Nanotechnology is an area that has been growing over the years, being possible nowadays to find numerous materials constructed at nanoscale. In addition, many applications have been attributed to ...these "new" materials. In this review is presented a brief overview of nanoparticles used for the immobilization of enzymes. Considering the extensive universe of immobilization in nanoparticles, some were chosen to be exposed here, such as chitosan, graphene, silica, polymers, magnetic, nanoflowers, among others. Advantages, disadvantages and limitations of nanoimmobilization also be discussed. Some applications of nanoimmobilized enzymes are presented, like as biodiesel, flavor synthesis ester and biosensors. The purpose of this paper is to provide an overview of what is being studied in relation to nanoparticles for enzymes immobilization, and some discussions about them, aimed at assisting researchers in future studies and reviews.
Advantages, drawbacks and trends in nanomaterials for enzyme immobilization.
Polyhydroxyalkanoates are biodegradable polymers produced by prokaryotic organisms from renewable resources. The production of PHAs by submerged fermentation processes has been intensively studied ...over the last 30
years. In recent years, alternative strategies have been proposed, such as the use of solid-state fermentation or the production of PHAs in transgenic plants. This paper gives an overview of submerged and solid-state fermentation processes used to produce PHAs from waste materials and by-products. The use of these low-cost raw materials has the potential to reduce PHA production costs, because the raw material costs contribute a significant part of production costs in traditional PHA production processes.
•Bioprocess design and costing for 2,3-butanediol production.•Versatile downstream separation of 2,3-butanediol by reactive extraction.•The composition of fermentation media affects the cost of ...2,3-butanediol production.•The prospects of bio-based 2,3-butanediol production is promising.
This study presents the techno-economic evaluation of 2,3-butanediol (BDO) production via fermentation using glycerol, sucrose and sugarcane molasses as carbon sources. Literature-cited experimental data were used to design the fermentation stage, whereas downstream separation of BDO was based on reactive extraction of BDO employing an aldehyde to convert BDO into an acetal that is immiscible with water. The selected downstream process can be used in all fermentations employed. Sensitivity analysis was carried out targeting the estimation of the minimum selling price (MSP) of BDO at different plant capacities and raw material purchase costs. In all cases, the MSP of BDO is higher than 1$/kg that is considered as the target in order to characterize a fermentation product as platform chemical. The complex nutrient supplements, the raw material market price and the fermentation efficiency were identified as the major reasons for the relatively high MSP observed.
Pseudomonas aeruginosa produces abundant levels of rhamnolipid biosurfactants which exhibit remarkable chemical and physical characteristics, making these compounds attractive targets for ...biotechnology research. The complex gene regulation network involved in rhamnolipids’ biosynthesis represents a challenge to industrial production, which has been the object of a growing number of studies. This article provides a comprehensive review of the known gene regulatory factors involved in rhamnolipid production within P. aeruginosa. The regulatory factors include quorum sensing systems proteins and environmental response, and global regulatory systems within basal bacterial physiology, acting either at transcriptional or post-transcriptional level. The multilayer gene regulation responds to a wide variety of environmental and physiologic signals, and is capable of combining different signals in unique and specific responses.
The production of a lipase by a wild-type Brazilian strain of
Penicillium simplicissimum in solid-state fermentation of babassu cake, an abundant residue of the oil industry, was studied. The enzyme ...production reached about 90
U/g in 72
h, with a specific activity of 4.5
U/mg of total proteins. The crude lipase showed high activities at 35–60
°C and pH 4.0–6.0, with a maximum activity at 50
°C and pH 4.0–5.0. Enzyme stability was enhanced at pH 5.0 and 6.0, with a maximum half-life of 5.02
h at 50
°C and pH 5.0. Thus, this lipase shows a thermophilic and thermostable behavior, what is not common among lipases from mesophilic filamentous fungi. The crude enzyme catalysed the hydrolysis of triglycerides and
p-nitrophenyl esters (C4:0–C18:0), preferably acting on substrates with medium-chain fatty acids. This non-purified lipase in addition to interesting properties showed a reduced production cost making feasible its applicability in many fields.
•Lipase immobilization rate on octyl supports is reduced at high ionic strength.•Octyl-lipase is more rapidly inhibited by D-pNPP than covalent preparations.•Octyl-lipase inhibition by D-pNPP did not ...depend on ionic strength.•Octyl-lipase activity is less depended on ionic strength.•Lipase activity is not only depended on catalytic Ser exposition.
The lipases from Thermomyces lanuginosus and Pseudomonas cepacia have been immobilized on octyl and cyanogen bromide (CNBr) agarose beads. The immobilization on octyl-agarose is slowed with increasing ionic strength, while the immobilization on CNBr is not significantly affected by the ionic strength. The inhibition of the immobilized preparations with diethyl p-nitrophenylphosphate (D-pNPP) was analyzed. The inhibition was more rapid using octyl-lipase preparations than using covalent preparations, and the covalent preparations were much more sensitive to the reaction medium. The addition of detergent increased the inhibition rate of the covalent preparation while an increase on the ionic strength produced a slowdown of the inhibition rate by D-pNPP for both lipases. The effect of the medium on the activity versus fully soluble substrate (methyl mandelate) was in the same direction. The octyl preparations presented a slight decrease in activity when comparing the results using different concentrations of sodium phosphate buffer (between 0.025 and 1M), while the CNBr preparations suffered drastic drops in its activity at high ionic strength.
