Search Results (28)

Ultrasonic-assisted heterogeneous Fenton-like (UHEF) pretreatment is an emerging strategy that overcomes the limitations of traditional homogeneous Fenton systems while enhancing the efficiency of lignocellulosic biomass processing. In this study, we constructed a UHEF system employing iron-loaded zeolite as a heterogeneous catalyst to pretreat eucalyptus sawdust (ES). Process conditions were optimized using response surface methodology (RSM) with a central composite design (CCD), yielding a maximum reducing sugar production of 441.45 mg/g. We systematically investigated the mechanism by which UHEF pretreatment enhances the enzymatic hydrolysis of ES through compositional analysis, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), cross-polarization magic-angle spinning carbon-13 nuclear magnetic resonance (CP/MAS ¹³C NMR), and scanning electron microscopy (SEM). Additionally, recovery and recycling experiments were conducted to evaluate the reusability of the iron-loaded zeolite. XRD, XPS, and ICP-OES were further used to verify the crystalline structure, surface Fe chemical states, and Fe loading of the catalyst, and Fe leaching was quantified for each reuse cycle. The results demonstrated that UHEF pretreatment effectively removed lignin and hemicellulose from ES, disrupted the cellulose crystalline structure, and generated numerous grooves on the substrate surface. These modifications increased the effective adsorption of cellulase and enhanced reducing sugar production to 4.32 times that of raw eucalyptus sawdust (RES). Although the recycling experiments indicated that the stability of the iron-loaded zeolite requires further improvement, the catalyst retained a certain degree of reusability over four consecutive cycles. These findings demonstrate that UHEF pretreatment is a promising approach with broad application prospects in lignocellulosic biorefinery, consistent with recent advances in advanced oxidation processes for biomass valorization. Full article

Spent mushroom substrate (SMS) is a major agricultural byproduct whose complex lignocellulosic matrix hinders direct reuse and poses environmental risks when stockpiled. This study evaluated whether pretreatment with plant growth-promoting rhizobacteria (PGPR) could enhance SMS as a soil amendment for blueberry cultivation. Two PGPR-treated SMS formulations, along with raw SMS and a blank control, were applied to blueberry seedlings in a 10-month greenhouse experiment. Plant height, rhizosphere soil nutrients, enzyme activities, lignocellulose fractions, and the microbial communities were monitored over three growth phases and four sampling points. PGPR-treated SMS significantly increased blueberry height gain during the fast-growing phase (June–September) and sustained elevated levels of organic carbon, nitrogen, phosphorus, and potassium throughout the experiment. Activities of cellulase, xylanase, laccase, peroxidase, protease, and lipase were markedly enhanced, accompanied by reduced lignin and cellulose contents and persistently high glucose availability. The amendments reshaped bacterial and fungal communities, enriching Bacillota, Acidobacteriota, Acidibacter, and Hyphomicrobium, and increasing alpha diversity, with clear structural separation from controls in principal coordinate analysis. Correlation and principal component analyses linked improved plant growth to nutrient availability, enzyme stimulation, and specific microbial taxa. These findings indicate that PGPR-treated SMS acts as a multifunctional amendment that promotes lignocellulose degradation, sustains soil fertility, and restructures the rhizosphere microbiome, offering a sustainable recycling strategy for horticultural production. Full article

This study investigated the effects of different Effective Microorganism (EM) inoculation concentrations (0%, 0.5%, 2%, 5%, 10%, 15%) on the co-composting of Auricularia heimuer residue with chicken manure and the subsequent growth of maize. The aim was to enhance composting efficiency and promote maize productivity. Results showed that EM addition, particularly at medium concentrations, significantly accelerated the composting process by shortening the heating phase and prolonging the thermophilic period, with the 10% treatment reaching >50 °C by day 2. The 5–10% EM treatments markedly promoted the degradation of cellulose and hemicellulose, and enhanced key enzyme activities (e.g., cellulase and hemicellulase) during composting and maize growth stages. Regarding soil nutrients, the 5% EM treatment led to the most balanced increases in total nitrogen (TN), total phosphorus (TP), and total potassium (TK) contents, with rises of 58.7%, 47.8%, and 130.4%, respectively, during the seedling stage. For maize yield, this treatment enhanced total grain weight, hundred-grain weight, and root activity by 25.7%, 30.9%, and 53.2%, respectively, while also increasing dry matter and root weight. Redundancy and correlation analyses indicated strong positive relationships among root activity, soil TN, cellulase activity, and final yield. In conclusion, EM inoculation at 5–10% optimizes the composting process, improves substrate quality and nutrient supply, and promotes maize root development and yield, with 5% EM offering the most comprehensive benefits. This study provides a practical approach for agricultural waste recycling and sustainable maize cultivation. Full article

