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10 pages, 1017 KiB

Open AccessArticle

Quantification of Neoagaro-Oligosaccharide Production through Enzymatic Hydrolysis and Its Anti-Oxidant Activities

by Shu-Ying Xu, Jie Kan, Zhong Hu, Yang Liu, Hong Du, Guang-Chang Pang and Kit-Leong Cheong

Molecules 2018, 23(6), 1354; https://doi.org/10.3390/molecules23061354 - 05 Jun 2018

Cited by 46 | Viewed by 4413

Neoagaro-oligosaccharides (NAOS) have health benefits that are related to their amount and degree of polymerization (DP). However, the current methods that are used to quantify enzymatically released NAOS are un-specific and time-consuming. Agar has been extracted from Gelidium amansii and has been degraded [...] Read more.

Neoagaro-oligosaccharides (NAOS) have health benefits that are related to their amount and degree of polymerization (DP). However, the current methods that are used to quantify enzymatically released NAOS are un-specific and time-consuming. Agar has been extracted from Gelidium amansii and has been degraded by AgaXa (a recombinant β-agarase). Polysaccharide analysis using carbohydrate gel electrophoresis (PACE) has been adapted in order to quantify NAOS. In addition, the anti-oxidant activity of the degraded samples has been assessed. We have found that the PACE method provided sensitive, precise, and accurate quantification for each of the six NAOS samples. PACE has revealed that the DP of the enzymatic products from the AgaXa digestion were mainly neoagaro-octaose and neoagaro-decaose. The degraded samples exhibited increased radical-scavenging activity towards 2,2-diphenyl-1-picrylhydrazyl and 2,2-azino-bis(3-ethylbenzothiazoline sulfonic acid) radicals. While the anti-oxidant activity may have been from NAOS activity and contributions from neoagaro-octaose and neoagaro-decaose. The adapted PACE method that has been presented here is promising for large sample analysis during quality control and for characterizing novel β-agarase degradation mechanisms. Full article

(This article belongs to the Special Issue Selected Papers from the 6th International Conference on Biotechnology and Bioengineering (6-ICBB 2017))

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12 pages, 12104 KiB

Open AccessArticle

The Detailed Bactericidal Process of Ferric Oxide Nanoparticles on E. coli

by Yunqiao Li, Dong Yang, Shang Wang, Chenyu Li, Bin Xue, Lin Yang, Zhiqiang Shen, Min Jin, Jingfeng Wang and Zhigang Qiu

Molecules 2018, 23(3), 606; https://doi.org/10.3390/molecules23030606 - 08 Mar 2018

Cited by 38 | Viewed by 4908

Abstract

While nanoparticles exert bactericidal effects through the generation of reactive oxygen species (ROS), the processes of the internalization of and the direct physical damage caused by iron oxide nanoparticles are not completely clear. We hypothesize that direct physical or mechanical damage of the [...] Read more.

While nanoparticles exert bactericidal effects through the generation of reactive oxygen species (ROS), the processes of the internalization of and the direct physical damage caused by iron oxide nanoparticles are not completely clear. We hypothesize that direct physical or mechanical damage of the cell membrane and cytoplasmic integrity by nanoparticles is another major cause of bacterial death besides ROS. The aim of this study is to investigate the process of the internalization of iron oxide nanoparticles, and to evaluate the effect of direct physical or mechanical damage on bacterial cell growth and death. The results demonstrate that iron oxide nanoparticles not only inhibited E. coli cell growth, but also caused bacterial cell death. Iron oxide nanoparticles produced significantly elevated ROS levels in bacteria. Transmission electronic microscopy demonstrated that iron oxide nanoparticles were internalized into and condensed the cytoplasm. Strikingly, we observed that the internalized nanoparticles caused intracellular vacuole formation, instead of simply adsorbing thereon; and formed clusters on the bacterial surface and tore up the outer cell membrane to release cytoplasm. This is the first time that the exact process of the internalization of iron oxide nanoparticles has been observed. We speculate that the intracellular vacuole formation and direct physical or mechanical damage caused by the iron oxide nanoparticles caused the bactericidal effect, along with the effects of ROS. Full article

(This article belongs to the Special Issue Selected Papers from the 6th International Conference on Biotechnology and Bioengineering (6-ICBB 2017))

