Process Biochemistry最新文献

In colder regions, relatively low temperatures results in low microbial activity and low biogas production in anaerobic digestion. This study investigated if microbial electrosynthesis system (MES) can enhance biogas production from pig manure wastewater under sub-psychrophilic conditions (20 °C). Results showed that the applied voltage of MES (0.4 V and 0.8 V) significantly increased the biogas production and COD removal rate. Biogas production and COD removal rate increased most when the voltage reached 0.8 V (34.77 %, 26.67 %), and decreased when the voltage was 1.2 V. Low voltage (≤ 0.8 V) did not significantly alter the microbial structure, but higher voltage (1.2 V) resulted in a significant decrease in Clostridium and Methanosarcina. Coenzyme F420, NADH, as indicators for methanogenic efficiency, showed the highest fluorescence intensity at 0.8 V and decreased at 1.2 V. Results indicated that the improvement of gas production was mainly due to the improvement of key enzymes rather than the shift of microbial structure. The information provided will be useful to improve the efficiency of biogas production.

This study investigated the conditions for polygonati rhizoma (PR) fermentation by Monascus ruber and the lipid-lowering activity of the resulting product. Monascus ruber was used for the solid-state fermentation of PR, and the response surface method was used to optimize the fermentation culture medium parameters. The optimal fermentation system yielded a maximum monacolin K concentration of 21.82 ± 0.34 mg/g. The fermentation conditions were as follows: 12.5 mmol/kg of L-glutamic acid, 0.64 mmol/kg of cyclic adenosine monophosphate, 3.0 wt% of yeast extract powder, a fermentation period of 15 days, and a fermentation temperature of 30 ℃. The binding capacities of unfermented PR, “Nine-Steam-Nine-Bask” processed Polygonati rhizoma (NPR), and Monascus ruber solid-state fermented polygonati rhizoma (MPR) to sodium cholate, sodium taurocholate, and sodium glycolate were determined. MPR showed a stronger bile acid-binding capacity than unfermented PR. In addition, MPR exhibited the highest cholesterol inhibitory capacity of 51.43±1.41 %. Thus, MPR can be used as a potential antilipemic agent with potent hypolipidemic effects.

Chitosan, a derivative of chitin derived from the gladius of the marine cephalopod Doryteuthis sibogae, has drawn interest in biomedical research because of its possible antibacterial effects on human infections and inhibition of blood clotting. Chitosan was extracted from chitin isolated from the gladius of D. sibogae via demineralization and deproteination. Chitosan was structurally characterized using FT-IR, XRD, and FESEM. Additionally, the disc diffusion method was used to investigate the antibacterial efficacy of chitosan against three human pathogens. Effective antibacterial activity was demonstrated against both Gram-positive and Gram-negative microorganisms. Chitosan is a potent anticoagulant in anticoagulant assays employing activated partial thromboplastin time (APTT) and prothrombin time (PT).

Laccases are enzymes with low substrate specificity that in certain cases require the presence of a mediator in order to work properly. Therefore, this paper investigated the degradation of Orange G, Ponceau 4 R and Methyl Red in the presence of laccase isolated from Trametes versicolor and laccase-ABTS system. Laccase, in high concentration, was able to oxidize only Orange G and Ponceau 4 R, with a degree of decolorization less than 10 % in 20 min. In the presence of laccase-ABTS system, the reaction is much faster, and at least 40 % of dyes were degraded in 15 min. A kinetic model accounting for enzymatic oxidation of all dyes, including a step for enzyme operational inactivation, was proposed. This study proves that we can use a single kinetic model for the oxidation of all dyes in the laccase-ABTS system.

Over the past decades, the heat-inducible (HI) promoter, derived from cI857 phage system has been widely utilized. However, the developments of alternative temperature-controlled promoters are limited. In this study, we explored a novel HI promoter through PCR amplification using the degenerate primer design. BLAST analysis identified this sequence as a partial plsB on Escherichia coli chromosome. Antisense RNAs targeting distinct regions of HI promoter were applied to examine the mechanism. The fluorescence of super-folder green fluorescent protein (sfGFP) driven by the HI promoter showed 5.5-fold increase from 30 to 42 ^oC, whereas the truncated HI yielded a trace amount of sfGFP. Among various E. coli strains, BL21 exhibited the highest fluorescence, reaching 3976 a.u. at 42°C. Subsequently, the novel HI promoter was employed to drive T7RNA polymerase within a plasmid-driven T7 (PDT7) plasmid, serving its capability to express sfGFP and carbonic anhydrases (CA), respectively. The maximum intensity of sfGFP reached 38702 a.u., and CA activity surged to 14286 WAU/mL in W3110 among other strains. Finally, the highest CA activity was 27521 WAU/mL at alkali pH 9. The promising results from the novel heat-inducible promoter-driven T7RNAP, incorporating the T7 terminator as HI-PDT7-TT, demonstrate potential for expressing more heterogeneous proteins across various chassis in the future.

