scholarly journals Production and Properties of Microbial Polyhydroxyalkanoates Synthesized from Hydrolysates of Jerusalem Artichoke Tubers and Vegetative Biomass

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 132
Author(s):  
Tatiana G. Volova ◽  
Evgeniy G. Kiselev ◽  
Alexey V. Demidenko ◽  
Natalia O. Zhila ◽  
Ivan V. Nemtsev ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Average Molecular Weight ◽  
Scale Up ◽  
Jerusalem Artichoke ◽  
Aqueous Extraction ◽  
Carbon Substrate ◽  
Biomass Hydrolysis ◽  
Glucose Ratio ◽  
Vegetative Biomass ◽  
Reducing Substances

One of the major challenges in PHA biotechnology is optimization of biotechnological processes of the entire synthesis, mainly by using new inexpensive carbon substrates. A promising substrate for PHA synthesis may be the sugars extracted from the Jerusalem artichoke. In the present study, hydrolysates of Jerusalem artichoke (JA) tubers and vegetative biomass were produced and used as carbon substrate for PHA synthesis. The hydrolysis procedure (the combination of aqueous extraction and acid hydrolysis, process temperature and duration) influenced the content of reducing substances (RS), monosaccharide contents, and the fructose/glucose ratio. All types of hydrolysates tested as substrates for cultivation of three strains—C. necator B-10646 and R. eutropha B 5786 and B 8562—were suitable for PHA synthesis, producing different biomass concentrations and polymer contents. The most productive process, conducted in 12-L fermenters, was achieved on hydrolysates of JA tubers (X = 66.9 g/L, 82% PHA) and vegetative biomass (55.1 g/L and 62% PHA) produced by aqueous extraction of sugars at 80 °C followed by acid hydrolysis at 60 °C, using the most productive strain, C. necator B-10646. The effects of JA hydrolysates on physicochemical properties of PHAs were studied for the first time. P(3HB) specimens synthesized from the JA hydrolysates, regardless of the source (tubers or vegetative biomass), hydrolysis conditions, and PHA producing strain employed, exhibited the 100–120 °C difference between the Tmelt and Tdegr, prevailing of the crystalline phase over the amorphous one (Cx between 69 and 75%), and variations in weight average molecular weight (409–480) kDa. Supplementation of the culture medium of C. necator B-10646 grown on JA hydrolysates with potassium valerate and ε-caprolactone resulted in the synthesis of P(3HB-co-3HV) and P(3HB-co-4HB) copolymers that had decreased degrees of crystallinity and molecular weights, which influenced the porosity and surface roughness of polymer films prepared from them. The study shows that JA hydrolysates used as carbon source enabled productive synthesis of PHAs, comparable to synthesis from pure sugars. The next step is to scale up PHA synthesis from JA hydrolysates and conduct the feasibility study. The present study contributes to the solution of the critical problem of PHA biotechnology—finding widely available and inexpensive substrates.

Xylitol production from olive-pruning debris by sulphuric acid hydrolysis and fermentation with Candida tropicalis

Holzforschung ◽  
2011 ◽  
Vol 65 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Juan Francisco García Martín ◽  
Sebastián Sánchez ◽  
Vicente Bravo ◽  
Manuel Cuevas ◽  
Luc Rigal ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Sulphuric Acid ◽  
Candida Tropicalis ◽  
Agricultural Waste ◽  
Biomass Productivity ◽  
Specific Substrate ◽  
Substrate Uptake ◽  
Xylitol Production ◽  
Amorphous Cellulose ◽  
Glucose Ratio

