Search Results (112)

Biobutanol is becoming more relevant as a promising alternative biofuel, primarily due to its advantageous characteristics. These include a higher energy content and density compared to traditional biofuels, as well as its ability to mix effectively with gasoline, further enhancing its viability as a potential replacement. A viable strategy for attaining carbon neutrality, reducing reliance on fossil fuels, and utilizing sustainable and renewable resources is the use of biomass to produce biobutanol. Lignocellulosic materials have gained widespread recognition as highly suitable feedstocks for the synthesis of butanol, together with various value-added byproducts. The successful generation of biobutanol hinges on three crucial factors: effective feedstock pretreatment, the choice of fermentation techniques, and the subsequent enhancement of the produced butanol. While biobutanol holds promise as an alternative biofuel, it is important to acknowledge certain drawbacks associated with its production and utilization. One significant limitation is the relatively high cost of production compared to other biofuels; additionally, the current reliance on lignocellulosic feedstocks necessitates significant advancements in pretreatment and bioconversion technologies to enhance overall process efficiency. Furthermore, the limited availability of biobutanol-compatible infrastructure, such as distribution and storage systems, poses a barrier to its widespread adoption. Addressing these drawbacks is crucial for maximizing the potential benefits of biobutanol as a sustainable fuel source. This document presents an extensive review encompassing the historical development of biobutanol production and explores emerging trends in the field. Full article

Thermostable cellulases and xylanases have broad acceptance in food, feed, paper and pulp, and bioconversion of lignocellulosics. Thermophilic fungi serve as an excellent source of thermostable enzymes. This study characterized four endo-β-1,4-glucanases (two glycoside hydrolase (GH) family 5 and two GH7 members) and four endo-β-1,4-xylanases (two GH10 and two GH11 members) from thermophilic fungus Thielavia terrestris, along with one GH10 endo-β-1,4-xylanase each from thermophilic fungus Chaetomium thermophilum and mesophilic fungus Chaetomium globosum. Comparative analysis was conducted against three previously reported GH10 endoxylanases: two thermostable enzymes from the thermophilic fungus Humicola insolens and thermophilic bacterium Halalkalibacterium halodurans, and one mesophilic enzyme from model fungus Neurospora crassa. The GH10 xylanase TtXyn10C (Thite_2118148; UniProt G2R8T7) from T. terrestris demonstrated high thermostability and activity, with an optimal temperature of 80–85 °C. It retained over 60% of its activity after 2 h at 70 °C, maintained approximately 30% activity after 15 min at 80 °C, and showed nearly complete stability following 1 min of exposure to 95 °C. TtXyn10C exhibited specific activity toward beechwood xylan (1130 ± 15 U/mg) that exceeded xylanases from H. insolens and H. halodurans while being comparable to N. crassa xylanase activity. Furthermore, TtXyn10C maintained stability across a pH range of 3–9 and resisted trypsin digestion, indicating its broad applicability. The study expands understanding of enzymes from thermophilic fungi. The discovery of the TtXyn10C offers a new model for investigating the high activity-stability trade-off and structure-activity relationships critical for industrial enzymes. Full article

Bioconversion of cortisone leads to the synthesis of the steroid derivatives 1,9β,17,21-tetrahydroxy-4-methyl-19-nor-9β-pregna-1,3,5(10)-trien-11,20-dione (SCA) and 1,9β,17,20β,21-pentahydroxy-4-methyl-19-nor-9β-pregna-1,3,5(10)-trien-11-one (SCB), which have been identified as biologically active molecules in affections associated with oxidative stress and inflammation, particularly in the skin and eye. To date, the synthesis of SCA and SCB can only be achieved through a biocatalytic approach, following a biotransformation process catalyzed by Rhodococcus rhodnii DSM 43960, a synthetic pathway that adheres to the principles of green chemistry. To further enhance the sustainability of this process, this study demonstrated that SCA and SCB can be synthesized by bioconversion in a complex medium derived from a dual upcycling process involving olive leaves (UOLM). By formulating a medium based on olive leaves, a by-product derived from the previously reported biotechnological production of lactic acid, and using a concentration of 10% v/v UOLM and 1 g/L cortisone at pH 7.5, bioconversion yields of 90 ± 4.5% were achieved, with a predominance of SCB. Investigations into the addition of supplements, such as tryptone, peptone, and corn steep liquor (CSL), to assess potential improvements in yield were conducted, but no significant positive variations were observed. For the first time, bioactive steroids were synthesized from a medium obtained through a dual upcycling process of olive leaves, introducing an innovative method that opens new possibilities for the investigation of a second generation of biosteroids synthesized from lignocellulosic feedstocks. Full article