Agricultural wastes such as sugar beet byproducts and corncobs face challenges including high fiber content and low microbe–substrate interaction efficiency during their storage and conversion into animal feed resources. This study evaluated the effects of Lentilactobacillus buchneri and cellulase supplementation on fermentation quality, microbial community structure, and the in vitro fermentation rate of mixed silage containing sugar beet tops and corncobs (air-dried). Sugar beet tops and corncobs were mixed at a fresh weight ratio of 9:1 and divided into three treatments—no additives (CK), Lentilactobacillus buchneri (LB, 1 × 10⁶ CFU·g⁻¹ Lentilactobacillus buchneri), Lentilactobacillus buchneri and cellulase (LBC, 1 × 10⁶ CFU·g⁻¹ Lentilactobacillus buchneri and 0.1 g kg⁻¹ cellulase)—and subjected to anaerobic fermentation for 60 days. The results showed that LB and LBC treatments reduced the losses of crude protein (CP) and water-soluble carbohydrate (WSC) (p < 0.05) and decreased the contents of neutral detergent fiber (NDF) and acid detergent fiber (ADF) (p < 0.05). Furthermore, LB and LBC treatments significantly increased the yields of lactic acid (by 31% and 46%, respectively) and acetic acid (by 60% and 78%, respectively) after anaerobic fermentation. Microbial community analysis revealed that Lactiplantibacillus (79~85%) was the dominant genus in both LB and LBC treatments, followed by Levilactobacillus (9~15%); however, principal coordinate analysis (PcoA) showed significant differences in bacterial communities between the LB and LBC treatment. The LBC treatment significantly enriched Levilactobacillus, which exhibited significant positive or negative correlations with multiple fermentation indicators. In addition, in vitro fermentation trial demonstrated that the silage treated with LBC showed higher in vitro dry matter digestibility (IVDMD) and better fermentation characteristics during in vitro fermentation (p < 0.05), with significantly increased total volatile fatty acids (TVFA) and butyric acid (BA) contents, and a decreased acetic acid content (p < 0.05). During in vitro fermentation, the LBC treatment had higher total gas production, as well as lower methane and carbon dioxide emissions (p < 0.05). Under the synergistic effect of Lentilactobacillus buchneri and cellulase, the fermentation quality and microbial community of sugar beet top–corncob silage are improved, thereby enhancing in vitro fermentation characteristics and providing insights for the recycling of agricultural wastes. Full article

Deinking is a key step in the recycling of waste paper. To address the problems of traditional chemical deinking, which generates large amounts of highly polluted wastewater and increases environmental pressure and treatment costs, as well as the issues of insufficient pulp brightness and high effective residual ink concentration (ERIC), a study on enzymatic deinking of old newsprint paper (ONP) was conducted. By optimizing the ratio of lipase, cellulase, amylase, and xylanase, a composite enzyme preparation for ONP deinking was successfully developed, and the corresponding deinking process was established. The composition of the composite enzyme preparation is as follows: Lipase 1.5 U/g oven-dried pulp (ODP), Cellulase 2 U/g ODP, Amylase 1.5 U/g ODP, and Xylanase 2 U/g ODP. When the composite enzyme preparation was used for enzymatic deinking, compared with chemical deinking, the brightness increased by 3.52% ISO, ERIC decreased by 9.12 ppm, and the physical properties of the paper were improved to varying degrees. The deinking efficiency was significantly superior to that of chemical deinking, while the usage of chemical reagents was effectively reduced. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were further used to investigate the effect of the composite enzyme on fiber structure and its possible synergistic mechanism: the surface structure and hydrogen bond network of fibers were altered, thereby reducing the content of chromophores such as hydroxyl, carbonyl, and benzene ring groups as well as residual lignin, and facilitating the separation of ink from the fiber surface. This study provides support for the development of an environmentally friendly waste paper recycling process and contributes to promoting the sustainable development of the papermaking industry. Full article

