Activity Of Fermentation Broth Research Articles

Effects of Konjac Glucomannan and Its Oligosaccharides on Improvement of Lactose Intolerance as Gut Prebiotics.

Lactose intolerance (LI) is a widespread health issue affecting almost 70% of the world population. This study evaluates the potential prebiotic benefits of konjac glucomannan (KGM) and konjac oligogalactomannan (KOGM) in improving LI. Colonic fermentation results indicate that lactase groups of healthy subjects showed lower pH, higher lactic acid content, and lactase activity in fermentation broth compared with LI subjects. Total short-chain fatty acid (SCFAs) content reached 1.71 mmol/L in healthy subjects, whereas it was 1.49 mmol/L in LI subjects. In vivo studies demonstrated that KGM and KOGM intake reduced total cholesterol (T-CHO) and triglyceride (TG) levels in the liver and significantly increased immunoglobulin G (lgG) and immunoglobulin A (lgA) values, while KOGM inclusion led to a significant 23.04% increase in serum free fatty acid (FFA) levels compared to the Blank group (p < 0.05). Furthermore, ileal tissue analysis revealed a marked increase in villus height and intestinal wall thickness (p < 0.05) as well as a decrease in crypt depth (p < 0.05). The composition and proportion of gut microbiota have improved with KGM and KOGM use, notably increasing the abundance of Lactobacillus and Lachnospiraceae_NK4A136_group, respectively (p < 0.05). Compared with the Blank group, Lactobacillus abundance increased by approximately 25.82% in the Drug group, 18.23% in the KGM group, and 8.67% in the KOGM group. These findings suggest that KGM and KOGM can be utilized as prebiotics to alleviate LI symptoms.

Advances in the homogeneous catalyzed alcohols homologation: The mild side of the Guerbet reaction. A mini-review

The Guerbet reaction would be an optimal solution for bio-ethanol refinery by homologation and it substantially requires the development of active and highly selective catalysts. Although heterogeneous catalysis remains more desirable, homogeneous Guerbet catalytic systems are nowadays acknowledged as challenging proposals for high selectivity and conversion under mild reaction conditions. Several molecular bi-functional catalysts, based on ruthenium, iridium and manganese complexes bearing different ligands such as phosphine, bidentate bisphosphine (P-P) and phosphamine (P-N), pincer (N-N-N), (P-N-P) and cyclopentadienone, are active in the co-presence of a base, which is essential in all the cases for the condensation reaction. This mini-review is aimed to describe the state of the art, with incremental steps forward to understand the role of the catalytic systems and the reaction conditions on conversion and selectivity. While showing different efficiency, mutable behavior by minimal change in the ligand scaffold, variation in water tolerance and only one example of recyclability, metal catalysts are found to be similar in terms of proposed mechanisms. The influence of additives and capability to maintain activity in fermentation broth and bio-ethanol from wine value chain to second generation bio-fuel are also discussed. Although not yet completely rationalized, experimental and theoretical mechanistic investigations pave the way for the design of more stable and efficient catalysts toward improved applicability.

Isolation, characterization, and genome sequencing of a novel chitin deacetylase producing Bacillus aryabhattai TCI-16.

Chitin deacetylase (CDA) is a chitin degradation enzyme that catalyzes the conversion of chitin to chitosan by the deacetylation of N-acetyl-D-glucosamine residues, playing an important role in the high-value utilization of waste chitin. The shells of shrimp and crab are rich in chitin, and mangroves are usually recognized as an active habitat to shrimp and crab. In the present study, a CDA-producing bacterium, strain TCI-16, was isolated and screened from the mangrove soil. Strain TCI-16 was identified and named as Bacillus aryabhattai TCI-16, and the maximum CDA activity in fermentation broth reached 120.35 ± 2.40 U/mL at 36 h of cultivation. Furthermore, the complete genome analysis of B. aryabhattai TCI-16 revealed the chitin-degrading enzyme system at genetic level, in which a total of 13 putative genes were associated with carbohydrate esterase 4 (CE4) family enzymes, including one gene coding CDA, seven genes encoding polysaccharide deacetylases, and five genes encoding peptidoglycan-N-acetyl glucosamine deacetylases. Amino acid sequence analysis showed that the predicted CDA of B. aryabhattai TCI-16 was composed of 236 amino acid residues with a molecular weight of 27.3 kDa, which possessed a conserved CDA active like the known CDAs. However, the CDA of B. aryabhattai TCI-16 showed low homology (approximately 30%) with other microbial CDAs, and its phylogenetic tree belonged to a separate clade in bacteria, suggesting a high probability in structural novelty. In conclusion, the present study indicated that the novel CDA produced by B. aryabhattai TCI-16 might be a promising option for bioconversion of chitin to the value-added chitosan.

