Highly efficient deproteinization with an ammonifying bacteria Lysinibacillus fusiformis isolated from brewery spent diatomite

To explore a new method for bio-regeneration of high-protein brewery spent diatomite, an ammonifying bacteria (BSD1) was screened out from it and identified as Lysinibacillus fusiformis. The protein degradation characteristics of BSD1 was studied with rice protein as the sole nitrogen source. Maximum protein degradation activity was obtained when BSD1 was inoculated with an inoculum of 5% into a medium with glucose as carbon source and initial pH value of 7.0 and incubated at 30°C for 48 h. In this optimal condition, protein concentration decreased from 156.8 mg/L to 19.2 mg/L, and protein degradation efficiency of BSD1 reached 88%. Free amino acid analysis showed that the content of Phe, Tyr, Pro, Ala, Lys, Thr and His increased in protein degradation process. After degradation, NH₄⁺N concentration producing in medium supernatant reached 232.2 mg/L. These results indicated the strain BSD1 could transform proteins into free amino acids and eventually convert them to ammonium or ammonia. Furthermore, strain BSD1 could also be used for deproteinization of brewery spent diatomite and 51% of proteins in spent diatomite were degraded. After biological deproteinization the specific surface area and total pore volume of diatomite improved obviously. These results illustrated that the application of strain BSD1 for bio-regeneration of high-protein brewery spent diatomite was efficient and feasible.

Simultaneous production of amylases and proteases by Bacillus subtilis in brewery wastes

The simultaneous production of amylase (AA) and protease (PA) activity by Bacillus subtilis UO-01 in brewery wastes was studied by combining the response surface methodology with the kinetic study of the process. The optimum conditions (T=36.0°C and pH=6.8) for high biomass production (0.92g/L) were similar to the conditions (T=36.8°C and pH=6.6) for high AA synthesis (9.26EU/mL). However, the maximum PA level (9.77EU/mL) was obtained at pH 7.1 and 37.8°C. Under these conditions, a considerably high reduction (between 69.9 and 77.8%) of the initial chemical oxygen demand of the waste was achieved. In verification experiments under the optimized conditions for production of each enzyme, the AA and PA obtained after 15h of incubation were, respectively, 9.35 and 9.87EU/mL. By using the Luedeking and Piret model, both enzymes were classified as growth-associated metabolites. Protease production delay seemed to be related to the consumption of non-protein and protein nitrogen. These results indicate that the brewery waste could be successfully used for a high scale production of amylases and proteases at a low cost.

Production, Purification, and Biochemical Characterization of Thermostable Metallo-Protease from Novel Bacillus alkalitelluris TWI3 Isolated from Tannery Waste

Protease enzymes in tannery industries have enormous applications. Seeking a potential candidate for efficient protease production has emerged in recent years. In our study, we sought to isolate proteolytic bacteria from tannery waste dumping site in Tamilnadu, India. Novel proteolytic Bacillus alkalitelluris TWI3 was isolated and tested for protease production. Maximum protease production was achieved using lactose and skim milk as a carbon and nitrogen source, respectively, and optimum growth temperature was found to be 40 °C at pH 8. Protease enzyme was purified using ammonium sulfate precipitation method and anion exchange chromatography. Diethylaminoethanol (DEAE) column chromatography and Sephadex G-100 chromatography yielded an overall 4.92-fold and 7.19-fold purification, respectively. The 42.6-kDa TWI3 protease was characterized as alkaline metallo-protease and stable up to 60 °C and pH 10. Ca(2+), Mn(2+), and Mg(2+) ions activated the protease, while Hg(2+), Cu(2+), Zn(2+), and Fe(2+) greatly inhibited it. Ethylenediaminetetraacetic acid (EDTA) inhibited TWI3 protease and was activated by Ca(2+), which confirmed that TWI3 protease is a metallo-protease. Moreover, this protease is capable of dehairing goat skin and also removed several cloth stains, which makes it more suitable for various biotechnological applications.