Study of cellulases from a newly isolated thermophilic and cellulolytic Brevibacillus sp. strain JXL

Abstract

A potentially novel aerobic, thermophilic, and cellulolytic bacterium designated as Brevibacillus sp. strain JXL was isolated from swine waste. Strain JXL can utilize a broad range of carbohydrates including: cellulose, carboxymethylcellulose (CMC), xylan, cellobiose, glucose, and xylose. In two different media supplemented with crystalline cellulose and CMC at 57 degrees C under aeration, strain JXL produced a basal level of cellulases as FPU of 0.02 IU/ml in the crude culture supernatant. When glucose or cellobiose was used besides cellulose, cellulase activities were enhanced ten times during the first 24 h, but with no significant difference between these two simple sugars. After that time, however, culture with glucose demonstrated higher cellulase activities compared with that from cellobiose. Similar trend and effect on cellulase activities were also obtained when glucose or cellobiose served as a single substrate. The optimal doses of cellobiose and glucose for cellulase induction were 0.5 and 1%. These inducing effects were further confirmed by scanning electron microscopy (SEM) images, which indicated the presence of extracellular protuberant structures. These cellulosome-resembling structures were most abundant in culture with glucose, followed by cellobiose and without sugar addition. With respect to cellulase activity assay, crude cellulases had an optimal temperature of 50 degrees C and a broad optimal pH range of 6-8. These cellulases also had high thermotolerance as evidenced by retaining more than 50% activity at 100 degrees C after 1 h. In summary, this is the first study to show that the genus Brevibacillus may have strains that can degrade cellulose.

Enhanced Cellulase Production by a Novel Thermophilic Bacillus licheniformis 2D55: Characterization and Application in Lignocellulosic Saccharification

“…Different sets of enzymes are induced by different substrates (Liang et al 2010). Similar results was observed for a thermophilic Brevibacillus JXL as different optimum temperatures were observed in crude cellulase induced by glucose and by cellobiose (Liang et al 2009(Liang et al , 2010a. Recently, cellulase from a thermophilic B. vallismortis RG-07 recorded optimum activity at 65 °C, and 105 °C (Gaur and Tiwari 2015).…”

The Dual Carboxymethyl Cellulase and Gelatinase Activities of a Newly Isolated Protein from Brevibacillus agri ST15c10 Confer Reciprocal Regulations in Substrate Utilization

“…A novel thermophilic and cellulolytic bacterium, Brevibacillus sp. strain JXL, shows similar physicochemical conditions for optimum enzymatic activity [Liang et al, 2009[Liang et al, , 2010. The CMCase activity in our investigation is moderately stimulated by the reducing agent (2-mercaptoethanol) [Mandels and Reese, 1965], suggesting a possible redox regulation of the enzyme.…”

culture conditions for production of cellulase by Aspergillus tubingensis KY615746 using rice straw waste

“…Growth medium pH strongly influences many enzymatic reactions by affecting the transport of a number of chemical products and enzymes across the cell membrane (Liang et al 2009 andKapoor et al 2008). The results presented in Fig.…”