scholarly journals Enzymatic hydrolysis of plant raw materials: state and prospects

Author(s):  
V. S. Boltovsky

Plant raw materials are practically an inexhaustible natural resource, since they are constantly renewed in the process of plant photosynthesis, which determines the prospects for their use for industrial processing in various ways, including hydrolytic. The main biopolymer components of plant biomass in terms of their quantitative content are polysaccharides, the hydrolytic processing of which by acidic or enzymatic hydrolysis leads to the formation of monosaccharides and various products obtained from them. This review of scientific literature analyzes theoretical concepts and the current state of research on the development, improvement and prospects for the use of enzymatic hydrolysis of plant raw materials. The efficiency of this process and the composition of the resulting products largely depend on the features of the supramolecular structure of cellulose, the content of hemicelluloses and lignin in the raw material, the balance and activity of the cellulase complex of enzymes. It is shown that the main directions of development and improvement of the processes of enzymatic hydrolysis of plant raw materials at present are the production and use of more effective strains of microorganisms that produce highly active enzymes, the directed creation of complex enzymes (hydrolyzing not only cellulose, but also hemicellulose, as well as destroying lignin), the development of methods for pretreatment of raw materials to increase the reactivity of cellulose and remove lignin and improve the processes of fermentolysis.

Author(s):  
V. S. Boltovsky

Prospects for the development of hydrolysis production are determined by the relevance of industrial use of plant biomass to replace the declining reserves of fossil organic raw materials and increasing demand for ethanol, especially for its use as automobile fuel, protein-containing feed additives that compensate for protein deficiency in feed production, and other products. Based on the review of the research results presented in the scientific literature, the analysis of modern methods of liquid-phase acid hydrolysis of cellulose and various types of plant raw materials, including those that differ from traditional ones, is performed. The main directions of increasing its efficiency through the use of new catalytic systems and process conditions are identified. It is shown that the most promising methods for obtaining monosaccharides in hydrolytic processing of cellulose and microcrystalline cellulose, pentosan-containing agricultural waste and wood, are methods for carrying out the process at elevated and supercritical temperatures (high-temperature hydrolysis), the use of new types of solid-acid catalysts and ionic liquids. 


2019 ◽  
Vol 35 (2) ◽  
pp. 766-772
Author(s):  
Zhaksylyk Baumanuly Makhatov ◽  
Bakhytzhan Shilmirzaevich Kedelbayev ◽  
Madina Dzhakashyeva ◽  
Amina Daulbai ◽  
Bibilgul Zaydullayevna Doltayeva ◽  
...  

The processes of acid and enzymatic hydrolysis of wheat straw in the presence of the strain Aspergillus awamori F-RKM 0719 has been studied. Enzymatic hydrolysis is the most promising method of processing plant biomass. When carrying out the enzymatic hydrolysis of cellulosic materials, the yield of sugars reaches less than 20% of the theoretically possible yield. Overcoming the physico-chemical barriers that hamper the availability of cellulose for enzymes is an important issue, the solution of which is directly related to the search for low-cost pre-treatment methods for raw materials. The effectiveness of this process determines the yield of the target product in the process of enzymatic hydrolysis of cellulose and the economic feasibility of the entire technology as a whole.


2020 ◽  
Vol 13 (6) ◽  
pp. 13-23
Author(s):  
O. Obodovych ◽  

The use of plant biomass as a primary source of energy is currently unacceptable both from an economic and environmental point of view. The experience of a number of industries, in particular hydrolysis production, enables to solve the problem of profitability of organic biomass treatment by its deep complex processing with the resulting components whose cost exceeds the cost of organic raw materials as fuel. Currently, the main results of complex processing of organic raw materials are still energy-intensive products ̶ bioethanol and hydrolyzed lignin, which energy characteristics are commensurate with fossil fuels. Bioethanol production from starch-containing, sugar-containing or lignocellulosic raw materials requires the use of different technological stages and, accordingly, the cost of bioethanol for each type of raw material is different. Compared to bioethanol produced from sugar and starch raw materials, bioethanol manufactured from lignocellulosic raw materials is more expensive. Bioethanol obtained from lignocellulosic raw materials is more expensive compared to bioethanol from sugar and starch raw materials. The most energy-intensive in the technology of bioethanol obtaining from lignocellulosic raw materials is the stage of pretreatment of raw materials for hydrolysis, because the process of preliminary preparation and hydrolysis with dilute acids occurs at high temperatures and pressures. During enzymatic hydrolysis, the process temperature is maintained for a long time (up to several days). To ensure deep integrated processing of plant raw materials, as well as to reduce overall costs, it was proposed to improve the technology and equipment, which allow increasing the degree of conversion of raw materials into basic and by-products.


