Collagen contains abundant cell binding motifs, which are conducive to adhesion, migration, and differentiation, maintain cell vitality and promote cell proliferation. However, pure collagen hydrogel has some shortcomings such as poor mechanical properties, poor thermal stability and fast degradation. Numerous studies have shown that the properties of collagen can be improved by combining it with natural polysaccharides such as alginate, chitosan, hyaluronic acid and cellulose. In this paper, the research status and biological application fields of four kinds of composite hydrogels, including collagen-alginate composite hydrogels, collagen-chitosan hydrogels, collagen-hyaluronic acid hydrogels and collagen-cellulose hydrogels, were summarized. The common preparation methods of four kinds of composite hydrogels were introduced, and the future development direction of collagen-based composite hydrogels was prospected.
Hydrogels/chemical synthesis* ; Collagen/chemistry* ; Polysaccharides/chemistry* ; Alginates/chemistry* ; Hyaluronic Acid/chemistry* ; Chitosan/chemistry* ; Biocompatible Materials/chemistry* ; Humans ; Tissue Engineering/methods* ; Cellulose/chemistry* ; Tissue Scaffolds

Recently, returning straw to the fields has been proved as a direct and effective method to tackle soil nutrient loss and agricultural pollution. Meanwhile, the slow decomposition of straw may harm the growth of the next crop. This study aimed to determine the effects of rumen microorganisms (RMs) on straw decomposition, bacterial microbial community structure, soil properties, and soil enzyme activity. The results showed that RMs significantly enhanced the degradation rate of straw in the soil, reaching 39.52%, which was 41.37% higher than that of the control on the 30th day after straw return. After 30 d, straw degradation showed a significant slower trend in both the control and the experimental groups. According to the soil physicochemical parameters, the application of rumen fluid expedited soil matter transformation and nutrient buildup, and increased the urease, sucrase, and cellulase activity by 10%‒20%. The qualitative analysis of straw showed that the hydroxyl functional group structure of cellulose in straw was greatly damaged after the application of rumen fluid. The analysis of soil microbial community structure revealed that the addition of rumen fluid led to the proliferation of Actinobacteria with strong cellulose degradation ability, which was the main reason for the accelerated straw decomposition. Our study highlights that returning rice straw to the fields with rumen fluid inoculation can be used as an effective measure to enhance the biological value of recycled rice straw, proposing a viable solution to the problem of sluggish straw decomposition.
Animals ; Rumen/metabolism* ; Agriculture/methods* ; Soil/chemistry* ; Microbiota ; Bacteria/metabolism* ; Oryza/metabolism* ; Soil Microbiology ; Cellulose

Gluconacetobacter xylinus is a primary strain producing bacterial cellulose (BC). In G. xylinus, BcsD is a subunit of cellulose synthase and is participated in the assembly process of BC. A series of G. xylinus with different expression levels of the bcsD gene were obtained by using the CRISPR/dCas9 technique. Analysis of the structural characteristics of BC showed that the crystallinity and porosity of BC changed with the expression of bcsD. The porosity varied from 59.95%-84.05%, and the crystallinity varied from 74.26%-93.75%, while the yield of BC did not decrease significantly upon changing the expression levels of bcsD. The results showed that the porosity of bacterial cellulose significantly increased, while the crystallinity was positively correlated with the expression of bcsD, when the expression level of bcsD was below 55.34%. By altering the expression level of the bcsD gene, obtaining BC with different structures but stable yield through a one-step fermentation of G. xylinus was achieved.
Cellulose/chemistry* ; Clustered Regularly Interspaced Short Palindromic Repeats ; Fermentation ; Gluconacetobacter xylinus/metabolism*

Avicel is made of a mixture of microcrystalline cellulose (MCC) and carboxymethyl cellulose (CMC), and used for virus plaque assay. The avicel in common use is produced by FMC Biopolymer. Due to the relatively fixed proportion of MCC and CMC, avicel in common use is not suitable for plaque determination experiment of all types of viruses. In this study, we evaluated the effect of avicel made of different proportions of MCC and CMC on virus plaque assay, and developed an improved avicel virus plaque assay featured with simple and convenient operation, good practicability and high stability. To generate avicel overlays with different proportions of MCC and CMC, twelve different 2×avicel solutions were prepared. Their overall viscosity and bottom viscosity were measured to evaluate the ease of operation. The results showed that most of the 2×avicel solutions (except the 4.8% MCC+1.4% CMC and 4.8% MCC+1.0% CMC group) were easy to absorb and prepare nutrient overlap than 2×CMC solution. In order to find the best scheme to detect the titer of porcine epidemic diarrhea virus (PEDV), these avicel overlay solutions with different proportion of MCC and CMC were used as a replacement in the standard plaque assay. By comparing the size, clarity, stability and titer accuracy of virus plaque, we identified that 0.6% MCC and 0.7% CMC was the most preferable composition of avicel overlay for PEDV plaque assay. In conclusion, we developed an improved virus plaque assay based on avicel, which may facilitate the research of virus etiology, antiviral drugs and vaccines.
Animals ; Carboxymethylcellulose Sodium/chemistry* ; Cellulose/chemistry* ; Swine

