Deproteinization Rate Research Articles

Conversion of squid pen by Pseudomonas aeruginosa K187 fermentation for the production of N-acetyl chitooligosaccharides and biofertilizers

Pseudomonas aeruginosa K187, a protease- and chitinase-producing bacterium, exhibited protease and chitinase activity after three and five days of incubation, respectively. The protease and chitinase were both produced by using 1% squid pen powder (SPP) (w/v) as sole carbon and nitrogen source. After fermentation, the deproteinization rate of the recovered squid pen gradually increased up to 68% on the fourth day. After five days of fermentation, the production of GlcNAc, (GlcNAc) 2, (GlcNAc) 3, (GlcNAc) 4 and (GlcNAc) 5 were 1.18 mg/mL, 0.76 mg/mL, 1.02 mg/mL, 0.93 mg/mL and 0.90 mg/mL, respectively. The culture supernatant of K187 also exhibited activity of enhancing vegetable growth. For Brassica chinensis Linn treated with the fifth day culture supernatant, the total weight and total length increased up to 529% and 148%, respectively, compared to the control group. With this method, the production of protease, chitinase, N-acetyl chitooligosaccharides and biofertilizers may be useful for biological applications.

Screening of protease-producing Serratia marcescens FS-3 and its application to deproteinization of crab shell waste for chitin extraction

Serratia marcescens FS-3, isolated from a soil sample in the southwestern area of Korea, exhibited a strong protease activity of 60.7 U/ml after 3 days of incubation. The protein removal from natural crab shell wastes with 10% S. marcescens FS-3 inoculum was 84% after 7 days of fermentation. At the same time, 47% demineralization occurred. When the shell waste was treated with 1% Delvolase ® as a reference, deproteinization rate was 90%. In combination of 10% S. marcescens FS-3 culture supernatant and 1% Delvolase ®, deproteinization rate of the shell waste was 85%, while the rate was 81% in 10% FS-3 culture supernatant only. These results suggest that bio-deproteinization of the crab shell wastes using S. marcescens FS-3 could be applicable to the chitin production process.

Enzymatic preparation of chitosan from the waste Aspergillus niger mycelium of citric acid production plant

A new route had been devised for obtain chitosan with stable properties and good quality suitable for medical, cosmetic and other purposes. Waste Aspergillus niger mycelia from a citric acid production plant were used as a source of chitosan. The extraction of chitosan was operated with lysozyme, snailase, neutral protease and novel chitin deacetylase from Scopulariopsis brevicaulis at the optimum condition of every enzyme. The optimum dosage of neutral protease and chitin deacetylase were 0.17 g (5100 units) per 100 g fresh mycelia and 1200 units per 100 g fresh mycelia, respectively. The deproteinization rate was 59.9%. The recovery rate of glucosamine was 50%. Weight-averaged molecular weight, degree of deacetylation of chitosan and the content of glucosamine were 267.97 kDa, 73.6 and 84.4%, respectively. Compared with chemical extraction methods, the weight-average molecular weight was three times higher whilst other parameters were very similar. The results of FT-IR, X-ray and elemental analysis proved that the structure of chitosan of enzymatic extraction was very similar to those of shrimp chitosan.

Response Surface Optimization and Kinetics of Isolating Chitin from Pink Shrimp (Solenocera melantho) Shell Waste

Response surface methodology has been applied to the isolation of chitin from pink shrimp shell powder. The optimal deproteinization condition occurs at 75 °C, 2.5 N NaOH. A minimal solution to solid ratio of 5 mL/g is required to maintain fluidity during deproteinization. Deproteinization exhibits two-stage first-order reaction kinetics. The maximum deproteinization rate constant approaches 0.1 min-1 when the protein content is decreased from 16% to slightly above 7%. After the first 30 min, the deproteinization rate constant could decrease up to 2 orders of magnitude. The optimal demineralization condition is around 1.7 N HCl, with an acid solution to solid ratio of 9 mL/g at ambient temperature. Demineralization could be described as a pseudo-first-order reaction. The demineralization rate constant ranges from 0.00020 to 0.017 min-1. Keywords: Chitin; deproteinization; demineralization; optimization; kinetics