In course of searching for proteolytic microbes from the gut of Gryllotalpa africana, a potent isolate GAP 12.4 was screened and identified as Kitasatospora cheerisanensis having protease activity 46.8 ± 1.52 U/ml. Optimum conditions for the protease production (605.3 ± 9.7 U/ml) were 7-d cultivation, 5% inoculum, pH 9.5, 55 °C, 150 rpm, and supplementation with 0.8% glucose and 0.6% ammonium sulfate. Surfactants such as SDS, EDTA, Tween 80 and Triton X-100 showed positive effect on enzyme production. Addition of biotin (50 μg/ml) promotes enzyme production maximally (674.15 ± 4.13 U/ml). Further enhancement on addition of casein hydrolysate and molasses to the production medium was 709.20 ± 7.53 U/ml and 744.26 ± 9.71 U/ml, respectively. The isolate was also able to utilize agro-industries waste, green gram husk in solid-state fermentation for enzyme production (1675.02 ± 21.58 U/ml). This thermo-alkaliphilic isolate may be a potent candidate for low cost protease production through management of agro-residues. It is the first report of protease production by a member of actinobacteria under the Kitasatospora genus.

Nowadays, levan synthesis and its biocatalysis is a step claiming attention due to its promising uses in biomedical field. Levansucrase, as the enzyme responsible of levan biocatalysis is studied in this work concerning sequence homology, signal peptide, metal binding, etc. More than 650 different levansucrase sequences were studied and many interesting results were obtained such as phylogenetic trees and conserved residues that could be essential for biocatalysis machinery. Moreover, a review of levan applications in biomedicine and health field was made. It is showed the advances in applications such as a film agent, a carrier for drug delivery systems, an anti-inflammatory compound or its potential use for functional food as prebiotic.

Here, we studied the modification of fibres derived from the fruit juice industry to prepare new value-added ingredients. These by-products are usually composted or used as animal feed. In this regard, fibres from apple, peach and citrus fruit were enzymatically treated to improve their functional properties, with the aim to use them as food ingredients. Several enzymes were selected to modify various parts of the polymers present in the fibres. The effect of the treatments was assessed by comparing the water-holding capacity (WHC) and swelling water capacity (SWC) of the modified and raw fibres. Fourier transform infrared (FTIR) spectrometry was also used to monitor changes in fibre structure. After the enzymatic modifications, some of these fibres not only showed an increase in WHC and SWC compared with the starting material but also greater viscosity.

A dye-decolorizing bacterium was isolated from a coconut coir sample and identified as a new genus Kerstersia sp. by various biochemical tests and 16S rRNA gene sequencing. This bacterium was capable of degrading sulfonated azo dye Amaranth aerobically at 40 °C and pH 7.0. Tests conducted on intracellular crude enzyme extract identified an oxygen insensitive azoreductase. The optimum dye-decolorizing activity at pH 7.0 and 40 °C for the decolorization of dye was 0.091 U mL−1 (μmax 0.522 mg h−1). The Ks 104.51 μM−1 has been evaluated by plotting Lineweaver–Burk plot for the Amaranth dye. The dye degraded products were extracted and characterized by TLC, diazotization and Carbylamines test, which indicated that Amaranth was biotransformed into non-toxic aromatic metabolite without amine group.

Ascorbyl fatty acid esters are commercially interesting fat-soluble antioxidants. In this work, enzymatic synthesis of ascorbyl esters from less expensive and readily available plant oils, and their anti-oxidative activities are described. Among the immobilized lipases tested, Candida antarctica lipase B was the best for the synthesis of plant oil-based ascorbyl esters. The enzyme showed much better catalytic performances in the binary mixtures of biomass-based 2-methyltetrahydrofuran (MeTHF) and t-butanol than the previously preferred t-butanol. The conversions of 70–73% were obtained under the optimal reaction conditions after 24 h, with the unsaturated fatty acid esters (oleate and linoleate, 80–90%) as the major products. The immobilized lipase kept the relative activity of 80% after reuse for 6 batches in MeTHF-containing system. Besides, anti-oxidative activities of plant oil-based ascorbyl esters and ascorbic acid were comparable, which could remove α,α-diphenyl-β-picrylhydrazyl (DPPH) free radical of >87%.