The shortage of medical resources promotes medical treatment reform, and smart healthcare is a promising strategy to solve this problem. With the development of Internet, real-time health status is expected to be monitored at home by using flexible healthcare systems, which puts forward new demands on flexible substrates for sensors. Currently, the flexible substrates are mainly traditional petroleum-based polymers, which are not renewable. As a natural polymer, cellulose, owing to its wide range of sources, convenient processing, biodegradability and so on, is an ideal alternative. In this review, the application progress of nanocellulose in flexible sensors is summarized. The structure and the modification methods of cellulose and nanocellulose are introduced at first, and then the application of nanocellulose flexible sensors in real-time medical monitoring is summarized. Finally, the advantages and future challenges of nanocellulose in the field of flexible sensors are discussed.
Cellulose/chemistry* ; Hydrogels/chemistry* ; Polymers

Residue of Mori Cortex was studied to optimize its enzymatic hydrolysis process, and explore its potential as a carbon source for biochemistry and biofuel production. The cellulose content of diluted acid pretreated (DAP) and non-pretreated from Mori Cortex were measured in this study, and the results showed that the cellulose content of DAP and non-pretreated from Mori Cortex were 52.5% and 47%, respectively. This higher cellulose content indicated that residue of Mori Cortex had the potential to act as a carbon source for biochemistry and biofuel production. Enzymatic hydrolysis of pretreated and non-pretreated from Mori Cortex was conducted under different enzyme loading amount. 40 FPU·(g DW）⁻¹ enzyme loading was determined as the optimal amount by comparing the yield of sugar and the rate of enzymolysis. Under this condition, the concentrations of glucose, xylose, arabinose sugar were 23.82, 4.84, 3.6 g·L⁻¹, and the corresponding enzymatic hydrolysis rate was 45.33% which was 2.3 times higher than that of non-pretreated from Morus alba residues. Fed-batch enzymatic hydrolysis was conducted finally to get higher sugar yield, and the final glucose concentration reached up to 38 g·L⁻¹ with the enzymatic hydrolysis rate of 36.19%. The results indicated that Mori Cortex residue had higher cellulose and hemicellulose contents, so it had the potential to become a carbon source to produce the bio-chemicals and biofuels. Through enzymatic hydrolysis, it can be converted into microbial available monosaccharides; and through fermentation, it can be converted into high value-added chemicals, biofuels, etc., to solve the problem of residue pollution, and achieve the sustainable development and greening of Chinese pharmaceutical production process.
Carbohydrates ; Cellulose ; chemistry ; Enzymes ; metabolism ; Fermentation ; Hydrolysis ; Morus ; chemistry

Cellulosic ethanol, with the advantages of renewable resource, cleanliness and safety, is the mainstream of new energy development and has obtained extensive attention worldwide. In this review, the biological characteristics of beets were introduced, and then the superiority and application progress of beets and its by-product sugar beet pulp in the bioethanol production were stated. At last, cellulosic ethanol production coupled with the component separation and comprehensive utilization of beet pulp was proposed.
Beta vulgaris ; chemistry ; Biofuels ; Cellulose ; chemistry ; Ethanol ; chemistry