1982 ◽  
Vol 21 (4) ◽  
pp. 329-333
Author(s):  
Rashid Aziz

The book under review is a concise but fairly in-depth study of the prospects for export diversification from the Less Developed Countries (henceforth labeled as LDCs) particularly to Developed Countries (henceforth labeled as OCs). Given the multiple problems faced by the LOCs in exporting to the OCs - protectionist policies with regards to manufactured exports, volatility of prices obtained for raw material exports, etc. - the study analyses the potential for following an intermediate route. The important issues in the export of semi -processed and wholly processed raw materials are discussed. 111ese issues range from the problems and potentials for the location of processing facilities in the LOCs to the formulation of appropriate policies to encourage an export of processed goods rather than raw materials. Such policies will be useful both in solving the balance of-payments problems of the LDCs and in attaining the goal of the Lima Declaration and Plan of Action on Industrial Development and Co-operation, that called for 2S percent of world industrial production to be located in the LOCs by the year 2000.


Author(s):  
I. A. Ilina ◽  
I. A. Machneva ◽  
E. S. Bakun

  The article is devoted to the study of the chemical composition, physical and thermal-pfysical characteristics of damp apple pomaces and the identifying patterns of influence of drying temperature the functional composition and gel-forming ability of pectin. The research is aimed at obtaining initial data for the subsequent calculation of the main technological, hydro-mechanical, thermal, structural and economic characteristics of devices for drying the plant raw materials, ensuring the environmental safety and high quality of pectin-containing raw materials, the reducing heat and energy costs. As a result of the study of the thermal characteristics of apple pomaces, the critical points (temperature conductivity – 16.5 x 10-8 m2/s, thermal conductivity – 0.28 W/m K, heat capacity – 1627 j/(kg K)) at a humidity of 56 % are determined, which characterizing the transition from the extraction of weakly bound moisture to the extraction of moisture with strong bonds (colloidal, adsorption). It was found that the pomaces obtained from apples of late ripening have a higher content of solids (21-23 %), soluble pectin and protopectin (2.5-4.5 %). Dried pomaces obtained from apple varieties of late ripening contain up to 25 % pectin, which allow us to recommend them as a source of raw materials for the production of pectin. The optimum modes of preliminary washing of raw materials are offered, allowing to the remove the ballast substances as much as possible. It is established that when the drying temperature increases, the destructive processes are catalyzed: the strength of the pectin jelly and the uronide component and the degree of pectin esterification are reduced. The optimum drying temperature of damp apple pomaces is 80 0C, at which the quality of pectin extracted from the dried raw materials is maintained as much as possible. It is shown that the most effective for the pectin production is a fraction with a particle size of 3-5 mm, which allow us to extract up to 71 % of pectin from raw materials.


Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1360
Author(s):  
Ekaterina Budenkova ◽  
Stanislav Sukhikh ◽  
Svetlana Ivanova ◽  
Olga Babich ◽  
Vyacheslav Dolganyuk ◽  
...  

Enzymatic hydrolysis of cellulose-containing raw materials, using Aspergillus niger, were studied. Filter paper, secondary cellulose-containing or starch-containing raw materials, miscanthus cellulose after alkaline or acid pretreatment, and wood chip cellulose, were used as substrates. The study focused on a wild A. niger strain, treated, or not (control), by ultraviolet (UV) irradiations for 45, 60, or 120 min (UV45, UV60, or UV120), or by UV irradiation for 120 min followed by a chemical treatment with NaN3 + ItBr for 30 min or 80 min (UV120 + CH30 or UV120 + CH80). A mixture of all the A. niger strains (MIX) was also tested. A citrate buffer, at 50 mM, wasthe most suitable for enzymatic hydrolysis. As the UV exposure time increased to 2 h, the cellulase activity of the surviving culturewas increased (r = 0.706; p < 0.05). The enzymatic activities of the obtained strains, towards miscanthus cellulose, wood chips, and filter paper, were inferior to those obtained with commercial enzymes (8.6 versus 9.1 IU), in some cases. Under stationary hydrolysis at 37 °C, pH = 4.7, the enzymatic activity of A. niger UV120 + CH30 was 24.9 IU. The enzymatic hydrolysis of secondary raw materials, using treated A. niger strains, was themost effective at 37 °C. Similarly, the most effective treatment of miscanthus cellulose and wood chips occurred at 50 °C. The maximum conversion of cellulose to glucose was observed using miscanthus cellulose (with alkaline pretreatment), and the minimum conversion was observed when using wood chips. The greatest value of cellulase activity was evidenced in the starch-containing raw materials, indicating that A. niger can ferment not only through cellulase activity, but also via an amylolytic one.


