Improved Stability and Hydrolysates of Hyperthermophilic GH57 Type II Pullulanase from the Deep-Sea Archaeon Thermococcus siculi HJ21 by Truncation

• Published in: Catalysts 2023-03, Vol.13 (3), p.453
• Main Authors: Wu, Xudong, Dou, Baojie, Wang, Boyan, Liu, Mingwang, Shao, Ruxue, Lu, Jing, Lyu, Mingsheng, Wang, Shujun
• Format: Article
• Language: English
• Subjects: Amino acids; Amylases; Building materials industry; Carbohydrates; Catalysts; Chemical reactions; Deep sea environments; Efficiency; Enzyme activity; Enzymes; Glucose; Heat resistance; Hydrolysates; Industrial production; Proteins; Pullulanase; Signal transduction; Stability analysis; Structural models; Thermal stability
• ISSN: 2073-4344; 2073-4344
• DOI: 10.3390/catal13030453

Pullulanase (EC 3.2.1.41) belongs to the amylase family and is often used alone or in combination with other amylases in the industrial production of starch-based products. This enzyme is often required in industrial production because of its better stability. We here truncated the pullulanase gene from the deep-sea hydrothermal anaerobic archaeon Thermococcus siculi HJ21 and obtained Pul-HJΔ782, which is a member of the α-amylase family GH57. The results revealed that the optimum temperature for Pul-HJΔ782 was 100 °C, and its thermostability at 100 °C improved after truncation. Less than 15% of its enzyme activity was lost after 1 h of incubation at 100 °C, and 57% activity remained after 5 h of treatment. Truncation significantly improved the overall pH tolerance range of Pul-HJΔ782, and its stability in the pH range 4–8 was over 80% relative activity from an average of 60%. The sequence and structural model of Pul-HJΔ782 was analyzed, and its instability index was reduced significantly. Furthermore, the hydrolysates of the truncated and wild-type pullulanase were analyzed, and the enzymatic digestion efficiency of the truncated Pul-HJΔ782 was higher.