AbstractThe debris of olive pruning is a renewable, low-cost and widely available agricultural waste. Its biochemical conversion by hydrolysis and fermentation was undertaken in the present study. Diluted acid hydrolysis was conducted in a heterogeneous stirred tank reactor at 90°C and at a low sulphuric acid concentration (0.0–1.0 N) for 300 min. To increase thed-xylose/d-glucose ratio into the hydrolysate, in another experiment amorphous cellulose and extracts were removed by means of a pretreatment in an extruder with 1 N H2SO4at 70°C before the acid hydrolysis. The fermentation of hydrolysates was performed under microaerobic conditions in a batch bioreactor at 30°C and pH 5 withCandida tropicalisNBRC 0618. The controlled fermentation parameters included maximum specific growth rate, biomass productivity, rate of the specific substrate uptake, rates of specific ethanol and xylitol production, and overall yield of ethanol and xylitol. In the presence of 1.0 N H2SO4, the fermentation of the pretreated hydrolysate led to specific xylitol production rates and overall xylitol yield (0.1 g g-1 h for t=25 h; 0.49 g g-1, respectively) higher than those achieved without pretreatment (0.03 g g-1 h for t=25 h; 0.39 g g-1, respectively). Under these conditions, 53 g xylitol kg-1of dry olive-pruning debris was obtained from the pretreated culture, whereas without pretreatment 70 g ethanol and 34 g xylitol were recovered.

Scale-up of diluted sulfuric acid hydrolysis for producing sugarcane bagasse hemicellulosic hydrolysate (SBHH)

2010 ◽  
Vol 101 (4) ◽  
pp. 1247-1253 ◽  
Author(s):  
Rita de Cássia L.B. Rodrigues ◽  
George J.M. Rocha ◽  
Durval Rodrigues ◽  
Hélcio J.I. Filho ◽  
Maria das Graças A. Felipe ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Hydrolysis ◽  
Sugarcane Bagasse ◽  
Scale Up ◽  
Hemicellulosic Hydrolysate

scholarly journals TECHNOLOGY AND EQUIPMENT FOR PROCESSING ACTIVATED AGRICULTURAL PLANT WASTE INTO BIOETHANOL

2022 ◽  
Vol 16 (4) ◽  
pp. 59-67
Author(s):  
Dmitriy Prosvirnikov ◽  
Denis Tuncev ◽  
Bulat Ziganshin
Keyword(s):  
Enzymatic Hydrolysis ◽  
Acid Hydrolysis ◽  
Wheat Straw ◽  
Raw Materials ◽  
Raw Material ◽  
Pine Wood ◽  
Agricultural Plant ◽  
Plant Waste ◽  
Hydrolysis Temperature ◽  
Reducing Substances

The article is devoted to the development of technology and equipment for the production of bioethanol from agricultural plant waste, activated by the steam explosion method. The value and novelty of research lies in obtaining new data on the effective acidic and enzymatic hydrolysis of activated raw materials, and developing a technology for the conversion of plant raw materials into bioethanol. The studies were carried out on the basis of the Department of Wood Materials Processing of Kazan National Research Technological University (Republic of Tatarstan, Kazan). A pilot plant for the production of bioethanol and the principle of its operation are presented. Pine wood waste and wheat straw (collected in Kukmor region of the Republic of Tatarstan in the period August-September 2021) were used as raw materials. Steam-explosive activation of raw materials was carried out at temperatures of 165 ⁰C and 210 ⁰C for 5 minutes. Acid hydrolysis parameters: H2SO4 concentration - 0.5% and 1.5%, hydromodule 1:15, hydrolysis temperature - 187⁰C, hydrolysis duration - 5 hours. Enzymatic hydrolysis parameters: preparation - Cellulox-A (OOO PO Sibbiopharm, Russia) - 6 and 12 g/kg of raw material, hydrolysis temperature - 45 ⁰C, substrate pH 4.7 (acetate buffer), raw material concentration in the substrate 33 g/l, the duration of hydrolysis is 72 h. Alcoholic fermentation of hydrolysates was carried out at 32-34⁰C using Saccharomyces cerevisiae yeast, fermentation duration 7 h, yeast concentration 25 g/l. The bioethanol yield in % of reducing substances was recalculated after determining the mass yield. It is concluded that the vapor-explosive activation of pine wood at a temperature of 210 ºC makes it possible to obtain by acid hydrolysis and anaerobic fermentation of reducing substances up to 0.26 kg (0.33 l) of ethanol from 1 kg of activated raw materials, and activation of wheat straw at the same temperature allows obtaining up to 0.172 kg (0.218 l) ethanol with 1 kg of activated straw

scholarly journals Ultrasound-Assisted Ultra-Mild-Acid Hydrolisis of -Carrageenan

