose in a freely usable form, they must be pretreated to make the
cellulose usable so that it can be fermented by our strain. For this purpose we elaborated a method based on the combined use of moderate heat and chemical treatment. Acid hydrolysis of
cellulose has been described as a process where the terminal glucose units cleave step by step. When studying the decay rate of cellulose treated with diluted acid, we found that not only
glucose molecules but also cellobiose and cellodextrin of different molecular sizes were present in the reaction mixture. The
dynamics of this process showed that destruction of the cellulose molecule also took place within the molecule. If we treat
cellulosic wastes with warm, dilute mineral acid (about 0.4 w/w X ) , decomposition can be observed. The cleaved cellulose reacts
simultaneously with lignin and other plant comppnents... . Optimal solubilization depends on the acid concentration, the applied temperature gradient, the reaction time and the nature of the waste used. The solubilization process can be described by non-
linear Hamilton equations and has to be controlled by a computer.
Our technology is based on the simple treatment of decomposing cellulose to make it fermentable under use of our strain.
Cellulosic wastes are cut into ~ i e c e s of 5 cms by means of a chaff-cutter. The cut material is put into the digestor, where it is mixed with dilute mineral acid. Heat treatment is controlled by means of a non-linear temperature gradient according to the
computer trogram described above, keening the final temperature below 100 C. So the process can be carried out by atmospheric pressure. The solid part of the mixture
-
mainly lignin-
mustbe separated on a vacuum drum filter and can be utilized as an energy source for the fermentation process.
The culture medium for fermentation is made from the liquid phase with the addition of inorganic N and P salts and by
adjusting the pH using slaked lime. Otherwise fodder yeast production is carried out by conventional technologies.
Our method can be put into practice using existing fermen- tation plants equipped with a chaff-cutter, a digestor and a filter. It is important to note that in this case a molasses- sterilizer and a clarifying separator are not necessary. The process does not produce more waste as the solid part can be used as an energy source after pretreatment and the fermentation
content of the waste. The quantities of fodder yeast or absolute ethanol produced are shown in the following table.
D r i e d f o d d e r y e a s t A b s o l u t e e t h a n o l
U t i l i z e d w a s t e s ( k g ) (1)
p r o d u c e d from 1 0 0 k g s o f d r y w a s t e
Corn s t a l k 1 1 . 5
-
16.5 14.2-
1 9 . 6Wheat s t r a w 1 2 . 6
-
1 7 . 2 1 5 . 4-
2 0 . 2Wastes o f s u g a r - c a n e 1 8 . 0
-
1 9 . 0 2 2 . 0-
23.6h a r v e s t
Kenaf w a s t e 16.0
-
18.0 2 0 . 0-
22.0M o l a s s e s ( u s i n g
c o n v e n t i o n a l 2 4 . 0
-
26.0 3 0 . 0-
3 3 . 0t e c h n o l o g y )
The c o s t o f t h e p r o d u c t i o n o f f o d d e r y e a s t p r o d u c e d by o u r t e c h n o l o g y m e e t s t h e c o s t o f s o y b e a n s g e n e r a l l y u s e d a s a
p r o t e i n f e e d s t u f f . A s t h e c o s t o f p r o d u c t i o n d e p e n d s m a i n l y on t h e c o s t o f w a s t e t r a n s p o r t a t i o n , i t c a n b e r e d u c e d c o n s i d e r a b l y i f w a s t e s a r e u s e d i n t h e i r p l a c e o f o r i g i n .
A p a t e n t f o r o u r p r o c e s s i s p e n d i n g ; p a t e n t r i g h t s t h e r e - f o r e p r e v e n t u s f r o m p u b l i s h i n g f u r t h e r d e t a i l s a t p r e s e n t . I f you would l i k e f u r t h e r i n f o r m a t i o n , i t c a n b e o b t a i n e d from t h e a u t h o r s d i r e c t l y .
w a s t e
CHAFF
CUTTEdd i l u t e
m i n e r a l a c i d
I
i c a r g a n i c s a l t s
t-
I
I /
I
l i q u i d p h a s e
f i b r o u s
\cas t e f o r s t e a m
p r o d u c t i o n
I
F u r t h e r o p e r a t i o n s a c c o r d i n g t o t h e c o n v e n t i o n a l t e c i i n o l o g i e s 1
for t h e p r o d u c t i o n o f f a d a e r y e a s t
C
F i g u r e 1 . The s t e p s o f t h e p r o c e s s
THE UTILIZATION OF LIGNO- CELLULOSIC WASTE MATERIALS J. Holota, and P. Belianksy
The population of our planet is increasing at a faster rate than our food resources, especially the energy and protein giving components. If we do not work out some convenient technologies for the utilization of non-traditional raw materials, it might be a matter of just a few decades before we are faced with a
serious shortage of food supplies. Many scientists are paying great attention to the problem nowadays.