Comparison of downstream processing methods in purification of highly active laccase

Laccases have received the attention of researchers in the last few decades due to their ability to degrade phenolic and lignin-related compounds. This study aimed at obtaining the highest possible laccase activity and evaluating the methods of its purification. The crude laccase from bioreactor cultivation of Cerrena unicolor fungus was purified using ultrafiltration, aqueous two-phase extraction (ATPE) and foam fractionation (FF), which allowed for the assessment of these three downstream processing (DSP) methods. The repeated fed-batch cultivation mode applied for the enzyme production resulted in a high laccase specific activity in fermentation broth of 204.1 U/mg. The use of a specially constructed spin filter inside the bioreactor enabled the integration of enzyme biosynthesis and biomass filtration in one apparatus. Other methods of laccase concentration and purification, namely ATPE and FF, proved to be useful for laccase separation; however, the efficiency of FF was rather low (recovery yield of 24.9% and purification fold of 1.4). Surprisingly, the recovery yield after ATPE in a PEG 6000-phosphate system in salt phase was higher (97.4%) than after two-step ultrafiltration (73.7%). Furthermore, it was demonstrated that a simple, two-step purification procedure resulted in separation of two laccase isoforms with specific activity of 2349 and 3374 U/mg. All in all, a compact integrated system for the production, concentration and separation of fungal laccases was proposed.

Construction of a food-grade arginase expression system and its application in L-ornithine production with whole cell biocatalyst

A food-grade recombinant Bacillus subtilis overexpressing arginase from Rummeliibacillus pycnus was successfully constructed based on replicative plasmids. D-Alanine racemase gene on the host chromosome was knocked out with Cre/lox system. Replacement of antibiotic resistance gene with dal in the plasmids would complement the deletion of the host strain and offer a selective pressure to keep plasmid segregational stability. Further deletion of argF was carried out to eliminate any effect of ornithine carbamoyltransferase. Then, constructed plasmid was transformed into engineered B. subtilis for arginase expression. The highest arginase activity in fermentation broth reached 42.1 U/mL at 16 h, and harvested cells could be used directly in L-ornithine bioconversion. Whole cell bioconversion was optimized and the reaction conditions were as follows: 200 g/L L-arginine, 1.5 mM Mn2+, pH 9.5 and 45 °C. In a scale up study, a final L-ornithine concentration of 342.2 g/L was obtained with a fed-batch strategy. The molar yield was calculated to be 90.2% with only 9.8 g/L L-arginine residue. Performance showed that this highly efficient whole cell biocatalyst has great potential for industrial L-ornithine production.

Species of Genus Ganoderma (Agaricomycetes) Fermentation Broth: A Novel Antioxidant and Antimicrobial Agent.