Microbial decomposition of persistent natural compounds such as phenolic lignin and polysaccharides in plant cell walls plays a crucial role in the global carbon cycle and underpins diverse biotechnological applications. Among microbial decomposers, fungi from the Ascomycota and Basidiomycota phyla have evolved specialized mechanisms for efficient lignocellulosic biomass degradation, employing extracellular enzymes and synergistic fungal consortia. Fungal coculture, defined as the controlled, axenic cultivation of multiple fungal species or strains in a single culture medium, is a promising strategy for industrial processes. This approach to biomass conversion offers potential for enhancing production of enzymes, biofuels, and other high-value bioproducts, while enabling investigation of ecological dynamics and metabolic pathways relevant to biorefinery operations. Lignocellulosic biomass conversion into fuels, energy, and biochemicals is central to the bioeconomy, integrating advanced biotechnology with sustainable resource use. Recent advancements in -omics technologies, including genomics, transcriptomics, and proteomics, have facilitated detailed analysis of fungal metabolism, uncovering novel secondary metabolites and enzymatic pathways activated under specific growth conditions. This review highlights the potential of fungal coculture systems to advance sustainable biomass conversion in alignment with circular bioeconomy goals. Full article

Lignocellulosic biomass, derived from plant materials, represents a renewable alternative to fossil fuels and plays a crucial role in advancing environmental sustainability. This systematic review investigates recent developments in the conversion of lignocellulosic biomass into biofuels, with a focus on pre-treatment technologies that enhance enzymatic hydrolysis, a critical step in efficient biofuel production. This review addresses two primary questions: (1) What are the most effective pre-treatment methods for enhancing enzymatic hydrolysis in lignocellulosic biomass conversion? (2) How do these pre-treatment methods compare in terms of efficiency, environmental impact, and economic feasibility? Consequently, studies were selected based on inclusion criteria that focus on research investigating these pre-treatment methods and their comparative performance. A structured search of original studies was applied across databases such as Crossref, Google Scholar, Scopus, PubMed, and Semantic Scholar, resulting in the inclusion of 17 peer-reviewed articles published between 2019 and 2024. The findings highlight effective pre-treatment methods that significantly improve enzymatic accessibility and bioethanol yields. However, ongoing challenges such as feedstock variability, process efficiency, and cost-effectiveness remain. These results highlight the need for further research and development to optimize conversion technologies and identify new areas for exploration. Full article

Efficient bioconversion of lignocellulosic biomass into ruminant feed requires advanced strategies to enhance fiber degradation and ruminal fermentation efficiency. This study evaluates the synergistic effects of gamma irradiation (150 kGy) and exogenous fibrolytic enzyme (EFE) supplementation (4 µL/g dry matter) from Trichoderma longibrachiatum on the structural composition and ruminal fermentation of Typha latifolia. Gamma irradiation significantly reduced neutral detergent fiber (NDF) while increasing non-fiber carbohydrates (NFCs), reducing sugars (RS) and antioxidant activity. These modifications enhanced ruminal bacterial proliferation, suppressed ruminal protozoal populations, and improved ruminal fermentation efficiency by increasing gas production, dry matter degradability, and NDF degradability. Additionally, irradiation decreased ruminal NH₃-N concentrations and branched-chain volatile fatty acids (VFAs) without affecting total VFA production and ruminal pH. While EFE alone accelerated only ruminal fermentation, its combination with irradiation further reduced NDF content, enriched NFC and RS, and enhanced fermentation efficiency. This dual treatment increased total VFA production, shifted fermentation pathways toward propionate synthesis, and reduced acetate and branched-chain VFA levels. It also stimulated ruminal bacterial populations without altering ruminal pH. These findings highlight gamma irradiation as an effective pretreatment to enhance EFE hydrolysis, offering a promising strategy to improve the nutritional value of low-quality forages to integrate into ruminant diets. Full article