REAKTOR ◽  
2018 ◽  
Vol 17 (4) ◽  
pp. 191
Author(s):  
Ratnawati Ratnawati ◽  
Nita Indriyani
Keyword(s):  
Molecular Weight ◽  
Acid Hydrolysis ◽  
Average Molecular Weight ◽  
Weight Fraction ◽  
Number Average Molecular Weight ◽  
Hydrolysis Process ◽  
Higher Temperature ◽  
Ultrasound Assisted ◽  
Hydrolysis Of ◽  
Mild Acid

The low molecular weight fraction of κ-carrageenan is useful in biomedical applications. An ultrasound-assisted acid hydrolysis of κ-carrageenan has been studied. κ-carrageenan with an initial number-average molecular weight of 629 kDa was dispersed in distilled water to form a 5 g/l solution. The pH (3 and 6) of the solution was adjusted by adding HCl solution. The depolymerization reaction was carried out in an ultrasonic device at various temperatures (30, 40, 50, and 60°C) and times (8, 16, 24, and 32 min). The experimental results showed that ultrasound positively contributed to acid hydrolysis process. The number-average molecular weight of the treated k-carrageenan was lower or the percentage of reduction was higher at lower pH, longer reaction time, and higher temperature. The lowest number-average molecular weight (14 kDa) or the highest percent of molecular weight reduction reduction (97.7%) was achieved after ultrasonic irradiation at 60°C and pH 3 for 32 min. Keywords: depolymerization; midpoint scission; ultrasonication

scholarly journals Influence of Partial Acid Hydrolysis on Size, Dispersity, Monosaccharide Composition, and Conformation of Linearly-Branched Water-Soluble Polysaccharides

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 2982
Author(s):  
Cristina Lupo ◽  
Samy Boulos ◽  
Laura Nyström
Keyword(s):  
Molecular Weight ◽  
Acid Hydrolysis ◽  
Average Molecular Weight ◽  
Chemical Properties ◽  
Monosaccharide Composition ◽  
Water Soluble ◽  
Partial Hydrolysis ◽  
Composition Analysis ◽  
Hydrolysis Time ◽  
Partial Acid Hydrolysis

The effect of partial acid hydrolysis on the physical and chemical properties of galactomannan, arabinoxylan, and xyloglucan was investigated. Polysaccharides were treated at 50 °C with hydrochloric acid for 3–48 h. Portions of isopropanol (i-PrOH) were added sequentially to the hydrolyzates, resulting in fractions that were collected by centrifugation. As expected, a significant reduction of weight-average molecular weight (Mw) was observed with increasing hydrolysis time. Fractional precipitation was successfully applied to collect at least one polymer fraction with dispersity (Đ) close to one for each polysaccharide. The monosaccharide composition analysis showed that the partial hydrolysis usually lowered the relative amount of side chains, with the exception of galactomannan, where the composition remained largely unaffected. Estimation of the polymer conformation in solution, through evaluation of the Mark-Houwink parameter coefficient (α), confirmed that acid hydrolysis influenced the polysaccharides’ conformation. It was demonstrated that acid treatment in dilute solution followed by fractional isopropanol precipitation is a method, extendible to a variety of polysaccharides, to obtain materials of decreased molecular weight and low dispersity with slightly altered overall composition and conformation.