The results confirm that the lipases immobilized on octyl agarose presented their open form stabilized while the covalent preparation maintains a closing/opening equilibrium that may be modulated by altering the medium.
The present study aimed to identify novel microbial producers of bioemulsificant compounds from Antarctic soils. Fifty-nine microbial strains were isolated from five different locations at South ...Shetland Islands, Antarctica, and screened for biosurfactant production by β-hemolytic activity. Strain So 3.2 was determined as bioemulsifier-producer and identified by phenotypic and molecular characterization as Streptomyces luridus. Emulsification activity, oil displacement method and drop-collapsing test were performed to evaluate the biosurfactant activity with different oils and hydrocarbons using two different culture media (Luria Bertani and Bushnell Haas in the presence of different carbon sources: glucose, glycerol, olive oil and n-Hexadecane). Cell free supernatant of Bushnell Haas culture supplemented with n-Hexadecane showed the best results for all tests. Emulsification of hydrocarbons exceeded 60%, reaching up to 90% on oil with high API grade, while displacement tests ranged from 8 cm to 4 cm in diameter according the culture media and tested oils. Our results revealed that Streptomyces luridus So3.2 is able to produce bioemulsifiers capable of emulsifying hydrocarbons and oils, which could be used in different biotechnological applications, particularly for bioremediation of environments contaminated by oil leaks.
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•Lipase extract from C. rugosa was found very useful to produce biolubricants from soybean oil.•The free lipase cannot be used at medium scale.•The immobilization in Accurel enabled ...the reaction maintaining the good properties of the enzyme.•The immobilized lipase could be reused several reaction cycles.
Three commercial lipases, Lipomod 34MDP (free lipase from Candida rugosa), Lipozyme RM IM (immobilized lipase from Rhizomucor miehei) and Novozym 435 (immobilized lipase B from Candida antarctica) were evaluated as catalysts in the production of biolubricant base oils. This was accomplished via the esterification of free fatty acids obtained from soybean-oil hydrolysis and different polyols (neopentyl glycol, NPG; trimethylolpropane, TMP; and pentaerythritol, PE). Reactions carried out with free C. rugosa lipase showed the highest conversions for the three polyols (97% for NPG, 100% for TMP and 55% for PE) after 24 h, while Novozym 435 and Lipozyme RM IM resulted, respectively, in 65% and 92% for NPG, 15% and 39% for TMP and 1% and 0% for PE. Then, Accurel MP1000 (a microporous polypropylene support, PP) was used to immobilize the C. rugosa lipase; enzyme loading used was 0.3 mg/g. The zymography analysis showed that the protein band of 60 KDa present in the C. rugosa lipase extract was the main protein responsible for the extract activity in the biolubricant synthesis and it was successfully immobilized onto the support. The immobilized lipase (34MDP-PP) showed conversions of 99% for NPG and 92% for TMP, after 24 h of reaction, maintaining the results obtained with the free enzyme. The 34MDP-PP could be reused for six consecutive reaction cycles without a reduction in the final conversion, using NPG and TMP as substrates. Using Lipozyme RM IM, the conversion decreased from 92 to 56% after six consecutive reactions. The soybean esters of NPG and TMP showed good viscosity indexes, higher than 200.
•Lipase PS has been immobilized on Accurel in less than 1h with a 70% increase in activity.•Irreversible inhibition with D-pNPP suggested the involvement of the open form of the lipase in the ...immobilization process.•The new biocatalyst is much more active that the commercial one in hydrolysis and synthetic reactions.•The resolution of (±)-1,3,4-tri-O-benzyl-myo-inositol (1) has been optimized using RSM.•The new biocatalyst is more efficient in kinetic resolution of 1 than Novozym 435.
Lipase from Burkholderia cepacia (PS) has been immobilized on Accurel MP 1000, and their performance has been compared to that of the most widely used immobilized commercial preparation of this enzyme. The maximum loading was 18mgprotein/g support, and its thermal and solvent stability was much higher than that of the commercial. PS preparations were used in hydrolysis of triacetin and methyl mandelate, in the esterification of oleic acid and ethanol and in the kinetic resolution of 1,3,4-tri-O-benzyl-myo-inositol (DL-1) using vinylacetate as activated acyl donor. For all reactions studied, PS on Accurel was more active than PS-IM. The conversion in the kinetic resolution of racemic DL-1 was optimized using response surface methodology. Optimal conditions were determined to be 2.0mg/mL of substrate, temperature of 40°C, 2.0mL of vinyl acetate and without water addition. Under these conditions, maximum loaded Accurel-PS preparation permitted to improve the activity in this kinetic resolution compared to the PS commercial preparation by a 55-fold factor, and compared to Novozym 435 (the most active described in literature for this reaction) by a 23-fold factor. The conversion attained was 49.9%±0.3 of conversion and ee of 99% after 24h. The reusability studies showed maintenance of conversion and ee during eight cycles.
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