Microbial hydroxylation of 17β-estradiol (1) with Penicillium brevicompactum, a fungal species not used in biotransformation so far, yielded four metabolites: 1, 3, 5-estratriene-3, 15α-diol-17-one (2); 1, 3, 5-estratriene-3, 6α, 17β-triol (3); 1, 3, 5-estratriene-3, 15α, 17β-triol (4); and 1, 3, 5-estratriene-3, 6α, 15α-triol-17-one (5). All the products were determined by 1H NMR, 13C NMR, two-dimensional NMR, and HRMS techniques. Compounds 3, 4, and 5 are reported for the first time via microbial transformation, and 5 is a new compound as far as we know. Possible metabolic pathway of 17β-estradiol via Penicillium brevicompactum was also proposed.

The objective in the present study was to evaluate α-amylase production by Bacillus amyloliquefaciens ATCC 23350 in submerged culture using untreated macauba cake and peach palm flour as substrates. The cultures were shaken at 120 rpm, 30 °C for 36 h. The effects of pH and weight/volume ratio (W/V) on the α-amylase activity were investigated using response surface methodology (RSM). Protease production was also evaluated. The maximum activity was obtained after 24 h under process conditions adjusted to 1/12 of W/V and pH 7.0 for both substrates. The process that utilized peach palm flour exhibited a much higher α-amylase activity (3330.6 UmL−1) than for macauba cake (196.0 UmL−1).

Extracellular Yarrowia lipolytica lipase Lip2 (YLIP2) demonstrated an (R)-enantiopreference for efficient resolution of (R,S)-1-phenylethanol by solvent engineering with different kinds of binary solvent. The enantioselectivity was significantly improved by the addition of 1, 4-dioxane. The reaction parameters including co-solvent concentration, reaction temperature, and the reaction time were optimized. When the reaction was carried out with n-hexane in the presence of 0.8% 1,4-dioxane at 50°C for 72 h, the enantiomeric excess of product markedly increased to 99.1% from 66% in pure n-hexane; the enantiomeric ratio was higher than 200, which was 500-fold compared with that in pure n-hexane. The results indicated that it is very important to design the proper co-solvents, especially to create appropriate micro-environment for YLIP2 for catalyzing the resolution of (R,S)-1-phenylethanol.

We report the optimization of production of a halotolerant, thermoalkaline protease by Bacillus cereus SIU1, at shake-flask and bench-scale bioreactor level, using conventional and response surface methods. The basal medium supplemented with optimized (w/v) 0.8% glucose, 1.5% peptone, and 0.4% yeast extract produced 224 Uml− 1 alkaline protease after 20 h incubation. Enzyme yield was further increased to 491 Uml− 1 when the fermentation broth was supplemented with 0.02% (w/v) Ca2+. Optimization of physical factors resulted in still higher protease level of 651 Uml− 1 within 18 h fermentation at initial pH 9.0, 50°C, and 150 rpm agitation. Statistically designed experiments revealed significant effects of peptone and CaCl2 on protease production. A maximum of 749 protease Uml− 1 was produced at optimum factor levels (w/v) of peptone 1.75%, yeast extract 0.4%, CaCl2 0.025%, and pH 9.0 after 18 h incubation. Optimization of agitation and aeration rates in bench-scale bioreactors further enhanced the enzyme yield to 941 protease Uml− 1 at 125 rpm and 2.0 vvm aeration. Optimization of protease production by conventional and statistical approaches resulted in a ∼10.7-fold increase (941 Uml− 1) compared to un-optimized conditions (88 Uml− 1).