Response surface methodological approach to optimize the nutritional parameters for enhanced production of -amylase in solid state fermentation by Thermomyces lanuginosus

Response surface methodology was used to study the cumulative effect of the nutritional parameters and to enhance the production of extracellular -amylase in solid-state ermentation by Thermomyces lanuginosus ATCC 58157. These nutritional parameters considered include carbon source (soluble starch), nitrogen source (peptone) and a concentrated mineral medium. For obtaining the mutual interaction between the variables and optimizing these variables, a 23 factorial central composite design using response surface methodology was employed. The optimal calculated values of tested variables for maximal production of -amylase were: soluble starch, 71.10 g/Kg peptone, 91.97 g/Kg and mineral salts solution, 175.05 ml/Kg with a predicted -amylas activity of 5.085 ´ 105 U/Kg of wheat bran. These predicted optimal parameters were tested in the laboratory and the final -amylase activity obtained, 4.94 ´ 105 U/Kg of wheat bran, was very close to the predicted value.African Journal of Biotechnology Vol. 4 (7), pp. 708-716, 200

Degradation of pulp and paper-mill effluent by thermophilic micro-organisms using batch systems

Paper manufacturers produce large quantities of wastewater, which can have deleterious effects on the receiving waters; therefore there is a need to find a treatment process which can minimize these effects considerably. A suitable aerobic biological treatment process that can be used with great success involves the use of thermophilic micro-organisms. This technology has many advantages, which include rapid biodegradation rates, low sludge yields, and excellent process stability. Batch studies were conducted on two types of activated sludge (pulp-mill sludge and sewage sludge) at 40°C, 50°C and 60°C to determine the feasibility of thermophilic degradation of bleach pulp-mill effluent in terms of increasing aeration, biomass concentration and nutrient addition. Preliminary batch studies had confirmed the feasibility of thermophilic degradation, as COD removal achieved with the pulp-mill sludge was 55.2%, 37.6% and 31.4% at 40°C, 50°C and 60°C after 5d, respectively while the COD removal with sewage sludge was 50.2%, 37.3% and 27% under the same conditions. Degradation was further improved, using the same inocula in subsequent experiments and this confirmed that an acclimatization period is required, prior to degrading the bleach pulp-mill effluent. Thermophilic degradation of pulp-mill effluent occurs at temperatures of up to 60°C; however, once final degradation is obtained, it decreases significantly as temperature increases. Keywords: thermophilic micro-organisms, pulp and paper mill effluent, degradation, batch systems Water SA Vol. 31(4) 2005: 575-58

Engineering and Applications of fungal laccases for organic synthesis

Laccases are multi-copper containing oxidases (EC 1.10.3.2), widely distributed in fungi, higher plants and bacteria. Laccase catalyses the oxidation of phenols, polyphenols and anilines by one-electron abstraction, with the concomitant reduction of oxygen to water in a four-electron transfer process. In the presence of small redox mediators, laccase offers a broader repertory of oxidations including non-phenolic substrates. Hence, fungal laccases are considered as ideal green catalysts of great biotechnological impact due to their few requirements (they only require air, and they produce water as the only by-product) and their broad substrate specificity, including direct bioelectrocatalysis

Enzymatic modification for ascorbic acid and alpha-tocopherol to enhance their stability in food and nutritional applications

Antioxidants protect cells against the effects of harmful free radicals and play an important role in preventing many human diseases (e.g. cancer, atherosclerosis, neurodegeneration, inflammatory disorders, etc.) and aging itself. In addition, antioxidant molecules are employed to prevent unsaturated oil products from becoming rancid during storage and thus extend oil life. The modification –chemical or enzymatic- of natural antioxidants in order to increase their miscibility and/or stability towards the action of light and/or oxygen renders a series of “semisynthetic” antioxidants with great impact in the food and feed industries. In this review, we will discuss the enzymatic modifications of antioxidant vitamins C and E. L-Ascorbic acid (vitamin C) is the major water-soluble natural antioxidant acting as a free radical scavenger, and plays an important role in regenerating vitamin E. However, due to the low miscibility of ascorbic acid with -tocopherol, it is necessary to use ascorbyl fatty acid derivatives. Thus, esters of L-ascorbic acid with long-chain fatty acids (esp. palmitic or stearic) are employed as additives in foods (E-304) rich in lipids. The enzymatic synthesis of acyl L-ascorbates offers some advantages compared with the current chemical process, such as its high regioselectivity and the moderate reaction conditions. Vitamin E enhances the oxidative stability of polyunsaturated fatty acids from peroxidation acting as a free radical scavenger and is generally administered in the form of all-rac-α-tocopheryl acetate or succinate to increase its stability. Several approaches have been described for the enzyme-catalysed synthesis of vitamin E acetate, based on the transesterification of vinyl acetate with vitamin E, or the regioselective hydrolysis of -isophorone followed by reaction with isophytol. The above vitamin C and E derivatives may have impact not only as food preservatives but also as components of functional foods.We thank Ana V. Ugidos and Soledad Peña (Biotecnologías Aplicadas, BTSA, Spain) for technical information and suggestions. This research was supported by the Spanish CSIC (Project 200680F0132), Spanish MEC (Projects BIO2002-00337 and BIO2007-67708-C04-01) and European Union (Project MIF1-CT-2006-040163). Spanish MEC and Comunidad de Madrid are also thanked for fellowships to Dr. A. Kunamneni (SB2004-0011) and P. Torres, respectively.Peer reviewe

