aqueous extraction
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2022 ◽  
Author(s):  
Gabriella Masaki ◽  
Filiana Santoso ◽  
Maria D.P.T. Gunawan Puteri
Keyword(s):  

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 132
Author(s):  
Tatiana G. Volova ◽  
Evgeniy G. Kiselev ◽  
Alexey V. Demidenko ◽  
Natalia O. Zhila ◽  
Ivan V. Nemtsev ◽  
...  

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.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Juma N. Daniels ◽  
Andrew Otte

Background/Objective: Ketamine, a psychedelic, is a noncompetitive N-methyl-D-aspartate receptor antagonist that may also bind to mu opioid receptors.  Historically, it has been used as an anesthetic (KetalarÒ), although now has found uses as a novel, quick acting, antidepressant for treatment-resistant depression (SpravatorÒ) and could be used as an adjuvant to opioid analgesia providing opioid-sparing effects.  One major advantage over opioids is Ketamine does not suffer from respiratory depression and maintains patent airways during anesthesia.  Ketamine is only available as a short-acting injectable solution or a nasal spray. Our goal is to develop a long-acting injectable form in a biodegradable matrix poly(lactic-co-glycolic) acid (PLGA) that does not have a burst release and provides 5-7 days of steady-state plasma levels.  Methods: A mechanistic approach towards development of a long-acting injectable began with a solubility screen of Ketamine. Based on these results, experiments began with an oil in water emulsification with two theoretical drug loadings (25% and 40%) and two processing conditions – (1) aqueous extraction and (2) aqueous extraction, intermediate drying, and a 25% Ethanol wash.  The formulations were characterized for drug loading, drug release, and crystallinity and imaged using scanning electron microscopy (SEM).  Results: Minimal differences were noted in the release profiles between formulations. Although, a significant difference was noted between the two processing conditions, where the extra intermediate drying step and 25% ethanol wash resulted in a significant slowing of the drug release rate.  Conclusion and Implications: The difference in release kinetics is hypothesized to be due to densification of the PLGA matrix, based on the increase in surface roughness/wrinkling in the SEM images, crystallinity increase, and on their respective powder x-ray diffraction patterns.  Our preliminary results demonstrate the feasibility of a longer acting Ketamine using PLGA. Further refinement of these formulations and rodent pharmacokinetic studies will be done in future.


Author(s):  
Gabriela G. López ◽  
María M. Brousse ◽  
María L. Vergara ◽  
Adriana M. Gonzalez ◽  
Nancy E. Cruz ◽  
...  

In this study, the kinetics of aqueous extraction of phenolic compounds from the yerba mate leaves were analyzed. A temperature range between 40°C and 70°C and a ratio of 25 g of mate leaves in 200 mL of water were used. The extraction kinetic was studied adjustment of the kinetics models of first order, second order kinetic model and the second order diffusive model. The goodness of the fit was controlled by the magnitude of the coefficient of determination (R2), the percentage error (EP %) and the square root of the mean square error (RMSE).The second order kinetic models adequately described the extraction process, achieving the best fit with the second order diffusive model (EP%= 0,81 to 2,9; EP%= 11,24 to 14,99 and 4,72 and 6,92) that provided important information about the initial extraction process and the mechanism that occurs in the final extraction stage. The temperature influenced the kinetic parameters; however, the final equilibrium concentration of phenolic compounds was not affected by it. The results of this study allow us to obtain better overall knowledge of the times and temperatures for improved extraction rates and energy consumption for the industrialization of these compounds.


2021 ◽  
pp. 115-118
Author(s):  
Lighty George ◽  
C. Padmalatha ◽  
A. J. A. Ranjitsingh ◽  
P. Dhasarathan

2021 ◽  
Vol 914 (1) ◽  
pp. 012064
Author(s):  
N Wahyuni ◽  
S D Riendriasari

Abstract Today’s stingless bees are in great demand by beekeepers in Lombok. Besides producing honey, it also produces propolis which has more value. Propolis or bee glue is a substance produced by honey bees collected from the top young leaves mixed with the saliva, patch, and hive sterilization. This substance could be used for antibacterial, antivirus, antifungal, and anti-protozoa. In Lombok, apiculture for stingless bees has spread in almost every district. Northern Lombok, West Lombok, and East Lombok were the first three locations that developed stingless bees. This study aimed to identify the species of stingless bees and their propolis productivity and characteristics produced by each species. There were two species of stingless bees cultivated by the people of Lombok, Trigona clypearis and Trigona sapiens. The development of science, genus Trigona changed nomenclature into Tetragonula. The yield of propolis through extraction using water or Aqueous Extraction Propolis (AEP) produced by T. clypearis was 34-55% and T. sapiens was in the range of 3-24%. The flavonoid content equivalent to quercetin in propolis produced by T. sapiens as vary as T. clypearis. The results of this study could be used as a baseline for other propolis extraction activities to produce propolis more marketable.


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