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14 pages, 2889 KiB

Open AccessArticle

Preparative Purification of Polyphenols from Aronia melanocarpa (Chokeberry) with Cellular Antioxidant and Antiproliferative Activity

by Ningxuan Gao, Yuehua Wang, Xinyao Jiao, Shurui Chou, Enhui Li and Bin Li

Molecules 2018, 23(1), 139; https://doi.org/10.3390/molecules23010139 - 10 Jan 2018

Cited by 28 | Viewed by 5776

Abstract

The aim of this study was the purification process of polyphenols from Aronia melanocarpa (chokeberry), and the purification parameters were optimised by adsorption and desorption tests. By comparing adsorption and desorption ability of polyphenols from chokeberry on six kinds of macroporous resin, XAD-7 [...] Read more.

The aim of this study was the purification process of polyphenols from Aronia melanocarpa (chokeberry), and the purification parameters were optimised by adsorption and desorption tests. By comparing adsorption and desorption ability of polyphenols from chokeberry on six kinds of macroporous resin, XAD-7 resin was selected. Experiments prove that the best purification parameters of static adsorption and desorption were sample pH = 4.0 with 4 h of adsorption; and desorption solvent is 95% ethanol (pH = 7.0) with 2 h of desorption. The best dynamic parameters were 9.3 bed volume (BV) of sample loading amount at a feeding flow rate of 2 BV/h, and washing the column with 5.8 BV of water, followed by subsequent elution with an eluent volume of 5.0 mL at an elution flow rate of 2 BV/h. Next the antioxidant and antiproliferative activity of polyphenols from chokeberry, blueberries, haskap berries was studied on HepG2 human liver cancer cells. The results show that polyphenol from chokeberry has a strong antioxidant effect. Taking into account the content of polyphenols in fruit, polyphenols from chokeberry represent a very valuable natural antioxidant source with antiproliferative products. Full article

(This article belongs to the Special Issue Selected Papers from the 6th International Conference on Biotechnology and Bioengineering (6-ICBB 2017))

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1915 KiB

Open AccessArticle

Optimization of Goat Milk with ACE Inhibitory Peptides Fermented by Lactobacillus bulgaricus LB6 Using Response Surface Methodology

by Guowei Shu, Xiaoyu Shi, He Chen, Zhe Ji and Jiangpeng Meng

Molecules 2017, 22(11), 2001; https://doi.org/10.3390/molecules22112001 - 21 Nov 2017

Cited by 17 | Viewed by 4203

Abstract

In the present study, the incubation conditions of goat milk fermented by Lactobacillus bulgaricus LB6 were optimized to increase the angiotensin converting enzyme (ACE, EC 3.4.15.1) inhibitory activity by Box–Behnken design of response surface methodology. Incubation temperature, whey powder, and calcium lactate had [...] Read more.

In the present study, the incubation conditions of goat milk fermented by Lactobacillus bulgaricus LB6 were optimized to increase the angiotensin converting enzyme (ACE, EC 3.4.15.1) inhibitory activity by Box–Behnken design of response surface methodology. Incubation temperature, whey powder, and calcium lactate had significant effects on ACE inhibition rate and viable counts of LB6 during incubation. The results showed that optimal conditions of fermentation were found to be 37.05 °C, 0.8% (w/w) whey powder and 0.50% (w/w) calcium lactate. ACE inhibition rate increased significantly from 71.04 ± 0.37% to 83.31 ± 0.45% and the viable counts of Lactobacillus bulgaricus LB6 reached to 8.03 × 10⁷ cfu·mL⁻¹ under the optimal conditions, which approached the predicted values 83.25% and 8.04 × 10⁷ cfu·mL⁻¹. The optimal fermentation conditions can be a good reference for preparing ACE inhibitory peptides from goat milk. Full article

(This article belongs to the Special Issue Selected Papers from the 6th International Conference on Biotechnology and Bioengineering (6-ICBB 2017))

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2293 KiB

Open AccessArticle

Enantioselective Biosynthesis of l-Phenyllactic Acid by Whole Cells of Recombinant Escherichia coli

by Yibo Zhu, Ying Wang, Jiayuzi Xu, Jiahao Chen, Limei Wang and Bin Qi

Molecules 2017, 22(11), 1966; https://doi.org/10.3390/molecules22111966 - 15 Nov 2017

Cited by 20 | Viewed by 5327

Abstract

Background: l-Phenyllactic acid (l-PLA)—a valuable building block in the pharmaceutical and chemical industry—has recently emerged as an important monomer in the composition of the novel degradable biocompatible material of polyphenyllactic acid. However, both normally chemically synthesized and naturally occurring phenyllactic [...] Read more.