This study reveals how microbial diversity relates to soil properties in Auricularia heimuer residue–chicken manure composting, presenting sustainable waste recycling solutions. These microbial-straw strategies are adaptable to various agroecological regions, offering flexible residue valorization approaches for local conditions, crops, and resources. This study examined the effects of composting Auricularia heimuer residue and chicken manure at three ratios (6:4, 7:3, 8:2) on soil properties, lignocellulose content, enzyme activity, microbial diversity, and maize growth. The compost was mixed into potting soil at different proportions (0:10 to 10:0). During composting, the temperature remained above 50 °C for more than 14 days, meeting safety and sanitation requirements. The composting process resulted in a pH range of 7–8, a stable moisture content of 60%, a color change from brown to gray-brown, the elimination of unpleasant odors, and the formation of loose aggregates. Lignocellulose content steadily decreased, while lignocellulosic enzyme activity and actinomycete abundance increased, indicating suitability for field application. Compared with the control (CK), total nitrogen, total phosphorus, and total potassium in the soil increased by 57.81–77.91%, 4.5–19.28%, and 301.09–577.2%, respectively. Lignin, cellulose, and hemicellulose increased 50.6–83.49%, 59.6–340.33%, and 150.86–310.5%, respectively. The activities of lignin peroxidase, cellulase, and hemicellulase increased by 9.05–36.31%, 6.7–36.66%, and 37.39–52.16%, respectively. Maize root weight, plant biomass, and root number increased by 120.87–138.59%, 117.83–152.86%, and 29.03–75.81%, respectively. In addition, composting increased the relative abundance of actinomycetes while decreasing the abundance of ascomycetes and ascomycetes. The relative abundance of Sphingomonas and Gemmatimonas increased, whereas pathogenic fungi such as Cladosporium and Fusarium decreased. Compost application also enhanced bacterial and fungal diversity, with bacterial diversity indices ranging from 6.744 to 9.491 (B1), 5.122 to 9.420 (B2), 8.221 to 9.552 (B3), and 6.970 to 9.273 (CK). Fungal diversity indices ranged from 4.811 to 8.583 (B1), 1.964 to 9.160 (B2), 5.170 to 9.022 (B3), and 5.893 to 7.583 (CK). Correlation analysis of soil physicochemical properties, lignocellulose content, enzymes, microbial community composition, and diversity revealed that total nitrogen, total phosphorus, total potassium, and lignocellulose content were the primary drivers of rhizosphere microbial community dynamics. These factors exhibited significant correlations with the dominant bacterial and fungal taxa. Additionally, bacterial and fungal diversity increased with the incorporation of Auricularia heimuer residue. In conclusion, this study elucidates the relationships between microbial diversity and soil properties across different proportions of Auricularia heimuer residue and chicken manure composting, offering alternative strategies for waste recycling and sustainable agricultural development. At present, the production of biobiotics using waste culture microorganisms is still in the laboratory research stage, and no expanded experiments have been carried out. Therefore, how to apply waste bacterial bran to the production of biocontrol biotics on a large scale needs further research. Full article

The enzymatic hydrolysis process is important in the field of textile waste reuse in the circular economy context. Currently, enzymatic cellulase treatment of waste textiles, such as bamboo mixture with spandex samples (BS), cotton jeans (CJ), linen (L), and cotton T-shirts (CT), has been tested, in which glucose production was measured at the presence of 6 and 8% NaOH solution. The characteristics of the textiles and hydrolysis capacity were evaluated by the amount of glucose (g) obtained from each textile. The following indicators were also measured during the experiment: temperature, pH, enzymatic cellulase solution composition, final glucose concentrations, turbidity, and color intensity. The temperature of the mixture was maintained at 50 °C, and a pH level of 5–7 along with a contact time of 48–94 min were controlled. The experiments demonstrated that when the enzymatic hydrolysis was active, turbidity increased from 86 nephelometric turbidity unit (NTU) to >1000 NTU; the color of the hydrolyzed samples was obtained from 86 NTU to >1000 NTU; and the final glucose concentration was approximately between 0.49 and 33.9 mmol/L for L, CT, and CJ samples measured to produce up to one gram of glucose from 3.330 g of textile, and a BS samples produced one gram of glucose from 3.164 g of textile. The findings show that recycled glucose obtained from textile waste materials is environmentally sustainable. Such textile waste can then be reused rather than being dumped in already overloaded landfills. Full article

