Bacillus sp. CSB39, isolated from popular traditional Korean food (Kimchi), produced a low molecular weight, thermostable mannanase (MnCSB39); 571.14 U/mL using locust bean gum galactomannan as a major substrate. It was purified to homogeneity using a simple and effective two-step purification strategy, Sepharose CL-6B and DEAE Sepharose Fast Flow, which resulted in 25.47% yield and 19.32-fold purity. The surfactant-, NaCl-, urea-, and protease-tolerant monomeric protein had a mass of similar to 30 kDa as analyzed by SDS-PAGE and galactomannan zymography. MnCSB39 was found to have optimal activity at pH 7.5 and temperature of 70 degrees C. The enzyme showed square 55% activity at 5.0-15% (w/v)NaCl, and square 93% of the initial activity after incubation at 37 degrees C for 60 min. Trypsin and proteinase K had no effect on MnCBS39. The enzyme showed square 80% activity in up to 3 M urea. The N-terminal amino acid sequence, ALKGDGX, did not show identity with reported mannanases, which suggests the novelty of our enzyme. Activation energy for galactomannan hydrolysis was 26.85 kjmol(-1) with a K-cat of 142.58 x 10(4) s(-1). MnCSB39 had K-m and V-max values of 0.082 mg/mL and 1099 +/- 1.0 Umg(-1), respectively. Thermodynamic parameters such as Delta H, Delta G, Delta S, Q(10), Delta G(E-S), and Delta G(E-T) supported the spontaneous formation of products and the high hydrolytic efficiency and feasibility of the enzymatic reaction, which strengthen its novelty. MnCSB39 activity was affected by metal ions, modulators, chelators, and detergents. Mannobiose was the principal end-product of hydrolysis. Bacillus subtilis CSB39 produced a maximum of 1524.44U mannanase from solid state fermentation of 1 g wheat bran. MnCSB39 was simple to purify, was active at a wide pH and temperature range, multi-stress tolerant and catalyzes a thermodynamically possible reaction, characteristics that suggests its suitability for application as an industrial biocatalyst. (C) 2016 Elsevier Inc. All rights reserved.