The expensive production of bioethanol is because it has not yet reached the 'THREE-HIGH' (High-titer, high-conversion and high-productivity) technical levels of starchy ethanol production. To cope with it, it is necessary to implement a high-gravity mash bioethanol production (HMBP), in which sugar hydrolysates are thick and fermentation-inhibitive compounds are negligible. In this work, HMBP from an atmospheric glycerol autocatalytic organosolv pretreated wheat straw was carried out with different fermentation strategies. Under an optimized condition (15% substrate concentration, 10 g/L (NH4)2SO4, 30 FPU/g dry matter, 10% (V/V) inoculum ratio), HMBP was at 31.2 g/L with a shaking simultaneous saccharification and fermentation (SSF) at 37 degrees C for 72 h, and achieved with a conversion of 73% and a productivity of 0.43 g/(L x h). Further by a semi-SFF with pre-hydrolysis time of 24 h, HMBP reached 33.7 g/L, the conversion and productivity of which was 79% and 0.47 g/(L x h), respectively. During the SSF and semi-SSF, more than 90% of the cellulose in both substrates were hydrolyzed into fermentable sugars. Finally, a fed-batch semi-SFF was developed with an initial substrate concentration of 15%, in which dried substrate (= the weight of the initial substrate) was divided into three portions and added into the conical flask once each 8 h during the first 24 h. HMBP achieved at 51.2 g/L for 72 h with a high productivity of 0.71 g/(L x h) while a low cellulose conversion of 62%. Interestingly, the fermentation inhibitive compound was mainly acetic acid, less than 3.0 g/L, and there were no other inhibitors detected, commonly furfural and hydroxymethyl furfural existing in the slurry. The data indicate that the lignocellulosic substrate subjected to the atmospheric glycerol autocatalytic organosolv pretreatment is very applicable for HMBP. The fed-batch semi-SFF is effective and desirable to realize an HMBP.
Biofuels ; Carbohydrates ; chemistry ; Cellulose ; chemistry ; Ethanol ; metabolism ; Fermentation ; Furaldehyde ; chemistry ; Glycerol ; chemistry ; Hydrolysis ; Triticum

In order to explore the possibility of Jerusalem artichoke stalk for bioenergy conversion, we analyzed the main composition of whole stalk, pitch, and core of the stalk. Meanwhile, these parts were pretreated with different NaOH concentrations at 121 degrees C. Afterwards, enzymatic hydrolysis was performed to evaluate the pretreatment efficiency. Jerusalem artichoke stalk was characterized by relatively high lignin content (32.0%) compared with traditional crop stalks. The total carbohydrate content was close to that of crop stalks, but with higher cellulose content (40.5%) and lower hemicellulose (19.6%) than those of traditional crop stalks. After pretreatment, the lignin content in the whole stalk, pitch, and core decreased by 13.1%-13.4%, 8.3%-13.5%, and 19.9%-27.2%, respectively, compared with the unpretreated substrates. The hemicellulose content in the whole stalk, pitch, and core decreased 87.8%-96.9%, 87.6%-95.0%, and 74.0%-90.2%, respectively. Correspondingly, the cellulose content in the pretreated whole stalk, pitch, and core increased by 56.5%-60.2%, 52.2%-55.4%, and 62.7%-73.2%, respectively. Moreover, increase of NaOH concentration for pretreatment could improve the enzymatic hydrolysis of the whole stalk and pitch by 2.3-2.6 folds and 10.3-18.5 folds, respectively. The hydrolysis of pretreated stalk core decreased significantly as 2.0 mol/L NaOH was employed, although the increased NaOH concentration can also improve its hydrolysis performance. Based on these results, hot-NaOH can be regarded as an option for Jerusalem artichoke stalk pretreatment. Increasing NaOH concentration was beneficial to hemicellulose and lignin removal, and consequently improved sugar conversion. However, the potential decrease of sugar conversion of the pretreated core by higher NaOH concentration suggested further optimization on the pretreatment conditions should be performed.
Biofuels ; Cellulose ; chemistry ; Helianthus ; chemistry ; Hot Temperature ; Hydrolysis ; Lignin ; chemistry ; Plant Stems ; chemistry ; Polysaccharides ; chemistry ; Sodium Hydroxide ; chemistry

Curcumin-ethyl-cellulose (EC) sustained-release composite particles were prepared by using supercritical CO2 anti-solvent technology. With drug loading and yield of inclusion complex as evaluation indexes, on the basis of single factor tests, orthogonal experimental design was used to optimize the preparation process of curcumin-EC sustained-release composite particles. The experiments such as drug loading, yield, particle size distribution, electron microscope analysis (SEM) , infrared spectrum (IR), differential scanning calorimetry (DSC) and in vitro dissolution were used to analyze the optimal process combination. The orthogonal experimental optimization process conditions were set as follows: crystallization temperature 45 degrees C, crystallization pressure 10 MPa, curcumin concentration 8 g x L(-1), solvent flow rate 0.9 mL x min(-1), and CO2 velocity 4 L x min(-1). Under the optimal conditions, the average drug loading and yield of curcumin-EC sustained-release composite particles were 33.01% and 83.97%, and the average particle size of the particles was 20.632 μm. IR and DSC analysis showed that curcumin might complex with EC. The experiments of in vitro dissolution showed that curcumin-EC composite particles had good sustained-release effect. Curcumin-EC sustained-release composite particles can be prepared by supercritical CO2 anti-solvent technology.
Carbon Dioxide ; chemistry ; Cellulose ; administration & dosage ; analogs & derivatives ; chemistry ; Curcumin ; administration & dosage ; chemistry ; Delayed-Action Preparations ; Solubility ; Solvents ; Technology, Pharmaceutical