The efficient degradation of lignocellulose is essential for valorizing agricultural waste and reducing environmental pollution. An efficient degradation process requires an enzyme cocktail capable of comprehensively deconstructing lignocellulosic components. In this study, the secretome of Coriolopsis trogii Mafic-2001 induced by rice straw was examined, and the enzymatic composition and reaction conditions of Coriolopsis trogii were optimized. Mafic-2001 secreted an enzyme cocktail that included ligninolytic enzymes, cellulases, and hemicellulases. However, the relative abundances of endoglucanase (EG) and β-glucosidase (βG) were only 64.37% and 10.69%, respectively, compared with the relative abundance of cellobiohydrolase, which indicated a critical bottleneck in degradation efficiency. To overcome this limitation, the recombinant enzymes rEG1 and rβG1 were expressed in Pichia pastoris X-33. A functionally enhanced enzyme cocktail (rEG1–rβG1–Mafic-2001 = 0.05:0.09:0.86) was developed via a mixture design to achieve a reducing sugar yield of 2.77 mg/mL from Chinese distillers’ grains (CDGs). Structural analyses revealed that the optimized enzyme cocktail disrupted the reticulated fiber architecture of CDGs and attenuated the characteristic Fourier-transform infrared spectroscopy peaks of lignin, cellulose, and hemicellulose. This study elucidates the synergistic lignocellulose deconstruction mechanism of Mafic-2001 and establishes a precision enzyme-supplementation strategy for efficient CDG bioconversion, providing a scalable platform for the valorization of lignocellulosic biomass. Full article

This study aims to optimize the bioconversion of palm kernel cake (PKC) by Pleurotus ostreatus to improve fungal biomass production, lignocellulolytic enzyme expression, and the nutritional value of the substrate as ruminant feed. Three inorganic nitrogen sources (ammonium sulfate, ammonium nitrate, and urea) were evaluated for fungal biomass production using a central composite design (CCD) in liquid fermentations. The formulated culture medium (18.72 g/L glucose and 0.39 g/L urea) effectively yielded better fungal biomass production (8 g/L). Based on these results, an extreme vertex design, mixtures with oil palm by-products (PK, hull, and fiber) supplemented with urea, were formulated, finding that PKC stimulated the highest biomass production and laccase enzyme activity in P. ostreatus. The transcriptome of P. ostreatus was obtained, and the chemical composition of the fermented PKC was determined. Transcriptomic analysis revealed the frequency of five key domains with carbohydrate-activated enzyme (CAZy) function: GH3, GH18, CBM1, AA1, and AA5, with activities on lignocellulose. In the fermented PKC, lignin was reduced by 46.9%, and protein was increased by 69.8%. In conclusion, these results show that urea is efficient in the bioconversion of PKC with P. ostreatus as a supplement for ruminants. Full article

Lignocellulosic biomass is widely recognized as a renewable resource for bioconversion. However, the presence of inhibitors such as furfural, 5-HMF, and acetic acid can inhibit cell growth, thereby affecting the overall efficiency of the bioconversion process. The studies on the degradation of lignocellulosic hydrolysate inhibitors by Saccharomyces cerevisiae have been limited. In this research, a yeast strain Kodamaea ohmeri can degrade inhibitors furfural, 5-HMF, and acetic acid, and the genome sequence of the strain was analyzed. Furthermore, the molecular detoxification mechanism of K. ohmeri SSK against lignocellulosic hydrolysate inhibitors was predicted using whole genome sequencing. Annotation based on the COG/KEGG databases identified 57 key detoxification genes, including the alcohol dehydrogenase (ADH) gene, aldo-keto/aldehyde reductase (AKR/ARI) gene, and aldehyde dehydrogenase (ALDH) gene. Stress tolerance experiments revealed that the maximum tolerance concentration for the strain was 5.2 g/L of furfural, 2.5 g/L of 5-HMF, and 5.9 g/L of acetic acid, respectively. A NAD(P)⁺-dependent bifunctional enzyme with possible ADH and ARI activities was found by conserved domain analysis. Phylogenetic analysis indicated that this enzyme shared 99% homology with the detoxification enzyme from S. cerevisiae S288C (GenBank: Q04894.1). This study represents the first comprehensive analysis of the inhibitor detoxification network in K. ohmeri SSK from a genome perspective, providing theoretical targets and design strategies for developing highly efficient biorefinery strains. Full article