scholarly journals Formate as an Auxiliary Substrate for Glucose-Limited Cultivation of Penicillium chrysogenum: Impact on Penicillin G Production and Biomass Yield

2007 ◽  
Vol 73 (15) ◽  
pp. 5020-5025 ◽  
Author(s):  
Diana M. Harris ◽  
Zita A. van der Krogt ◽  
Walter M. van Gulik ◽  
Johannes P. van Dijken ◽  
Jack T. Pronk
Keyword(s):  
Penicillium Chrysogenum ◽  
Product Yield ◽  
Penicillin G ◽  
Carbon Substrate ◽  
Molar Ratios ◽  
Formate Oxidation ◽  
System A ◽  
Glucose Ratio ◽  
Biomass Yields ◽  
Substrate Feeding

ABSTRACT Production of β-lactams by the filamentous fungus Penicillium chrysogenum requires a substantial input of ATP. During glucose-limited growth, this ATP is derived from glucose dissimilation, which reduces the product yield on glucose. The present study has investigated whether penicillin G yields on glucose can be enhanced by cofeeding of an auxiliary substrate that acts as an energy source but not as a carbon substrate. As a model system, a high-producing industrial strain of P. chrysogenum was grown in chemostat cultures on mixed substrates containing different molar ratios of formate and glucose. Up to a formate-to-glucose ratio of 4.5 mol·mol−1, an increasing rate of formate oxidation via a cytosolic NAD+-dependent formate dehydrogenase increasingly replaced the dissimilatory flow of glucose. This resulted in increased biomass yields on glucose. Since at these formate-to-glucose ratios the specific penicillin G production rate remained constant, the volumetric productivity increased. Metabolic modeling studies indicated that formate transport in P. chrysogenum does not require an input of free energy. At formate-to-glucose ratios above 4.5 mol·mol−1, the residual formate concentrations in the cultures increased, probably due to kinetic constraints in the formate-oxidizing system. The accumulation of formate coincided with a loss of the coupling between formate oxidation and the production of biomass and penicillin G. These results demonstrate that, in principle, mixed-substrate feeding can be used to increase the yield on a carbon source of assimilatory products such as β-lactams.

Enhancement and Scale-Up of ?-(1, 3) Glucan Production by Agrobacterium sp.

2010 ◽  
Vol 6 (1) ◽  
Author(s):  
Sri Lakshmi Puliga ◽  
Suhas Handa ◽  
Sathyanarayana N Gummadi ◽  
Mukesh Doble
Keyword(s):  
Transfer Rate ◽  
Shake Flask ◽  
Average Molecular Weight ◽  
Scale Up ◽  
Oxygen Transfer Rate ◽  
Fed Batch ◽  
Batch Mode ◽  
Initial Ph ◽  
Effects Of Ph ◽  
Curdlan Production

Curdlan is a water insoluble polysaccharide composed exclusively of ?-(1, 3) linked glucose residues. Agrobacterium sp. is known to produce extracellular curdlan under nitrogen-limited conditions. The purpose of this study was to investigate the effects of pH, amounts of ammonium, sucrose and trace elements, and time the addition of sucrose, ammonium and uracil on the production of curdlan in a shake flask and to further scale-up the process to a 5 L fermentor. A maximum of 48.7 g L-1 of curdlan was obtained in a shake flask when 150 and 1.4 g L-1 of sucrose and ammonium were used at the initial pH of 6.5. The production was enhanced to 57 g L-1 by adding one third of sucrose and 1 g L-1 of uracil at the 48th h in a fed batch mode. The process was scaled up to a 5 L bioreactor in a batch mode where the oxygen transfer rate was higher (0.192 mg L-1s-1) when compared to that in the shake flask (0.096 mg L-1s-1). Curdlan production was 58 g L-1 in the bioreactor, which was higher than the shake flask under batch conditions (48.7 g L-1). The viscosity average molecular weight of the curdlan produced was found to be 1.4 × 105.

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