Antiviral Drugs and Vaccines for Omicron Variant: A Focused Review

The Omicron variant of concern (VOC) replaced the delta variant rapidly and became the predominant strain due to more mutations in spike protein and receptor-binding domain (RBD) enhancing its infectivity and binding affinity. The severity of the illness is less than that of the delta variant. Omicron is nonsusceptible to REGEN-COV™ and bamlanivimab with etesevimab. Drugs that are effective against the Omicron variant are oral antiviral drugs such as Paxlovid (nirmatrelvir/ritonavir), remdesivir, sotrovimab, and molnupiravir. The potency of sotrovimab is reduced to 3-fold against Omicron, and 8-fold reduction in potency with sotrovimab is found in a particular variant of Omicron with a R346K substitution in spike protein. There are neither clinical trials comparing the efficacy of these 4 therapies with each other nor any data on a combination of two or more therapies. The current recommendation for mild-moderate, nonhospitalized patients who are at a high risk of disease progression is to use Paxlovid as the first-line option. If Paxlovid is not available or cannot be administered due to drug interactions, then the next best choice is sotrovimab. The third choice is remdesivir if sotrovimab is also not available and molnupiravir is to be given if the other three options are not available or cannot be administered. For prevention, 2130 (cilgavimab) in combination with COV2-2196 (tixagevimab) has been effective against BA.2 only. LY-CoV1404 (bebtelovimab) is recently authorized as it is effective against all sublineages of the Omicron variant. Regarding vaccine efficacy (VE), the 3-dose VE with mRNA vaccines at 14–60 days was found to be 71.6%, and after 60 days, it is 47.4%. There is a 34–38-fold reduction of neutralizing activity with prebooster sera and a 19-fold reduction with booster sera for the Omicron variant. This probably explains the reason for worldwide breakthrough infections with the Omicron variant with waning immunity. The neutralizing antibody response against Omicron elicited by the bivalent vaccine is superior to that of the ancestral Wuhan strain, without any safety concerns. For future advances, the ribosome display technology can be applied for the generation of human single-chain fragment variable (scFv) antibodies from B cells of recovered patients against Omicron and other Coronavirus variants as they are easier and faster to produce and have high affinity and high specificity

Laccases and Their Applications: A Patent Review

Abstract: Laccases are an interesting group of multi copper enzymes, which have received much attention of researchers in last decades due to their ability to oxidize both phenolic and non-phenolic lignin related compounds as well as highly recalcitrant environmental pollutants. This makes these biocatalysts very useful for their application in several biotechnological processes. Such applications include the detoxification of industrial effluents, mostly from the paper and pulp, textile and petrochemical industries, polymer synthesis, bioremediation of contaminated soils, wine and beverage stabilization. Laccases are also used as catalysts for the manufacture of anticancer drugs and even as ingredients in cosmetics. Recently, the utility of laccases has also been applied to nanobiotechnology. This paper reviews recent and important patents related to the properties, heterologous production, molecular cloning, and applications of laccases within different industrial fields as well as their potential extension to the nanobiotechnology area

Ribosome display for the rapid generation of high-affinity Zika-neutralizing single-chain antibodies.

BACKGROUND:Zika virus (ZIKV) is an emerging pathogen with no approved therapeutics and only limited diagnostics available. To address this gap, six mouse single-chain antibodies (scFvs) to ZIKV envelope (E) protein were isolated rapidly and efficiently from a ribosome-displayed antibody library constructed from the spleens of five immunized mice. METHODOLOGY/RESULTS:In this report, we have generated a panel of mouse scFvs to ZIKV E protein using ribosome display. The six scFvs demonstrated no cross-reactivity with DENV2 NGC envelope protein, suggesting specificity for ZIKV E protein. These scFvs showed differences in their affinity: two (scFv45-3, scFv63-1) of them were dominant after four rounds of panning, and showed higher affinity (an apparent Kd values from 19 to 27 nM) than the other four (scFv5-1, scFv7-2, scFv38-1, and scFv51-2). All six scFvs showed ZIKV-neutralizing activity in the plaque reduction neutralization test (PRNT) assay and their neutralizing activity was positively correlated with their affinities. CONCLUSIONS/SIGNIFICANCE:The scFvs (45-3 and 63-1) with highest affinity may have dual utility as diagnostics capable of recognizing ZIKV E subtypes and may be further developed to treat ZIKV infection. Our approach has the added advantage of generating Fc receptor-deficient antibodies, minimizing concern of antibody-dependent enhancement (ADE) of infection