Production of Novel Polygalacturonase from Bacillus paralicheniformis CBS32 and Application to Depolymerization of Ramie Fiber

The Preparation and Potential Bioactivities of Modified Pectins: A Review

Pectins are complex polysaccharides that are widely found in plant cells and have a variety of bioactivities. However, the high molecular weights (M_w) and complex structures of natural pectins mean that they are difficult for organisms to absorb and utilize, limiting their beneficial effects. The modification of pectins is considered to be an effective method for improving the structural characteristics and promoting the bioactivities of pectins, and even adding new bioactivities to natural pectins. This article reviews the modification methods, including chemical, physical, and enzymatic methods, for natural pectins from the perspective of their basic information, influencing factors, and product identification. Furthermore, the changes caused by modifications to the bioactivities of pectins are elucidated, including their anti-coagulant, anti-oxidant, anti-tumor, immunomodulatory, anti-inflammatory, hypoglycemic, and anti-bacterial activities and the ability to regulate the intestinal environment. Finally, suggestions and perspectives regarding the development of pectin modification are provided.

A novel method of affinity purification and characterization of polygalacturonase of Aspergillus flavus by galacturonic acid engineered magnetic nanoparticle

Pectinases hydrolyze pectin and make up 25% of global food processing enzyme sales. In this study, we aimed to purify exo-polygalacturonase (Exo-PG) by using galacturonic acid conjugated magnetic nanoparticles (MNPs) and examined its application in juice purification. The submerged fermentation was carried out in the presence of apple pectin (1%) to promote production of exo-PG from Aspergillus flavus. Maximum exo-PG activity was observed after 4 days (30 °C and pH 5.0). A single protein band (66 kDa) of purified exo-PG was observed in SDS-PAGE. Purification of exo-PG enzyme was ∼ 10 fold with a yield of 29%. The enzyme retained 98% activity in the presence of 15 % glycerol at 4 °C. The purified exo-PG using MNPs yielded a 10-12% increase in juice production as compare to without treated fruit juice. To the best of our knowledge, this is the first report of affinity purification of exo-PG enzyme, using engineered magnetic nanoparticles.

Update of the list of QPS-recommended biological agents intentionally added to food or feed as notified to EFSA 14: suitability of taxonomic units notified to EFSA until March 2021

The qualified presumption of safety (QPS) approach was developed to provide a regularly updated generic pre-evaluation of the safety of biological agents, intended for addition to food or feed, to support the work of EFSA's Scientific Panels. The QPS approach is based on an assessment of published data for each agent, with respect to its taxonomic identity, the body of relevant knowledge, safety concerns and occurrence of antimicrobial resistance. Safety concerns identified for a taxonomic unit (TU) are, where possible, confirmed at the species/strain or product level and reflected by 'qualifications'. In the period covered by this statement, no new information was found that would change the status of previously recommended QPS TUs. Schizochytrium limacinum, which is a synonym for Aurantiochytrium limacinum, was added to the QPS list. Of the 78 microorganisms notified to EFSA between October 2020 and March 2021, 71 were excluded; 16 filamentous fungi, 1 Dyella spp., 1 Enterococcus faecium, 7 Escherichia coli, 1 Streptomyces spp., 1 Schizochytrium spp. and 44 TUs that had been previously evaluated. Seven TUs were evaluated: Corynebacterium stationis and Kodamaea ohmeri were re-assessed because an update was requested for the current mandate. Anoxybacillus caldiproteolyticus, Bacillus paralicheniformis, Enterobacter hormaechei, Eremothecium ashbyi and Lactococcus garvieae were assessed for the first time. The following TUs were not recommended for QPS status: A. caldiproteolyticus due to the lack of a body of knowledge in relation to its use in the food or feed chain, E. hormaechei, L. garvieae and K. ohmeri due to their pathogenic potential, E. ashbyi and C. stationis due to a lack of body of knowledge on their occurrence in the food and feed chain and to their pathogenic potential. B. paralicheniformis was recommended for the QPS status with the qualification 'absence of toxigenic activity' and 'absence of genetic information to synthesize bacitracin'.

Partial Purification and Characterisation of Pectinase Produced by Aspergillus niger LFP-1 Grown on Pomelo Peels as a Substrate

In the present study, pectinase was produced by local fungal isolate, Aspergillus niger LFP-1 grown on pomelo peels as a sole carbon source under solid-state fermentation (SSF). The purification process begins with the concentration of crude enzyme using ammonium sulfate precipitation and followed by purification using anion-exchange column chromatography (DEAE-Sephadex) and subsequently using gel filtration column chromatography (Sephadex G-100). On the other hand, the molecular weight of the purified enzyme was determined through SDS-PAGE. The findings revealed the crude enzyme was purified up to 75.89 folds with a specific activity of 61.54 U/mg and the final yield obtained was 0.01%. The molecular mass of the purified pectinase was 48 kDa. The optimum pH and temperature were 3.5 and 50°C, respectively. This enzyme was stable at a range of pH 3.5 to 4.5 and a relatively high temperature (40°C–50°C) for 100 min. The K_m and V_max were found to be 3.89 mg/mL and 1701 U/mg, respectively. Meanwhile, pectin from citrus fruit and the metal ion (Co²⁺) were the best substrate and inducer to enhance pectinase yield, respectively.