Succinic acid is applied in many chemical industries in which it can be produced through microbial fermentation using lignocellulosic biomasses. Mixed-waste office paper (MWOP) containing lignocellulosic fibers is enormously generated globally. MWOP is recycled into toilet paper and cardboard, but the recovery process is costly. The reuse of MWOP to alternatively produce succinic acid is highly attractive. In this study, pretreatment of MWOPs with 1% (v/v) H₂SO₄ at 121 °C for 20 min was found to be optimal. The optimal conditions for the enzymatic hydrolysis of H₂SO₄-pretreated MWOP (AP-MWOP) were at 50 °C, with cellulase loading at 80 PCU/g AP-MWOP. This resulted in the highest glucose (22.46 ± 0.15 g/L) and xylose (5.11 ± 0.32 g/L). Succinic acid production via separate hydrolysis and fermentation (SHF) by Escherichia coli KJ122 reached 28.19 ± 0.98 g/L (productivity of 1.17 ± 0.04 g/L/h). For simultaneous saccharification and fermentation (SSF), succinic acid was produced at 24.58 ± 2.32 g/L (productivity of 0.82 ± 0.07 g/L/h). Finally, succinic acid at 51.38 ± 4.05 g/L with yield and productivity of 0.75 ± 0.05 g/g and 1.07 ± 0.08 g/L/h was achieved via fed-batch pre-saccharified SSF. This study not only offers means to reuse MWOP for producing succinic acid but also provides insights for exploiting other wastes to high-value succinic acid, supporting environmental sustainability and zero-waste society. Full article

There are millions of tons of fresh soy sauce residue (SSR) by-products created by China’s soy sauce industry every year. Most of the SSR is directly discarded; this not only wastes resources, but also pollutes the environment. As it is rich in dietary fiber, which is beneficial to human health, skimmed SSR was used as a raw material to obtain soluble dietary fiber (SDF) in this study. Firstly, the process of ultrasonic-assisted enzymatic extraction of SDF was optimized through single factor experiments and a response surface test. The extraction rate of the SDF from SSR reached 76.8 ± 0.8% under the optimum extracting conditions of a cellulase/hemicellulase (w/w) 1/1 mixture, an enzyme addition amount of 5.7%, a material–liquid ratio (w/v) of 1/20 g/mL, and a reaction time of 30 min. Then, the physicochemical properties of the SDF extracted using enzymatic and chemical methods were compared; we found that the SDF obtained through ultrasound-assisted enzymatic extraction had a much better appearance and physicochemical properties than that extracted by acid or alkali, with a lighter color, higher extraction rate, higher water-holding capacity, higher oil-holding capacity, higher swelling capacity, and solubility. The microstructure was more uniform and porous. This study will provide theoretical guidance and technical support for the recycling and utilization of SSR, which is beneficial for improving its economic value. Full article

Hydrolases are the most popular enzymes, and among the most valuable in biotechnological applications. Some hydrolases, such as lipases, esterases, proteases, cellulases and amylases, are used in the food industry and the production of biopharmaceuticals, biofuels, biopolymers and detergents. Of special interest are those obtained from thermophilic microorganisms. Although there is great microbial diversity in extreme environments, the investigations aimed at detecting and isolating enzymes with potential for polyester degradation such as polyethylene terephthalate (PET) are limited. In this work, we explored the metagenomic library of an oil-enriched soil sample from the “Los Humeros” geothermal field by means of in silico probes in search for enzymes potentially able to degrade polyesters. Using conserved motifs and activity-relevant sites of reported polyester hydrolases, we designed probes that allowed us to identify 6 potential polyester hydrolases in the metagenome. Three-dimensional structure prediction revealed a canonical α/β fold and a cap covering the active site of the enzymes. The catalytic triads were composed of Ser, His and Asp. Structural comparison, substrate binding site analysis and molecular docking suggested their potential as polyester hydrolases, particularly cutinases and PETases. An enzyme, REC98271, was cloned, expressed and characterized, showing thermophilic properties and preference for short-chain substrates. These findings contribute to our understanding of enzyme diversity in “Los Humeros” metagenome and their potential applications in biodegradation and recycling processes. Full article