Cellulosomes are sophisticated multi-enzyme complexes synthesized and secreted by anaerobic microorganisms, characterized by intricate structural components and highly organized modular assembly mechanisms. These complexes play a pivotal role in the efficient degradation of lignocellulosic biomass, significantly enhancing its bioconversion efficiency, and are thus regarded as invaluable enzymatic molecular machines. Cellulosomes are not only prevalent in anaerobic bacteria from soil and compost environments but are also integral to the digestive systems of herbivorous animals, primates and termites. The cellulosomes produced by digestive tract microbiota exhibit unique properties, providing novel enzymes and protein modules that are instrumental in biomass conversion and synthetic biology, thereby showcasing substantial application potential. Despite their promise, the isolation and cultivation of digestive tract microorganisms that produce cellulosomes present significant challenges. Additionally, the lack of comprehensive genetic and biochemical studies has impeded a thorough understanding of these cellulosomes, leaving them largely underexplored. This paper provides a comprehensive overview of the digestive tract cellulosome system, with a particular focus on the structural and functional attributes of cellulosomes in various animal digestive tracts. It also discusses the application prospects of digestive tract cellulosomes, highlighting their potential as a treasure in diverse fields. Full article

The valorization of agricultural residues, particularly corn stover, represents a sustainable approach for resource utilization and protein production in which high-performing microbial strains are essential. This study systematically evaluated fungal lignocellulolytic capabilities during corn stover solid-state fermentation and employed atmospheric and room-temperature plasma (ARTP) mutagenesis to enhance the degradative capacity of Trichoderma longibrachiatum. Comparative screening revealed that T. longibrachiatum exhibited superior comprehensive degradation of the major lignocellulosic components compared to other tested strains. ARTP mutagenesis yielded mutant strain TL-MU07, which displayed significantly enhanced enzymatic capabilities with improvements in FPase (22.1%), CMCase (10.1%), and xylanase (16.1%) activities, resulting in increased cellulose degradation (14.6%) and protein accumulation (14.7%). Proteomic analysis revealed 289 significantly differentially expressed proteins, with pathway enrichment demonstrating enhancement of glycosaminoglycan degradation, amino sugar metabolism, and membrane remodeling. Key mechanistic adaptations included downregulation of Zn(2)-C6 transcriptional repressors, upregulation of detoxification enzymes (ALDH-like proteins), and enhanced secretory pathway components. The ARTP-derived mutant strain TL-MU07 represents a valuable microbial resource for agricultural waste bioconversion, offering enhanced lignocellulolytic capabilities for industrial applications while elucidating specific proteomic changes associated with improved biomass degradation efficiency for sustainable protein production in the circular bioeconomy. Full article

The valorization of agri-food wastes can provide value-added products, enzymes and biofuels. For the second-generation ethanol (2G) production, pulps rich in cellulose are desirable in order to release fermentable sugars. This study investigated the homemade biosynthesis of cellulases and hemicellulases via solid-state fermentation (SSF) using sugarcane bagasse (SB) and wheat bran (WB) for the growth of endophytic fungi (Beauveria bassiana, Trichoderma asperellum, Metarhizium anisopliae and Pochonia chlamydosporia). Cocktails with high enzymatic levels were obtained, with an emphasis for M. anisopliae in the production of β-glucosidase (83.61 U/g after 288 h) and T. asperellum for xylanase (785.50 U/g after 144 h). This novel M. anisopliae β-glucosidase demonstrated acidophile and thermotolerant properties (optimum activity at pH 5.5 and 60 °C and stability in a wide pH range and up to 60 °C), which are suitable for lignocellulose saccharifications. Hence, the M. anisopliae multi-enzyme blend was selected for the hydrolysis of raw and organosolv-pretreated corn straw (CS) and corncob (CC) using 100 CBU/g cellulose. After the ethanol/water (1:1) pretreatment, solid fractions rich in cellulose (55.27 in CC and 50.70% in CS) and with low concentrations of hemicellulose and lignin were found. Pretreated CC and CS hydrolysates reached a maximum TRS release of 12.48 and 13.68 g/L, with increments of 100.80 and 73.82% in comparison to untreated biomass, respectively, emphasizing the fundamental role of a pretreatment in bioconversions. This is the first report on β-glucosidase biosynthesis using M. anisopliae and its use in biomass hydrolysis. These findings demonstrated a closed-loop strategy for internal enzyme biosynthesis integrated to reducing sugar release which would be applied for further usage in biorefineries. Full article

