Chitin purification from shrimp wastes by microbial deproteination and decalcification.
Chitin was purified from Penaeus monodon and Crangon crangon shells using a two-stage fermentation process with anaerobic deproteination followed by decalcification through homofermentative lactic acid fermentation. Deproteinating enrichment cultures from sewage sludge and ground meat (GM) were used with a proteolytic activity of 59 and 61 mg N l(-1) h(-1) with dried and 26 and 35 mg N l(-1) h(-1) with wet P. monodon shells. With 100 g wet cells of proteolytic bacteria per liter, protein removal was obtained in 42 h. An anaerobic spore-forming bacterium HP1 was isolated from enrichment GM. Its proteolytic activity was 76 U ml(-1) compared to 44 U ml(-1) of the consortium. Glucose was fermented with Lactobacillus casei MRS1 to lactic acid. At a pH of 3.6, calcium carbonate of the shells was solubilised. After deproteination and decalcification of P. monodon or C. crangon shells, the protein content was 5.8% or 6.7%, and the calcium content was 0.3% or 0.4%, respectively. The viscosity of the chitin from P. monodon and C. crangon was 45 and 135 mPa s, respectively, whereas purchased crab shell chitin (practical grade) had a viscosity of 21 mPa s, indicating a higher quality of biologically purified chitin.
Xu
Y
Y
Institut für Ingenieurbiologie und Biotechnologie des Abwassers, Universität Karlsruhe, Am Fasanengarten, Karlsruhe, Germany.
Gallert
C
C
Winter
J
J
D000693:Anaerobiosis; D000818:Animals; D001419:Bacteria / Q000378:metabolism*; D001711:Biotransformation; D002118:Calcium / Q000378:metabolism*; D002686:Chitin / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D033501:Crangonidae / Q000737:chemistry / Q000378:metabolism*; D005285:Fermentation; D007218:Industrial Microbiology; D007220:Industrial Waste / Q000032:analysis*; D033561:Penaeidae / Q000737:chemistry / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*
D007220:Industrial Waste; D011506:Proteins; D002686:Chitin; D002118:Calcium