This paper reports an innovative study that aims to address key issues in the efficient recycling of wastepaper cellulose. The research team utilized the temperature-responsive upper critical solution temperature (UCST) polymer P(NAGA-b-DMA) in combination with the LytA label’s affinity for choline analogs. This innovative approach enabled them to successfully develop a novel soluble immobilized enzyme, P(NAGA-b-DMA)-cellulase. This new enzyme has proven highly effective, significantly enhancing the degradation of wastepaper cellulose while demonstrating exceptional stability. Compared with the traditional insoluble immobilized cellulase, the enzyme showed a significant improvement in the pH, temperature stability, recycling ability, and storage stability. A kinetic parameter calculation showed that the enzymatic effectiveness of the soluble immobilized enzyme was much better than that of the traditional insoluble immobilized cellulase. After the immobilization reaction, the Michaelis constant of the immobilized enzyme was only increased by 11.5%. In the actual wastepaper degradation experiment, the immobilized enzyme was effectively used, and it was found that the degradation efficiency of wastepaper cellulose reached 80% of that observed in laboratory conditions. This novel, thermosensitive soluble immobilized cellulase can efficiently catalyze the conversion of wastepaper cellulose into glucose under suitable conditions, so as to further ferment into environmentally friendly biofuel ethanol, which provides a solution to solve the shortage of raw materials and environmental protection problems in the paper products industry. Full article

Polyester/cotton fabrics with different proportions of Tetron Cotton, TC (35% Cotton/65% PET), and Chief Value Cotton, CVC (60% Cotton/40% PET), were investigated by removing the cotton component under various phosphoric acidic conditions including the use of cellulase enzymes. The remaining polyethylene terephthalate (PET) component was spun using the melt spinning method. Only 85% H₃PO₄-Enz_TC could be spun into consistent filament fibers. The effects of Acid-Enz TC (obtained from a powder preparation of 85% H₃PO₄-Enz_TC) at different weight amounts (1, 2, 5, and 10 %wt) blending with WF-rPET powder prepared by white recycled polyester fabric were evaluated for fiber spinnability at different winding speeds of 1000 and 1500 m/min. The results revealed that recycled PET fiber spun by adding Acid-Enz_TC up to 10 %wt gave uniformly distributed filament fibers. A comparative study of the physical, thermal, and mechanical properties also investigated the relationship between the effect of Acid-Enz_TC and the structure of the obtained fibers. Acid-Enz_TC:WF-rPET (5:95) was the optimal ratio. The thermal values were analyzed by DSC and TGA and crystallinity was analyzed by XRD, with mechanical strength closed to 100% WF-rPET. The FTIR analysis of the functional groups showed the removal of cotton from the blended fabrics. Other factors such as the Acid-Enz_TC component in WF-rPET, extraction conditions, purity, thermal, chemical, and exposure experiences also affected the formability and properties of recycled PET made from non-single-component raw materials. This study advanced the understanding of recycling PET from TC fabrics by strategically removing cotton from polyester–cotton blends and then recycling using controlled conditions and processes via the melt spinning method. Full article

