A novel chitinase (LpChiA) was purified to homogeneity from a culture of Laceyella putida JAM FM3001. LpChiA hydrolyzed colloidal chitin optimally at a pH of 4 in an acetate buffer and temperature of 75 ºC. The enzyme was remarkably stable to incubation at 70 ºC up to 1 h at pH 5.2, and its activity half-life was 3 days. The molecular mass of the enzyme was around 38 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and around 75 kDa by gel filtration, suggesting it is a homodimer. The enzyme activity was enhanced about 60% when pre-incubated with anionic, cationic, and nonionic surfactants. The gene for LpChiA was cloned by PCR and sequenced. The nucleotide sequence of the gene consisted of 1,683 bp encoding 560 amino acids. The N-terminal and internal amino acid sequences of the purified LpChiA from L. putida suggested that the mature enzyme was composed of 384 amino acids after cleaving its 176 N-terminal amino acids and dimerized to express its activity. The deduced amino acid sequence of the mature enzyme showed the highest similarity to chitinase of Laceyella sacchari with 79% identity.

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In this paper, design of a model-following controller with stabilized digital inverse system in a closed loop is proposed. In this paper, the proposed inverse system is placed in front of the plant. Our model-following control system was developed using the above structure. However, when the relative degree of the transfer function for a continuous-time plant is greater than 3, the discrete-time system is often in the non-minimum phase. In addition, unstable zeros appear when the chosen sampling period is too short. To solve these problems, an auxiliary output is used in the design. We designed a closed-loop system to consider the robustness of the proposed controller. In addition, a parallel feedforward compensator is added in parallel with the plant  Index Terms-stabilized inverse system, multi-sampling rate, model-following control, parallel feedforward compensator R. Murakami received the B.

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