The fungus Ophiocordyceps sinensis OS8 has been sourced from the wild variant of O. sinensis. In this study, the enriched β-D-glucan polysaccharide obtained from cultured mycelium of O. sinensis OS8 (OS8P) was examined for its potential to inhibit the growth of HepG2 liver cancer cells, and the IC₅₀ was 511.79 µg/mL. The study of cellular migration was analyzed by scratch assay. It was found that the HepG2 cell migration was significantly inhibited (P < 0.05) in the OS8P-treated group. The cell apoptotic feature’s reliability was determined via DAPI staining to confirm the experimental results' reliability. The AO/PI double staining assay showed that HepG2 cells treated with OS8P (IC₅₀) had dead cells with condensed and shrieking nuclei that are late apoptotic. Morphological alterations were meticulously examined using scanning electron microscopy. The specific morphological characteristics of apoptotic cells, notably cell lysis, were distinctly observable. The damaged cells demonstrated severe structural disruption, loss of original shape, blebs formation, and apoptotic bodies' appearance. These findings provide pharmacological proof that the OS8P extract could be potentially employed in the food and medical industries for anticancer applications.

Clerodendrum viscosum Vent. is a well-known plant in Indian and Chinese traditional medicine systems. While studies showed its crude leaf extract's cytotoxicity against HT-29 and HeLa cells, various non-bioactive compounds present in crude extracts may influence overall bioactivity. This study aimed to separate the most bioactive fractions from Clerodendrum viscosum’s crude extracts that exhibit anticancer potential against HepG2 cells. Crude extracts were fractionated using a solvent-polarity-based process and their anticancer activity was investigated through in vitro, in silico, and network pharmacology approaches. Nonpolar leaf (CVL_H) and root (CVR_H) fractions showed maximum cytotoxicity in HepG2 cells without affecting noncancer-origin WRL68 cells. Both extracts induced oxidative stress, DNA damage, cell cycle arrest, and apoptosis in HepG2 cells, with CVR_H exhibiting a superior effect. GC-MS analysis identified various anticancer phytochemicals differentially present in CVL_H and CVR_H. Network pharmacology with these phytochemicals predicted Bcl-2 as the primary target, while molecular docking confirmed lupeol, stigmasterol, alpha-amyrin, cycloartenol, and calysterol being the top five phytochemicals exhibiting strong binding against Bcl-2, androgen receptor (AR), and epidermal growth factor receptor (EGFR). Western blot confirmed an elevated Bax/Bcl-2 ratio in HepG2 cells by CVL_H and CVR_H. In summary, the nonpolar fractions of Clerodendrum viscosum leaf and root crude extracts showed enhanced anticancer activity, suggesting their potential pharmaceutical applications.

This study aimed to elucidate the impact of mildew on the quality of fermented cigar tobacco leaves (CTLs) and identify potential biomarkers. Chemical constituents, microbial communities and metabolites in healthy CTLs (HCTLs) and mildewed CTLs (MCTLs) were systematically analyzed. Compared with HCTLs, the moisture, reducing sugar and total nitrogen contents of MCTLs increased, but the levels of starch, protein, total sugar and carbon-nitrogen ratio decreased. Mildew significantly altered flavor profiles, with 31 volatile flavor compounds (VFCs) and 9 free amino acids (FAAs) showing significant differences. Furthermore, the richness and diversity of bacterial and fungal communities decreased with mildew. The core functional microorganisms, including Pseudomonas, Pectobacterium, Aerococcus, Aspergillus, Alternaria, and Colletotrichum were screened. Notably, 2 chemical components (total acid, reducing sugar), 3 VFCs (2-undecanone,6,10-dimethyl, myosmine, 1-(5-methylfuran-2-yl)ethenone), and 4 FAAs (Asp, Ile, Val, Gly) were proposed as biomarkers indicating mildew tendency in fermented CTLs. These findings provide theoretical foundation for optimizing cigar production.

The cyclodextrins (CDs) market has increased due to their numerous applications, especially in the food and pharmaceutical industries. The high cost of synthetizing one unique form of CDs, mainly the α- and γ- forms, hinders their use in certain processes. Since CDs are exclusively produced by the enzymatic conversion of starch or starch derivates using cyclodextrin glycosyltransferase (CGTase), enhancing this enzyme production means feasible CD synthesis. Recent discoveries of novel CGTase producers and strategies for optimizing fermentation processes and immobilization techniques have expanded its applications. However, the low yield arising from wild strains remains an obstacle. Studies focused on overexpressing CGTase through heterologous expression and improving their catalytic properties by altering protein structure using protein engineering approaches have been explored to enable upscaling the applications of CGTase. This review surveys recent approaches employed in CGTases production aiming at industrial scale. Overall, the importance of advances in biotechnology for cost reduction in upscale processes and perspectives for future research were highlighted.

In this study, we aimed to (i) better understand the phytochemical composition of extracts prepared from the leaves and roots with rhizomes of the scarcely studied Iris versicolor, and (ii) propose optimal extraction conditions (solvent composition, temperature, time) for the isolation of bioactive compounds. A UHPLC-QTOF-MS/MS targeted screening method was applied in combination with in silico fragmentation. The analysis revealed a total of 106 target metabolites, many of which are reported to occur in I. versicolor for the first time. (Iso)flavonoids were the most abundant compounds, followed by terpenoids, phenols, xanthones, phenolic acids, quinones, and steroids, with quinones being reported for the first time in this species. Terpenoids were characteristic of roots with rhizomes, while xanthones dominated in the leaves. Based on the varied experimental conditions, surface response analysis generated significant models for the extraction of terpenoids, quinones, and steroids. Our research provides valuable insight for the effective medicinal and commercial use of I. versicolor.