Food safety and quality are major problems for food producers and industry, governments, and consumers. Conventional plastic-based food packaging is difficult to dispose of and recycle due to its provenience from fossil resources and resistance to biodegradation. Therefore, currently, the trend is to develop new eco-friendly food packaging that can replace these materials. The limitations of conventional packaging can be solved by developing new active materials with antimicrobial and antioxidant properties, based on cellulose, a natural biodegradable organic compound derived from renewable resources. In this study, new materials with antioxidant and antibacterial activity were obtained by combining a “green” functionalization approach (enzymatic activation) and surface modification using bioactive agents (essential clove oil and cold-pressed grape seed oil). Kraft paper was firstly activated with cellulase, followed by impregnation with the above-mentioned oil solutions, and then its properties were evaluated. The increased values of the O/C ratio for modified Kraft paper indicate an increased polarity due to the presence of phenolic groups. This resulted in an improved hydrophobicity, with the water contact angle increasing from 97° to over 110°. Following different interactions with the functional groups of vegetable oils, the modified Kraft paper exhibited distinct antioxidant and antibacterial properties. However, modified paper with clove essential oil showed higher antioxidant activity (due to the higher content of phenolic compounds), while modified paper with cold-pressed grape seed oil had better antimicrobial activity against Escherichia coli (−), Salmonella enteritidis (−), and Listeria monocytogenes (+) bacterial strains, and was more effective at reducing bacterial growth on fresh beef and fresh curd. The newly obtained bioactive paper provides an effective packaging material that can help control foodborne pathogens in food, thus extending its shelf life and safety. Full article

Food processing wastes (FPWs) are residues generated in food manufacturing, and their composition varies depending on the type of food product being manufactured. Therefore, selecting and acclimatizing seed microflora during the initiation of biogas production is crucial for optimal outcomes. The present study examined the biogas production capabilities of digested sludge-assimilating and biogas-yielding soil (DABYS) and enteric (DABYE) microflorae when used as seed cultures for biogas production from FPWs. After subculturing and feeding these microbial seeds with various FPWs, we assessed their biogas-producing abilities. The subcultures produced biogas from many FPWs, except orange peel, suggesting that the heterogeneity of the bacterial members in the seed microflora facilitates quick adaptation to FPWs. Microflorae fed with animal-derived FPWs contained several methanogenic archaeal families and produced methane. In contrast, microflorae fed with vegetable-, fruit-, and crop-derived FPWs generated hydrogen, and methanogenic archaeal populations were diminished by repeated subculturing. The subcultured microflorae appear to hydrolyze carbohydrates and protein in FPWs using cellulase, pectinase, or protease. Despite needing enhancements in biogas yield for future industrial scale-up, the DABYS and DABYE microflorae demonstrate robust adaptability to various FPWs. Full article

This research explored the effects of the addition of low doses of aromatic plant biomasses (APBs) on the microbial community and carbon source decomposition in compost. APBs were reported to be capable of altering the composition and function of microbial communities in many environments. However, the effects of APB addition on the compost carbon source metabolism, a process highly linked to the microbial community of compost, were still unclarified, especially when added in small doses. In this study, Cinnamomum camphora biomass was added to the initial compost of Stropharia rugosoannulata cultivation materials, in a mass ratio of 0%, 1%, 2%, and 3%, respectively. The variation in the carbon source contents, the microbial community composition, and the related enzyme activities of the end compost products were measured. The results showed that Cinnamomum camphora biomass addition significantly altered the content of cellulose, hemicellulose, lignin, and protein of compost products, but did not affect the starch and soluble sugar content. Meanwhile, the addition significantly reduced lignin peroxidase and cellulase activities, but increased xylanase and laccase activities, and had no effect on magnesium peroxidase and polyphenol oxidase. Both the bacterial and fungal community compositions were significantly altered by the addition, though the alpha diversity indexes were not significantly changed. The relative abundance of Proteobacteria and Sordariomycetes was significantly increased by the addition, while Acidobacteria, Chloroflexi and Eurotiomycetes significantly decreased. Structural equation modeling found that the variation in the bacterial community composition (0.464 standard total effect) provided a higher contribution to lignocellulose degradation, rather than the fungal community (0.365 standard total effect). A co-occurrence network analysis further revealed that the trade-off between lignin peroxidase and laccase activity, which was induced by the relative abundance variation in Proteobacteria, Actinobacteriota, and Firmicute members, was the main driver in the lignocellulose decomposition variation. This research provides a new insight into the recycling of APB waste, and offers an improvement to mushroom cultivation material compost. Full article