The enzymatic hydrolysis of lignocellulosic biomass is often hindered by lignin, which acts as a physical barrier and promotes non-productive enzyme adsorption. This study evaluated the potential of soybean protein in powdered and cavitated forms, along with lactonic sophorolipid biosurfactant (LSLB), to enhance sugar yields from cellulignin derived from sugarcane bagasse, a residue with a high lignin content. A Box–Behnken design was used to investigate the effects of enzyme loading (10–20 FPU/g cellulignin), soybean protein powder (10–30% w/w of dried cellulignin), and LSLB concentration (25–250 mg/L) on glucose and xylose yields. Hydrodynamic cavitation was employed to produce soluble soybean protein, achieving a solubility yield of 44.4% w/w in 10 min. The cavitated protein was compared with powdered protein to assess its impact on enzymatic hydrolysis efficiency. The results showed that hydrodynamic cavitation reduced the required SBP dosage while maintaining sugar yields, allowing 10% w/w of dried cellulignin cavitated SBP to achieve glucose and xylose yields comparable to 25% w/w of dried cellulignin non-cavitated SBP. Specifically, glucose yield increased by 24.92% (from 34.1% ± 1.01 to 42.6% ± 1.4), and xylose yield by 30.86% (from 32.4% ± 0.53 to 42.4% ± 2.21) compared to the no-additive condition. These improvements were linked to enhanced solubility, increased surface area, and reduced particle size in the cavitated protein. This study highlights hydrodynamic cavitation as a novel approach for modifying soybean protein structure to optimize enzymatic hydrolysis in lignocellulosic bioconversion. Full article

Biomass residues represent a major issue for industries. On the other hand, residues enclosed major classes of bioactive compounds that could be extracted and used across various fields. This study aimed to elucidate the role of the endogenous microbial community in the lignocellulosic degradation of hemp residues for biorefineries or other industrial processes, simultaneously characterizing the composition of three extracts recovered at different stages of maceration. The process was examined from different perspectives: plant tissue degradation and microbial dynamics were monitored using histological, cultural-dependent, and independent analysis. Extracts were characterized through FTIR, NMR, and SDS-PAGE analyses, also evaluating their potential as biostimulants for microbial growth. Results revealed that the composition of the endogenous prokaryotic community remained stable during the maceration period, while fluctuations in various fungal genera were observed. The taxonomical composition of hemp residues at different stages may account for the increased accumulation of amide-containing compounds, sugars, and other metabolites detected in long-term bioconversion. Finally, the extracts recovered from the microbial degradation of hemp residues were able to support the growth of the yeast Cryptococcus phenolicus and the bacterium Peribacillus simplex as the sole source of nitrogen, paving the way for their potential use as biostimulants. Full article

In recent decades, there has been a significant decrease in humus resources in the terrestrial environment, including in agriculturally used soils, due to increased mineralisation of soil organic matter (SOM). Using composting as a method for recycling lignin-cellulosic biomass, the application of innovative microbial stimulation seems reasonable for obtaining the most useful product. The aim of this study was the qualitative and quantitative analysis of humic acids during the composting of exogenous organic matter (EOM) of energy willow biomass (WBC) and biodegradable municipal waste (MSWC). Samples were collected at different maturity stages, and the following determinations were performed: total organic carbon (TOC) and total nitrogen (TN), carbon of fulvic (CFA) and humic (CHA) acids, carbon of residual fraction (CR), the elemental composition of humic acids, humification index (HR₁), and ω (oxidation) ratios. Results indicated the direction and intensity of biotransformation processes were determined by the availability of nitrogen compounds. The innovative use of microbial preparation has resulted in a more useful final product. Inoculation of lignocellulosic substrates stimulated the synthesis of humic acids, and the decomposition of the CR fraction, as well as HR₁ and ω ratios, may be used to assess the recycling efficiency. Full article