Institut Charles Viollette

The recycling of industrial biomass waste, such as black liquor rich in lignin from the pulp and paper industry, represents a sustainable strategy to reduce environmental impact and promote resource valorization. Enzymatic depolymerization of lignin is considered a promising approach due to the high specificity of lignin-degrading enzymes. However, lignin’s poor solubility in aqueous and acidic conditions, combined with its structural complexity and recalcitrance, limits its enzymatic reactivity. In this study, Trametes versicolor laccase was used to depolymerize lignin following a sonication pretreatment designed to improve its solubility and reactivity. Response surface methodology (RSM) identified lignin concentration and sonication time as the most influential parameters for optimizing pretreatment efficiency. The enzymatic depolymerization process revealed a competition between condensation and depolymerization reactions. Characterization of the reaction products using GPC, FTIR, and NMR confirmed the formation of lignin-derived aromatic compounds. These findings highlight the effectiveness of sonication as a pretreatment method to enhance enzymatic lignin degradation. Future research will focus on integrating depolymerization and product separation processes to limit lignin repolymerization and increase the yield of depolymerized aromatic products.

The Collegiate of Sainte-Waudru in Mons, which was founded in the seventh century and evolved into a chapter of Secular Canonesses by the middle of the twelfth century, played a significant role in the book production in late medieval Hainaut. Two capitular acts, from 1265 and 1545, allocated portions of the Chapter’s prebendal income, derived from the Canonesses (all of noble origin and not bound by vows of poverty or required to relinquish their property), to cover liturgical expenses, including the purchase and repair of books and vestments. Between 1306 and 1623, records from seventy different years document payments for the production and the maintenance of liturgical books, revealing that approximately eighty craftsmen — secular and clerical — including scribes, illuminators, and bookbinders, were employed, with Tournai, Paris, and Antwerp as the main production centres. By examining the Latin 1269 lectionary (London, British Library, MS Egerton 2569), written by the English scribe John of Salisbury and commissioned by Dean Hermine de Héronfontaine (d. c. 1294), along with the unique French poem in it that names three Canonesses, this article highlights the Canonesses’ direct and multi-layered involvement in the manuscript’s creation process.

Streptococcus thermophilus is one of the most extensively applied members of the lactic acid bacteria, being extensively used as a bacterial starter culture in the production of fermented foods, including cheeses and yogurt. Bacteriophage infections present a significant threat to industrial dairy fermentations, which can lead to substandard production processes and product quality. Understanding phage-host interactions, which commence with the recognition and binding of a given bacteriophage to a particular host-encoded, cell surface-associated receptor, is essential for developing strategies to minimize phage-related risks in dairy fermentations. This study identifies the specific cell surface polysaccharide structure produced by Streptococcus thermophilus as the receptor required for infection by phage P738, bridging a key knowledge gap in phage-host interactions in this important industrial bacterial species. By elucidating how phage P738 recognizes and binds to its host, this work offers valuable information to aid strain selection and the development of phage-robust starter cultures.

This study aimed to identify and characterize bioactive peptides derived from protein hydrolysates of Arthrospira platensis (APPH) and Tetraselmis chuii (TCPH) using an integrated peptidomics and bioinformatics approach. Proteins extracted from the microalgae were hydrolyzed using pepsin (EC 3.4.23.1) at various enzyme/substrate (E/S) ratios. APPH and TCPH, prepared at an E/S ratio of 1/10 (w/w), were analyzed using peptidomics through reverse-phase high-performance liquid chromatography (RP-HPLC) coupled with tandem mass spectrometry (MS/MS). Using the UniProtKB database, a total of 265 unique peptides were identified, including 187 peptides from APPH and 78 peptides from TCPH. Subsequent in silico analysis of these peptides revealed favorable physicochemical properties, with a notable distribution of hydrophobic (APPH: 26; TCPH: 5), amphipathic (APPH: 70; TCPH: 16), and hydrophilic peptides (APPH: 59; TCPH: 17). Toxicity assessments confirmed that none of the peptides showed hemolytic or cytotoxic risks, except for one peptide identified in TCPH with potential cytotoxicity. Furthermore, bioactivity predictions demonstrated significant multifunctional properties (scores exceeding the 0.500 threshold), identifying peptides with antihypertensive (APPH: 2; TCPH: 1), anti-diabetic (APPH: 2), anti-inflammatory (APPH: 14; TCPH: 5) and antimicrobial (APPH: 7) activities. The current study thus establishes protein hydrolysates from A. platensis and T. chuii as promising sources of bioactive peptides suitable for nutraceutical applications. Our integrated analytical and computational strategy provides critical insights into peptide multifunctionality, supporting further research and development of microalgae-derived peptides.

The process to synthesize biodiesel is well-developed and optimized to overcome the disadvantages like the competition with agriculture using feedstock, and the problematics in the process. Oils from waste and enzymatic catalysis have proven to be good solutions to these problems. Lipases are currently the most commonly used enzymes in the transesterification of oils; nevertheless, enzymes have a high cost and must be immobilized to offer repetitive reuse. This work focuses on the synthesis and the optimization of the conditions of a xerogel where the lipase from Candida antarctica is immobilized by entrapment. The xerogel synthesized here, a glass-like material, proved to be very effective in maintaining the enzyme on its structure, with an immobilization yield of 96 % and an activity of 5.3 U/mg (free lipase=12.1 U/mg). By grinding this xerogel, the immobilization yield remained constant (94 %). Nevertheless, grinding the xerogel allowed better diffusion of reagents, and the activity reached 9.7 U/mg. Using this xerogel in biodiesel production had a positive effect on CALB efficiency by increasing the biodiesel yield, 46.1 % against 15.1 % with free CALB. Finally, the catalyst could be reused for five runs without loss of activity.

In the original published article, the wrong figure appeared as Fig. 4 ; the figure should have appeared as shown below. The original article has been corrected.

The COVID-19 pandemic caused by the SARS-CoV-2 virus has underscored the urgent necessity for the development of antiviral compounds that can effectively target coronaviruses. In this study, we present the first evidence of the antiviral efficacy of hyperforin, a major metabolite of St. John's wort, for which safety and bioavailability in humans have already been established. Antiviral assays were conducted in cell culture with four human coronaviruses: three of high virulence, SARS-CoV-2, SARS-CoV, and MERS-CoV, and one causing mild symptoms, HCoV-229E. The antiviral activity was also evaluated in human primary airway epithelial cells. To ascertain the viral step inhibited by hyperforin, time-of-addition assays were conducted. Subsequently, a combination assay of hyperforin with remdesivir was performed. The results demonstrated that hyperforin exhibited notable antiviral activity against the four tested human coronaviruses, with IC50 values spanning from 0.24 to 2.55 µM. Kinetic studies indicated that the observed activity occur at a post-entry step, potentially during replication. The antiviral efficacy of hyperforin was additionally corroborated in human primary airway epithelial cells. The results demonstrated a reduction in both intracellular and extracellular SARS-CoV-2 viral RNA, confirming that hyperforin targeted the replication step. Finally, an additive antiviral effect on SARS-CoV-2 was observed when hyperforin was combined with remdesivir. In conclusion, hyperforin has been identified as a novel pan-coronavirus inhibitor with activity in human primary airway epithelial cells, a preclinical model for coronaviruses. These findings collectively suggest that hyperforin has potential as a candidate antiviral agent against current and future human coronaviruses.