2021 ◽  
pp. 87-90
Author(s):  
М.Ж. Кизатова ◽  
Д.А. Абдуллаева

Статья посвящена важности пектиновых веществ, а также расширению сферы использования лекарственного растительного сырья. В качестве лекарственного растительного сырья представлены технологии получения пектинового экстракта из плодов шиповника, которые встречаются на территории Казахстана 25 видов. Применение пектина в медицине. The article is devoted to the importance of pectin substances, as well as to the expansion of the use of medicinal plant raw materials. As a medicinal plant raw material, technologies for obtaining pectin extract from rosehip fruits, which are found in 25 species on the territory of Kazakhstan, are presented. The use of pectin in medicine


2018 ◽  
Vol 33 (2) ◽  
pp. 165-174 ◽  
Author(s):  
Dan Huo ◽  
Qiulin Yang ◽  
Guigan Fang ◽  
Qiujuan Liu ◽  
Chuanling Si ◽  
...  

Abstract Eucalyptus residues from pulp mill were pretreated with aqueous ammonia soaking (AAS) method to improve the efficiency of enzymatic hydrolysis. The optimized condition of AAS was obtained by response surface methodology. Meanwhile, hydrogen peroxide was introduced into the AAS system to modify the AAS pretreatment (AASP). The results showed that a fermentable sugar yield of 64.96 % was obtained when the eucalypt fibers were pretreated at the optimal conditions, with 80 % of ammonia (w/w) for 11 h and keeping the temperature at 90 °C. In further research it was found that the addition of H2O2 to the AAS could improve the pretreatment efficiency. The delignification rate and enzymatic digestibility were increased to 64.49 % and 73.85 %, respectively, with 5 % of hydrogen peroxide being used. FTIR analysis indicated that most syringyl and guaiacyl lignin and a trace amount of xylan were degraded and dissolved during the AAS and AASP pretreatments. The CrI of the raw material was increased after AAS and AASP pretreatments, which was attributed to the removal of amorphous portion. SEM images showed that microfibers were separated and explored from the initial fiber structure after AAS pretreatment, and the AASP method could improve the destructiveness of the fiber surface.


Holzforschung ◽  
2011 ◽  
Vol 65 (4) ◽  
Author(s):  
Fokko Schütt ◽  
Jürgen Puls ◽  
Bodo Saake

Abstract Steam refining was investigated as a pretreatment for enzymatic hydrolysis of poplar wood from a short rotation plantation. The experiments were carried out without debarking to use an economically realistic raw material. Steam refining conditions were varied in the range of 3–30 min and 170–220°C, according to a factorial design created with the software JMP from SAS Institute Inc., Cary, NC, USA. Predicted steaming conditions for highest glucose and xylose yields after enzymatic hydrolysis were at 210°C and 15 min. Control tests under the optimized conditions verified the predicted results. Further pretreatments without bark showed that the enzymes were not significantly inhibited by the bark. The yield of glucose and xylose was 61.9% of theoretical for the experiments with the whole raw material, whereas the yield for the experiments without bark was 63.6%. Alkaline extraction of lignin from the fibers before enzymatic hydrolysis resulted in an increase of glucose yields from mild pretreated fibers and a decrease for severe pretreated fibers. The extracted lignin had a high content of xylose of up to 14% after very mild pretreatments. On the other hand, molecular weights of the extracted lignin increased substantially after pretreatments with a severity factor above 4. Hence, alkaline extraction of the lignin seems only attractive in a narrow range of steaming conditions.


2020 ◽  
pp. 405-414
Author(s):  
Veronika Valentinovna Tarnopol’skaya ◽  
Tat'yana Vasil'yevna Ryazanova ◽  
Natal'ya Yur'yevna Demidenko ◽  
Oksana Nikolayevna Eryomenko

A technology for pilot production of feed products via microbiological conversion of plant raw materials (mixed substrate of pine sawdust and vegetative part of Jerusalem artichoke) by Plerotus ostreatus PO-4.1 and Pleurotus djamor PD-3.2 strains is developed. The technology includes hydrodynamic activation of substrate at the seed stock production stage. The overall technology includes three key stages: submerged fermentation of pure cultures of production strains; submerged-solid phase fermentation of hydrodynamicly activated plant raw materials for seed stock production; solid-state fermentation of mechanically ground plant substrate for feed products production. A successful approbation of submerged-solid state fermentation of production strains on media containing 3% of hydrodynamicly activated raw materials allowed for obtaining seed stock with 14.5 g/l yield of submerged mycelium biomass fully adopted for this type of substrate. Further use of this seed stock biomass at the solid state fermentation stage makes the overall process duration three times shorter compared to existing technologies for direct wood waste bioconversion. The pilot plant results show valuable practicability of plant raw material hydrodynamic activation with the purpose of enhancing its bioaccessibility with consequent increase in degree of microbiological conversion. The product of bioconversion contains 14–16% of protein, biofiber, vitamins and minerals and could be considered for successful use as feed by agricultural enterprises.


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