Enzymatic conversion and recovery of protein, chitin, and astaxanthin from shrimp shell waste

Chitinases are a group of hydrolytic enzymes that catalyze chitin, nd are synthesized by a wide variety of organisms. In nature, microbial chitinases are primarily responsible for chitin decomposition. Several chitinases have been reported and characterized, and they are garnering increasing attention for their uses in a wide range of applications. In the food industry, the direct fermentation of seafood, such as crab and shrimp shells, using chitinolytic microorganisms has contributed to increased nutritional benefits through the enhancement of chitin degradation into chitooligosaccharides. These compounds have been demonstrated to improve human health through their antitumor, antimicrobial, immunomodulatory, antioxidant, and anti-inflammatory properties. Moreover, chitinase and chitinous materials are used in the food industry for other purposes, such as the production of single-cell proteins, chitooligosaccharides, N-acetyl D-glucosamines, biocontrol, functional foods, and various medicines. The functional properties and hydrolyzed products of chitinase, however, depend upon its source and physicochemical characteristics. The present review strives to clarify these perspectives and critically discusses the advances and limitations of microbial chitinase in the further production of functional foods.

Microbial chitinases: properties, current state and biotechnological applications.

Chitosanase (E.C. 3.2.1.132) can be used to selectively produce partially-acetylated chitosan oligosaccharides (COSs), which are functional biopolymers that can widely be utilized as environmentall...

Biocatalysis of Heterogenously-Expressed Chitosanase for the Preparation of Desirable Chitosan Oligosaccharides Applied against Phytopathogenic Fungi

Systems and synthetic biology to elucidate secondary metabolite biosynthetic gene clusters encoded in Streptomyces genomes.

The ongoing development of new production methods may lead to the commercialization of N-acetyl chitooligosaccharides (NACOS), such as chitosan oligosaccharides (COS). The bioactivity of NACOS, although not well detailed, differs from that of COS, as they have more acetyl groups than COS. We used two enzymatically produced NACOS with different molecular compositions and six NACOS (NACOS1–6) with a single degree of polymerization to verify their immunomodulatory effects on the RAW264.7 macrophage cell line. We aimed to identify any differences between COS and various NACOS with a single degree of polymerization. The results showed that NACOS had similar immune enhancement effects on RAW264.7 cells as COS, including the generation of reactive oxygen species (ROS), phagocytotic activity, and the production of pro-inflammation cytokines (IL-1β, IL-6, and TNF-α). However, unlike COS and lipopolysaccharide (LPS), NACOS1 and NACOS6 significantly inhibited nitric oxide (NO) production. Besides their immune enhancement effects, NACOS also significantly inhibited the LPS-induced RAW264.7 inflammatory response with some differences between various polymerization degrees. We confirmed that the NF-κB pathway is associated with the immunomodulatory effects of NACOS on RAW264.7 cells. This study could inform the application of NACOS with varying different degrees of polymerization in human health.

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Immunomodulatory Effects of N-Acetyl Chitooligosaccharides on RAW264.7 Macrophages.

Heterologous expression and characterization of an antifungal chitinase (Chit46) from Trichoderma harzianum GIM 3.442 and its application in colloidal chitin conversion.

Feather waste is the highest protein-containing resource in nature and is poorly reused. Bioconversion is widely accepted as a low-cost and environmentally benign process, but limited by the availability of safe and highly efficient feather degrading bacteria (FDB) for its industrial-scale fermentation. Excessive focuses on keratinase and limited knowledge of other factors have hindered complete understanding of the mechanisms employed by FDB to utilize feathers and feather cycling in the biosphere. Streptomyces sp. SCUT-3 can efficiently degrade feather to products with high amino acid content, useful as a nutrition source for animals, plants and microorganisms. Using multiple omics and other techniques, we reveal how SCUT-3 turns on its feather utilization machinery, including its colonization, reducing agent and protease secretion, peptide/amino acid importation and metabolism, oxygen consumption and iron uptake, spore formation and resuscitation, and so on. This study would shed light on the feather utilization mechanisms of FDBs.

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The feather degradation mechanisms of a new Streptomyces sp. isolate SCUT-3.

Promotion of feather waste recycling by enhancing the reducing power and keratinase activity of Streptomyces sp. SCUT-3

The invention provides acid protease Candidapepsin as well as a heterogeneous expression and purification method thereof. The acid protease Candidapepsin is sourced from candida tropicalis, an amino acid sequence of the acid protease Candidapepsin is as shown in SEQ ID NO.1, the enzyme activity of the acid protease Candidapepsin can be up to 268.2U/mL, and the specific enzyme activity can be up to2086.7U/mL and is far higher than the enzyme activity of like reported acid protease; the hydrolysis effect of the acid protease Candidapepsin is superior to that of commercial papain and commercialacid protease. The invention also provides the heterogeneous expression and purification method of the acid protease Candidapepsin. According to the heterogeneous expression and purification method provided by the invention, the yield of Candidapepsin protease is increased to a large extent, the yield can be up to 384.3mg/L, and a wide popularization and application prospect is obtained.

Acid protease Candidapepsin as well as heterogeneous expression and purification method thereof

The invention provides chitinase Chit46 as well as an expression and purification method and application thereof. The chitinase Chit46 is derived from trichoderma harzianum and an amino acid sequenceis shown as SEQ ID NO. 1; the fermentation solution enzyme activity of the chitinase is 31.4 U/mL and the specific enzyme activity is 34.5 U/mg, which is higher than that of like reported chitinase. The invention further provides the expression and purification method of the chitinase Chit46; the yield of the chitinase is greatly improved, the protein yield of a crude enzyme solution can reach 1.26 g/L and the yield of purified protein reaches 0.77 g/L. The chitinase provided by the invention can be used for hydrolyzing colloid chitin and has good hydrolysis activity; hydrolysis products are stable and the vast majority of hydrolysis products are chitobiose; a subsequent complicated purification and separation technology of each polymerization degree is omitted and the chitinase has a goodapplication prospect.

Liang Shuang

Papers

Heterologous expression and characterization of an antifungal chitinase (Chit46) from Trichoderma harzianum GIM 3.442 and its application in colloidal chitin conversion.

The feather degradation mechanisms of a new Streptomyces sp. isolate SCUT-3.

Promotion of feather waste recycling by enhancing the reducing power and keratinase activity of Streptomyces sp. SCUT-3

Acid protease Candidapepsin as well as heterogeneous expression and purification method thereof

Chitinase Chit46 as well as expression and purification method and application thereof