| Summary: | 碩士 === 國立臺灣海洋大學 === 食品科學系 === 101 === It has been confirmed that Chitinbacter tainanensis could hydrolysed chitin to perform N-acetyl-glucosamine (NAG) production. In this study, different type of chitin were prepared and were used as substrate for C. tainanensis to study the influence of molecular chain and spatial structure of chitin on degradation. α-Chitin and β-chitin were tempered to 75%, 50% and 35% moisture content and equilibrated at 25℃ then being puffed in a puffing gun. The effect of puffing to chitin were analyzed by FT-IR, XRD and so on. The results showed that the degree of deacetylation were raised with increasing moisture content both in α-chitin and β-chitin. The color values of chitin were significantly changed with the decreased of puffed moisture content. The bulk density were also significantly decreased with the decreased of puffed moisture content. The particle size of unpuffed chitin was 60-80 mesh. The particle size of puffed chitin was major in 10-60 mesh, minor below 80 mesh. The proportion of 10-60 mesh fraction was raised with increasing the moisture content. However, the proportion of below 80 mesh fraction was decreased with increasing the moisture content. The particle size of puffed chitin with lower moisture content were mostly distributed below 80 mesh and the puffed β-chitin had a significantly changed. The hole on surface of chitin were became bigger and increase with the decreased of puffed moisture content were observed by scanning electron microscopy. The result of XRD showed that the crystal structure of α-chitin were significantly destroyed than β-chitin after being puffed. The crystal structure of puffed chitin was strongly destroyed with a lower moisture content.
Moreover, this study suggested that either puffed α-chitin or β-chitin with different moisture content was more easily utilized by C. tainanensis than the unpuffed chitin. Meanwhile, there was a significantly increased of conversion rate of NAG was produced by cultivated with puffed α-chitin with 75% moisture content after 72 hours. Although -chitin were not easily utilized, it can be improved by treatment of puffing. Besides, the activity of enzyme and biomass were increased by cultivated with puffed chitin. Meanwhile, it can be observed that a high production of NAG from puffed chitin with 35% moisture content by the isolated enzyme.
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