Purification of Aspergillus sp. S1-13 chitinases and their role in saccharification of chitin in mash of solid-state culture with shellfish waste.
In a suspension of solid-state culture of Aspergillus sp. S1-13 containing a lactic acid-treated crab shell as the substrate, the saccharification of chitin in the shell proceeded to form N-acetylglucosamine (GlcNAc): the culture was the source of chitin and chitinases. The analysis of chitinases in the water-extract of the solid-state culture indicated occurrence of an exochitinase (Exo, MW 73 kDa) and two endochitinases. The amounts of the endochitinases suggested that one of them (Endo-1, MW 45 kDa) might be the main species in the chitin-saccharification. The amount of GlcNAc released from the LA-treated crab shell by the combined action of isolated Exo and Endo-1 was very small, predicting participation in the saccharification of other enzyme species, which might be hardly extracted with water from the solid-state culture. The re-extraction of the solid-state culture using 2 M KCl, which was extracted with water beforehand, demonstrated another endochitinase (Endo-2, MW 51 kDa). Endo-2 isolated from the salt-extract can adsorb to chitin, and can hydrolyze the chitin in the adsorbed state. The roles of these chitinases in the chitin-saccharification based on their properties and combined action were discussed.
Rattanakit
Nopakarn
N
Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
Yano
Shigekazu
S
Plikomol
Abhinya
A
Wakayama
Mamoru
M
Tachiki
Takashi
T
D000117:Acetylglucosamine / Q000378:metabolism; D000818:Animals; D001230:Aspergillus / Q000201:enzymology* / Q000378:metabolism; D001673:Biodegradation, Environmental; D002686:Chitin / Q000378:metabolism*; D002688:Chitinases / Q000302:isolation & purification* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008970:Molecular Weight; D012037:Refuse Disposal; D012758:Shellfish; D013696:Temperature; D014866:Waste Products
D014866:Waste Products; D002686:Chitin; D002688:Chitinases; D000117:Acetylglucosamine