In Czechoslovakia research has concentrated mainly on the
problems of manufacturing energy and protein giving food components based on non-traditional raw material resources. In theory, some suitable materials are available, for example: synthetic alcohol, n-alkanes, lignocellulosic waste materials, etc. Waste materials which contain saccharidic components and which might be reutilized
are sulphite-spent liquor, and molasses. The two latter mentioned materials are already commonly used for fermentation, but their quantitiessrelimited by new developments in cellulose and sugar manufacturing technologies. Excrements might be utilized for hydrolysis and when detoxicated used for direct feeding or for
fermentation. However, the protein yield is negligible and the economy of the operation dubious. Synthetic alcohol is an
excellent raw material for protein manufacture. The specific yield is high and no waste water is produced. But this process also has disadvantages: 4 tons of petrol are needed to manufacture
1 ton of protein. Manufacturing costs are therefore very high.
Besides, synthetic alcohol is an exactly defined chemical
compound much needed in other more important industries. Synthe- tic alcohol is manufactured on the basis of imported and strategic raw materials. Microbiological transformation of n-alkanes in protein is promising as a process, but at present the carcino- genity of the product has not as yet been established and the costs of installing such a plant are comparatively high.
Manufacture is based on imported raw materials and supplies can not be guaranteed in the long run.
The remaining resources are lignocellulosic materials, in lignin components. It was later proved that, not the quantity of the lignin, but the way it bonds the saccharidic components, causes wood to resist microbiological degradation, much as in nature or in the digestive tracts of ruminants. Our task was to find a treatment which loosens the bonds between the lignin and the saccharidic components of wood, resulting in exposure of the saccharides to the effects of microorganisms in the digestive
tracts of ruminants. The effect of many chemicals has been tested combined with thermal treatment to this end. We finally came
across combinations which gave rise to an increase in digestibility of beech sawdust from an original level of 4-5% to 55-58%. In
order to test digestibility we improved the "in vitro" method, which enables between 50-70% of the samples to be tested in 3 days and obtains results corresponding to those gained by the
"in vivo" method. The treated sawdust was tested in large scale feeding trials with yearling bullocks over a period of 160
days. In comparison a second group of bullocks were fed on a standard diet. Results were very promising. No adverse effects were noted and weight increases were favorable.
One advantage of treated sawdust is that it is an excellent absorbent of various fodder components, e.g. minerals, antibiotics, etc. It is also very suitable for granulation, pelletization and thus may create a good basis for the manufacture of a standard and uniform fodder.
An area in which treated sawdust can be applied is in the feeding of wild animals in the forest and the zoo. For this purpose treated sawdust is mixed with other fodder components has not yet been put into practice. No equipment is sufficiently developed for a continuous technology and the economic effects
practice. Of salts, superphosphate is used as a catalyst by the French Agrifuran method. The big advantage of this method is
in use in the USSR, Germany, Switzerland, Korea, Japan, the USA, and so on. In the boom period after the war, however, all these plants, except those in the USSR, were closed down because they
At the Forest Products Research Institute ( S D W ) in Bratislava we too have formed a team consisting of chemists, bioloqists,
designers, engineers, etc. Using previous knowledge as a starting point, we began by building a hydrolysis plant for continuous
operation with a capacity of 5 kg/h dry weight of sawdust. In the meantime we tested various domestic sources of lignocellulosic waste material in experiments on the lab scale in sealed glass
tubes.
The plant for the continuous process was built over a period of 3 years and has already been completed. Continuity of flow through pre-heated and heated tube reactors is achieved by high pressure using gas bombs and the loading is regulated by a
discharge valve. The operating temperature is kept at 240°c,' pressure at 4MPa, and transflux is 0....50 liters per hour. We aim to use this plant to optimalize technological regimes of hydrolysis of various lignocellulosic materials, to prepare
sufficient quantities of hydrolysates for fermentation experiments, and to concentrate it for feed trials. Because of a shortage of time, we have not managed to carry out many experiments using this plant yet and as yet no final results are available.
The experiments that were conducted and completed were
correlated on plots as shown (see Figs. 1 - 6 ) . The results of bark hydrolysis are of special interest. According to published data the addition of bark to wood chips for hydrolysis is limited to
lo%, but no explanation is given for this. It is true, that bark has a lower specific sugar yield than wood, but because of its greater weight, the total sugar yield obtained from the operation tion and 8 during the purification of the waste water. This means that the polyphenolic components in bark do not hinder its use
In Figures 1-6 the sugar yields obtained by a two-step hydrolysis of various lignocellulosic materials under different conditions is illustrated, with:
the 1st step of hydrolysis being at 1 3 0 ~ ~ ~ 60 mins.
the 2nd step of hydrolysis being at: a = 2 2 0 ' ~ b = 2 0 0 ' ~ c = 1 8 0 ' ~ d = 1 6 0 ~ ~ concentration of H2S04 is: 10,2 mrn1/100g for: a
511 1) for: a, b, c 2,55 " for: a, b , c
1 2 4 8 16
Time / m i d
Figure 1. The Hydrolysis of Wheat Straw
I I
8