The bioactivity of Ganoderma lucidum basidiocarps has been well documented, but there are no data on the medicinal properties of its submerged cultivation broth nor on the other species of the genus Ganoderma. Thus the aim of this study was to test the potential antimicrobial and antioxidant activity of fermentation broth obtained after submerged cultivation of G. applanatum, G. carnosum, and G. lucidum. DPPH· scavenging ability, total phenols, and flavonoid contents were measured to determine the antioxidative potential of Ganoderma spp. fermentation filtrates, whereas their antimicrobial potential was studied using the microdilution method. DPPH· scavenging activity of G. lucidum fermentation filtrates was significantly higher than that of G. applanatum and G. carnosum, with the maximum (39.67%) obtained from strain BEOFB 432. This filtrate also contained the highest concentrations of phenols (134.89 μg gallic acid equivalents/mL) and flavonoids (42.20 μg quercetin equivalent/mL). High correlations between the activity and phenol content in the extracts showed that these compounds were active components of the antioxidative activity. G. lucidum strain BEOFB 432 was the most effective antibacterial agent, whereas strain BEOFB 434 has proven to be the most effective antifungal agent. The study showed that Ganoderma spp. fermentation filtrates are novel potent antioxidative and antimicrobial agents that could be obtained more quickly and cheaper than basidiocarps.

Recycling cellulases for cellulosic ethanol production at industrial relevant conditions: Potential and temperature dependency at high solid processes

Different versions of two commercial cellulases were tested for their recyclability of enzymatic activity at high dry matter processes (12% or 25% DM). Recyclability was assessed by measuring remaining enzyme activity in fermentation broth and the ability of enzymes to hydrolyse fresh, pretreated wheat straw. Industrial conditions were used to study the impact of hydrolysis temperature (40 or 50°C) and residence time on recyclability. Enzyme recycling at 12% DM indicated that hydrolysis at 50°C, though ideal for ethanol yield, should be kept short or carried out at lower temperature to preserve enzymatic activity. Best results for enzyme recycling at 25% DM was 59% and 41% of original enzyme load for a Celluclast:Novozyme188 mixture and a modern cellulase preparation, respectively. However, issues with stability of enzymes and their strong adsorption to residual solids still pose a challenge for applicable methods in enzyme recycling.

Overexpression of methyl parathion hydrolase and its application in detoxification of organophosphates

The coding region of mpd gene corresponding to mature methyl parathion hydrolase (MPH) was heterologously overexpressed in Escherichia coli BL21 (DE3) by using pET expression system. The lactose-induced expression yield of MPH is increased 2-fold compared with IPTG as inducer. Furthermore, it was found that specific activity of MPH increased 48% by reducing the induction temperature to 22 degrees C. The addition of 25 mM lactose at 22 degrees C, the MPH activity of fermentation broth had a specific activity of 1.4 x 10(4) U/mg protein. Plasmid was no significant decrease in the modified medium. The optimal pH and temperature of MPH were 8.0 and 30 degrees C, respectively. Over a period of 5 months, the dried cells showed no significant decrease in the activity of the detoxifying enzymes. The crude enzymes in 50 mM citrate-phosphate buffer (pH 8.0) were able to degrade about 98% of the organophosphate pesticides sprayed on cabbage. The detoxification efficiency was superior to that of the treatments of water, detergent, and a commercially available enzyme product. Additionally, the products of pesticide hydrolysis generated by treatment with the enzyme extract were determined to be virtually nontoxic.

Determination of mannuronan C-5-epimerase activity in fermentation broth of Azotobacter vinelandii

Azotobacter vinelandii produces extracellular mannuronan C-5-epimerase activity. This activity appears during the biosynthesis of alginate and converts d-mannuronic acid residues into l-guluronic acid in the polymer chain. In order to study the production of mannuronan C-5-epimerase by fermentation of A. vinelandii, a rapid and reproducible assay for the analysis of epimerase activity in the fermentation broth is required. We have examined a method in which [ 3H]-alginate is used as a substrate and the tritium released into water is measured. Fermentation broths contain compounds and ions which may interfere with the analysis or affect the activity of the enzyme. The effects of potential interfering compounds have been characterized and the uncertainty of the analysis system has been determined. Furthermore, a standard method suitable for use directly on the fermentation broth has been developed. The standard deviation of this method within a single analysis is ± 2.5% whereas the standard deviation for samples measured several times in separate analyses on the average is 10%.