1.Enzymatic depolymerization of polyester-cotton textiles for the recovery of terephthalic acid.
Hongzhao WANG ; Yuntao CUN ; Minxuan WANG ; Zhenwu YANG ; Hao HE ; Yushan ZHU
Chinese Journal of Biotechnology 2025;41(9):3553-3566
Polyethylene terephthalate (PET) fibers are characterized by exceptional mechanical strength, and textiles blended with cotton fibers combine both comfort and durability, showcasing widespread use in daily applications. However, improper disposal of discarded polyester-cotton textiles has resulted in severe environmental pollution, necessitating urgent and effective mitigation strategies. Enzymatic recycling of textiles offers superior environmental benefits and holds greater potential for industrial applications than alternative recycling methods. This study aims to explore a large-scale solution for the treatment of waste textiles, particularly addressing the challenge of resource recovery from polyester-cotton blended fabrics. An innovative enzymatic depolymerization process has been developed to achieve the recovery of high-purity terephthalic acid monomers. Experiments were conducted on three different textile blends with polyester-to-cotton ratios of 65/35, 70/30, and 80/20, and the influences of different colors on the process were investigated. Initially, the textiles were pretreated through mechanical grinding, which was followed by depolymerization of cotton fibers with commercial cellulase. The crystallinity of PET in the textiles was reduced through a rapid heating and cooling process. Subsequently, the PET was depolymerized by the engineered PET hydrolase. The results demonstrated that after decolorization and separation of terephthalic acid (TPA) from the reaction system, the monomer recovery rates for the three textile blends (65/35, 70/30, and 80/20) reached 90%, 91%, and 92%, respectively. Characterization analysis by nuclear magnetic resonance (NMR) confirmed that the purity of the recovered TPA was greater than 99%. In conclusion, the fully enzymatic recycling process developed in this study shows considerable promise for large-scale industrial applications and is anticipated to significantly advance the adoption and development of enzymatic recycling technologies for PET in industrial processes.
Phthalic Acids/chemistry*
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Polyesters/chemistry*
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Textiles
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Cotton Fiber
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Polyethylene Terephthalates/chemistry*
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Cellulase/chemistry*
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Recycling/methods*
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Polymerization
2.The action of aquaporins in cell elongation, salt stress and photosynthesis.
Chinese Journal of Biotechnology 2009;25(3):321-327
Aquaporin belongs to a highly conserved group of membrane proteins called major intrinsic proteins (MIPs) that facilitate water transport across biological membranes. Aquaporins are membrane water channels that play critical roles in controlling the water content of cells and tissues. We focused on GhPIP1;2 which belongs to the PIP subfamily and GhgammaTIP1 which belongs to the gammaTIP group of the TIP subfamily. Northern blot analysis with gene-specific probes and real-time PCR demonstrated that GhPIP1;2 and GhgammaTIP1 are predominantly expressed during cotton fiber elongation, with the highest expression levels at 5 days post anthesis. The high and preferential expression of GhPIP1;2 and GhgammaTIP1 suggests that they may play important roles in supporting the rapid influx of water into vacuoles during cotton fiber cell expansion. Also, the effects of Ca2+ on aquaporins in salinity-stressed plants were studied. Researchers treated the protoplasts and plasma membrane with NaCl or CaCl2, alone or in combination. Under saline conditions, osmotic water permeability (Pf) values decreased in protoplasts and plasma membrane vesicles, and the same reduction was observed in the PIP1 aquaporin abundance, indicating inhibitory effects of NaCl on aquaporin functionality and protein abundance. Two different actions of Ca2+ were observed. Increase in free cytosolic calcium concentrations associated with stress perception may lead to aquaporin closure, however, the extra-calcium would lead to an upregulation of aquaporins. Meanwhile, experiments have demonstrated HvPIP2;1, one of barley aquaporins, has a higher water and CO2 transport activity. The goal of our plant aquaporin research is to determine the key aquaporin species responsible for water and CO2 transport, and to improve plant water relations, stress tolerance, CO2 uptake or assimilation, and plant productivity.
Aquaporins
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physiology
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Cell Enlargement
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Cotton Fiber
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Gossypium
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metabolism
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physiology
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Photosynthesis
;
physiology
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Plant Proteins
;
physiology
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Sodium Chloride
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pharmacology
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Stress, Physiological
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physiology
3.Existant quality problems and suggestions for quality control of medical absorbent cotton.
De-long JIANG ; An-zheng CHI ; Qi-hua ZHANG
Chinese Journal of Medical Instrumentation 2005;29(5):364-365
In the process of acid hydrolysis of medical absorbent cotton, we have discovered that some of the domestic manufactured medical absorbent cotton is mixed with wasted non-cotton chemical fiber. If the cotton is used in medical treatments, the chemical fiber will cause irritation, allergy and inflammation, so it's very harmful. But the non-cotton fiber content is not stipulated in the standard of YY0330-2002, and no testing method for it is available. In this paper we discuss the existent quality problems, the control and the test method for non-cotton chemical fiber in medical absorbent cotton.
Bandages
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standards
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Cotton Fiber
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Quality Control
4.Identification of genes that are specifically/preferentially expressed in developing cotton fibers by mRNA fluorescence differential display (FDD).
Jie SUN ; Yuan-Li LI ; Ruo-Hai WANG ; Gui-Xian XIA
Chinese Journal of Biotechnology 2004;20(1):39-42
Fluorescence differential display (FDD) technique was used to identify genes that are specifically or preferentially expressed in different developmental stages of cotton fiber cells. One hundred and nine differentially displayed cDNA fragments were isolated using 9, 21 and 27 DPA (days postanthesis) fibers as experimental materials. By a combination of two rounds of reverse Northern hybridization and Northern blot analyses, a number of such cDNA fragments were proved to represent fiber-specific/preferential genes. Sequencing determination and database searching indicated that most of these genes are novel. This work is an important step towards cloning the full-length cDNAs and characterizing the cellular functions of aforementioned genes in fiber development.
Blotting, Northern
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Cotton Fiber
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Fluorescence
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Gene Expression Profiling
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methods
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Gossypium
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genetics
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growth & development
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Polymerase Chain Reaction

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