Background: l-Phenyllactic acid (l-PLA)—a valuable building block in the pharmaceutical and chemical industry—has recently emerged as an important monomer in the composition of the novel degradable biocompatible material of polyphenyllactic acid. However, both normally chemically synthesized and naturally occurring phenyllactic acid are racemic, and the product yields of reported l-PLA synthesis processes remain unsatisfactory. Methods: We developed a novel recombinant Escherichia coli strain, co-expressing l-lactate dehydrogenase (l-LDH) from Lactobacillus plantarum subsp. plantarum and glucose dehydrogenase (GDH) from Bacillus megaterium, to construct a recombinant oxidation/reduction cycle for whole-cell biotransformation of phenylpyruvic acid (PPA) into chiral l-PLA in an enantioselective and continuous manner. Results: During fed-batch bioconversion with intermittent PPA feeding, l-PLA yield reached 103.8 mM, with an excellent enantiomeric excess of 99.7%. The productivity of l-PLA was as high as 5.2 mM·h⁻¹ per OD₆₀₀ (optical density at 600 nm) of whole cells. These results demonstrate the efficient production of l-PLA by the one-pot biotransformation system. Therefore, this stereoselective biocatalytic process might be a promising alternative for l-PLA production. Full article

(This article belongs to the Special Issue Selected Papers from the 6th International Conference on Biotechnology and Bioengineering (6-ICBB 2017))

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2511 KiB

Open AccessArticle

Analysis of Floral Volatile Components and Antioxidant Activity of Different Varieties of Chrysanthemum morifolium

by Lu Yang, Aobulikasimu·Nuerbiye, Ping Cheng, Jin-Hui Wang and Hong Li

Molecules 2017, 22(10), 1790; https://doi.org/10.3390/molecules22101790 - 23 Oct 2017

Cited by 43 | Viewed by 7489

Abstract

This study investigated the volatile flavor compounds and antioxidant properties of the essential oil of chrysanthemums that was extracted from the fresh flowers of 10 taxa of Chrysanthemum morifolium from three species; namely Dendranthema morifolium (Ramat.) Yellow, Dendranthema morifolium (Ramat.) Red, Dendranthema morifolium [...] Read more.

This study investigated the volatile flavor compounds and antioxidant properties of the essential oil of chrysanthemums that was extracted from the fresh flowers of 10 taxa of Chrysanthemum morifolium from three species; namely Dendranthema morifolium (Ramat.) Yellow, Dendranthema morifolium (Ramat.) Red, Dendranthema morifolium (Ramat.) Pink, Dendranthema morifolium (Ramat.) White, Pericallis hybrid Blue, Pericallis hybrid Pink, Pericallis hybrid Purple, Bellis perennis Pink, Bellis perennis Yellow, and Bellis perennis White. The antioxidant capacity of the essential oil was assayed by spectrophotometric analysis. The volatile flavor compounds from the fresh flowers were collected using dynamic headspace collection, analyzed using auto thermal desorber–gas chromatography/mass spectrometry, and identified with quantification using the external standard method. The antioxidant activities of Chrysanthemum morifolium were evaluated by DPPH and FRAP assays, and the results showed that the antioxidant activity of each sample was not the same. The different varieties of fresh Chrysanthemum morifolium flowers were distinguished and classified by fingerprint similarity evaluation, principle component analysis (PCA), and cluster analysis. The results showed that the floral volatile component profiles were significantly different among the different Chrysanthemum morifolium varieties. A total of 36 volatile flavor compounds were identified with eight functional groups: hydrocarbons, terpenoids, aromatic compounds, alcohols, ketones, ethers, aldehydes, and esters. Moreover, the variability among Chrysanthemum morifolium in basis to the data, and the first three principal components (PC1, PC2, and PC3) accounted for 96.509% of the total variance (55.802%, 30.599%, and 10.108%, respectively). PCA indicated that there were marked differences among Chrysanthemum morifolium varieties. The cluster analysis confirmed the results of the PCA analysis. In conclusion, the results of this study provide a basis for breeding Chrysanthemum cultivars with desirable floral scents, and they further support the view that some plants are promising sources of natural antioxidants. Full article

