Feather Degradation and Keratinase Production by &lt;i&gt;Stenotrophomonas maltophilia&lt;/i&gt; DHHJ

Wu, Xiao Qian; Chen, Li; Cao, Zhang Jun; Zhou, Mingyang

doi:10.4028/www.scientific.net/amr.550-553.1400

Cited by 1 publication

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“…Moreover, neutral to weakly alkaline pH was more suitable for bacteria including B. tropicus Gxun-17 to produce keratinase [ 34 – 36 ]. Some reports have shown that the keratinase activity of B. licheniformis ALW1 reached 72.2 U/mL, that of B. zhangzhou reached 49.96 U/mL and that of S. maltophilia DHHJ reached 10.0 U/mL by optimising fermentation conditions and fermentation medium [ 8 , 10 , 11 ]. After optimisation, the keratinase activity of B. tropicus Gxun-17 in this study reached 112.57 U/mL, which was 3.18-fold higher than the activity of basic medium.…”

Section: Discussionmentioning

confidence: 99%

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Isolation and identification of a feather degrading Bacillus tropicus strain Gxun-17 from marine environment and its enzyme characteristics

et al. 2022

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Background Feathers are the most abundant agricultural waste produced by poultry farms. The accumulation of a large number of feathers not only seriously pollutes the environment but also causes the waste of protein resources. The degradation of feather waste by keratinase-producing strains is currently a promising method. Therefore, screening high-producing keratinase strains from marine environment and studying the fermentation conditions, enzymatic properties and feather degradation mechanism are crucial for efficient degradation of feathers. Results A novel efficient feather-degrading bacteria, Gxun-17, isolated from the soil sample of a marine duck farm of Beibu Gulf in Guangxi, China, was identified as Bacillus tropicus. The optimum fermentation conditions were obtained by single factor and orthogonal tests as follows: feather concentration of 15 g/L, maltose concentration of 10.0 g/L, MgSO4 concentration of 0.1 g/L, initial pH of 7.0 and temperature of 32.5 °C. The strain completely degraded the feathers within 48 h, and the highest keratinase activity was 112.57 U/mL, which was 3.18-fold that obtained with the basic medium (35.37 U/mL). Detecting the keratinase activity and the content of sulphur-containing compounds in the fermentation products showed that the degradation of feathers by the strain might be a synergistic effect of the enzyme and sulphite. The keratinase showed optimal enzyme activity at pH 7.0 and temperature of 60 °C. The keratinase had the best performance on the casein substrate. When casein was used as the substrate, the Km and Vmax values were 15.24 mg/mL and 0.01 mg/(mL·min), respectively. Mg2+, Ca2+, K+, Co2+, Al3+, phenylmethylsulphonyl fluoride and isopropanol inhibited keratinase activity, which indicated that it was a serine keratinase. Conversely, the keratinase activity strongly increased with the addition of Mn2+ and β-mercaptoethanol. Conclusions A novel feather-degrading B. tropicus Gxun-17 was obtained from marine environment. The strain adapted the extreme conditions such as low temperature, high salt and high pressure. Thus, the keratinase had high activity, wide range of temperature and pH, salt tolerance and other characteristics, which had potential application value.

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Section: Discussionmentioning

confidence: 99%

“…LM19 after the optimisation of conditions [ 9 ]. After optimisation, keratinase activity of Stenotrophomonas maltophilia DHHJ reached 10.0 U/mL [ 10 ].…”

Section: Introductionmentioning

confidence: 99%