ABSTRACT
BACKGROUND: With the growing concern for the environment, there are trends that bio-utilization of keratinous waste by keratinases could ease the heavy burden of keratinous waste from the poultry processing and leather industry. Especially surfactant-stable keratinases are beneficial for the detergent industry. Therefore, the production of keratinase by Bacillus cereus YQ15 was improved; the characterization and use of keratinase in detergent were also studied. RESULTS: A novel alkaline keratinase-producing bacterium YQ15 was isolated from feather keratin-rich soil and was identified as Bacillus cereus. Based on the improvement of medium components and culture conditions, the maximum keratinase activity (925 U/mL) was obtained after 36 h of cultivation under conditions of 35 °C and 160 rpm. Moreover, it was observed that the optimal reacting temperature and pH of the keratinase are 60 °C and 10.0, respectively; the activity was severely inhibited by PMSF and EDTA. On the contrary, the keratinase showed remarkable stability in the existence of the various surfactants, including SDS, Tween 20, Tween 60, Tween 80, and Triton X-100. Especially, 5% of Tween 20 and Tween 60 increased the activity by 100% and 60%, respectively. Furtherly, the keratinase revealed high efficiency in removing blood stains. CONCLUSION: The excellent compatibility with commercial detergents and the high washing efficiency of removing blood stains suggested its suitability for potential application as a bio-detergent additive.
Subject(s)
Bacillus cereus , Detergents , Animals , Bacillus cereus/metabolism , Detergents/chemistry , Enzyme Stability , Feathers/metabolism , Hydrogen-Ion Concentration , Keratins/metabolism , Peptide Hydrolases/metabolism , Polysorbates , Surface-Active Agents , TemperatureABSTRACT
BACKGROUND: The prevalence of asthma and allergic diseases has risen in recent decades. The etiology of asthma and allergic diseases has not been entirely elucidated. OBJECTIVE: In this study, we investigated the possibility that programmed vaccination in China may have a potential role in asthma and allergic diseases. METHODS: In this animal model, newborn BALB/c mice were randomly divided into three groups: vaccine plus ovalbumin (OVA), OVA, and control. The mice of vaccine plus OVA only group were inoculated with vaccines by following the National Vaccines Inoculation Program in China. Mice of vaccine plus OVA and OVA only groups were sensitized and challenged with OVA. Airway hyperresponsiveness was assessed by lung function and serum interleukin (IL) 4 and interferon (IFN) γ were measured. RESULTS: The results of lung function showed that mice of the vaccine plus OVA group exhibited an increase in enhanced pause (Penh) compared with that in the OVA group at methacholine concentrations of 6.25 and 12.5 mg/mL (p < 0.05). Serum IL-4 in the vaccine plus OVA group was higher than that in the OVA group (p < 0.01). The serum IFN-γ level in the OVA group was lower than that in the control group (p < 0.01), and also lower than that in the vaccine plus OVA group (p < 0.05). The ratio of IFN-γ to IL-4 both in the OVA and vaccine plus OVA group was lower than that in the control group (p < 0.01). CONCLUSIONS: Results of our study indicated that programmed vaccination in China may have a potential role in the prevalence of asthma and allergic diseases by inducing T-helper 2 cytokine expression and may be responsible for the increasing prevalence of asthma and allergic diseases in China.