(This article belongs to the Special Issue Selected Papers from the 6th International Conference on Biotechnology and Bioengineering (6-ICBB 2017))

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846 KiB

Open AccessArticle

Phytochemicals of Euphorbia lathyris L. and Their Antioxidant Activities

by Lizhen Zhang, Chu Wang, Qiuxia Meng, Qin Tian, Yu Niu and Wei Niu

Molecules 2017, 22(8), 1335; https://doi.org/10.3390/molecules22081335 - 18 Aug 2017

Cited by 19 | Viewed by 4784

Abstract

The objectives of this study were to characterize the antioxidant capacities and phytochemicals such as phenolics and flavonoids in four parts of Euphorbia lathyris L. HPLC was employed to detect the type and content of phenolic acids and flavonoids in the root, stem, [...] Read more.

The objectives of this study were to characterize the antioxidant capacities and phytochemicals such as phenolics and flavonoids in four parts of Euphorbia lathyris L. HPLC was employed to detect the type and content of phenolic acids and flavonoids in the root, stem, seed, and testa of the plant. The total phenolic content (TPC) and total flavonoid content (TFC) were different among various parts of E. lathyris. The highest TPC were found in the testa (290.46 ± 15.09 mg of gallic acid equiv/100 g dry weight (DW)). However, the root contained the highest TFC (215.68 ± 3.10 mg of rutin equiv/g DW). Of the different antioxidant activities detected, DPPH free radical scavenging activity was highest in the testa (61.29 ± 0.29 mmol Trolox/100 g DW), but the highest FRAP antioxidant activity was found in the seed (1131.25 ± 58.68 mg FeSO₄/100 g DW of free compounds and 1927.43 ± 52.13 mg FeSO₄/100 g DW of bound compounds). There was a positive correlation between the total phenolic contents and DPPH free radical scavenging activity in different parts of E. lathyris. Full article

(This article belongs to the Special Issue Selected Papers from the 6th International Conference on Biotechnology and Bioengineering (6-ICBB 2017))

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Review

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16 pages, 2137 KiB

Open AccessReview

Biocides Used as Additives to Biodiesels and Their Risks to the Environment and Public Health: A Review

by Glécia V. S. Luz, Breno A. S. M. Sousa, Adevilton V. Guedes, Cristine C. Barreto and Lourdes M. Brasil

Molecules 2018, 23(10), 2698; https://doi.org/10.3390/molecules23102698 - 19 Oct 2018

Cited by 18 | Viewed by 3801

Abstract

One of the advantages of using biodiesel and its blends with diesel oil is the lower levels of emissions of particulate matter, sulfur dioxide, carbon monoxide, among others, making it less harmful to the environment and to humans. However, this biofuel is susceptible [...] Read more.

One of the advantages of using biodiesel and its blends with diesel oil is the lower levels of emissions of particulate matter, sulfur dioxide, carbon monoxide, among others, making it less harmful to the environment and to humans. However, this biofuel is susceptible to microbial contamination and biodeterioration. In this sense, studies on the use of effective low toxicity biocides are being carried out, and this work aims to present the latest information (2008–2018) available in the scientific databases, on the use of biocides in biodiesel, mainly concerning their toxicity to the environment and public health. The results showed that in relation to the control of microbial contamination, the current scenario is limited, with seven publications, in which the most studied additives were isothiazolinones, oxazolidines, thiocyanates, morpholines, oxaborinanes, thiocarbamates and phenolic antioxidants. Studies regarding direct experiments with humans have not been found, showing the need for more studies in this area, since the potential growth of biodiesel production and consumption in the world is evident. Thus, there are need for more studies on antimicrobial products for use in biodiesel, with good broad-spectrum activity (bactericidal and fungicidal), and further toxicological tests to ensure no or little impact on the environment. Full article

(This article belongs to the Special Issue Selected Papers from the 6th International Conference on Biotechnology and Bioengineering (6-ICBB 2017))

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