Microbial keratinases: industrial enzymes with waste management potential

Verma, Amit; Singh, Hukum; Anwar, Shahbaz; Chattopadhyay, Anirudha; Tiwari, Kapil K.; Kaur, Surinder; Dhilon, Gurpreet Singh

doi:10.1080/07388551.2016.1185388

Cited by 123 publications

(88 citation statements)

References 135 publications

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“…About 2 million tons of feathers are generated annually as a by‐product of poultry industry globally . Due to poor management, poultry waste especially feathers have become one of the major pollutants due to their recalcitrant nature .…”

Section: Introductionmentioning

confidence: 99%

“…They can act as habitats for sustaining many pathogenic microorganisms such as Vibrio and Salmonella . It also emits various pollutants viz., ammonia, nitrous oxide, hydrogen sulphide, thereby, adversely affecting human health, and environment . However, feathers are considered a good source of peptides, essential amino acids, and minerals like N, phosphorus, potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) .…”

Section: Introductionmentioning

confidence: 99%

“…health, and environment [1,4]. However, feathers are considered a good source of peptides, essential amino acids, and minerals like N, phosphorus, potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) [5,6].…”

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confidence: 99%

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Feather degradation by keratinolytic bacteria and biofertilizing potential for sustainable agricultural production

et al. 2018

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Feathers account for 5–7% of the total weight of chicken have become one of the major pollutants due to their recalcitrant nature. Feather which is constituted of 90% keratin can be a good source of peptides, amino acids, and minerals for use as organic fertilizer. Traditional feather degradation methods consume large amount of energy and reduces the overall quality of the proteins. However, degradation of keratin by keratinolytic bacteria may represent as an alternative for the development of cheap, cost effective, eco‐friendly, and easily available nitrogen (N) and minerals rich source as potential organic fertilizers. Keratinase enzymes from bacteria are serine‐type proteases showing optimal activity at pH 6 to 9 and 30 to 50 °C. Mechanism of degradation includes, sulfitolysis, proteolysis, followed by deamination. Keratinolytic bacteria showing antagonism against important plant pathogens may act as biocontrol agent. Feather hydrolyzate can also be employed as nitrogenous fertilizers for plant growth. Tryptophan release from the feather degradation can act as precursor for plant phytohormone, indole‐3‐acetic acid (IAA). Solubilization of inorganic phosphate (P) by keratinolytic bacteria may further elevate the growth of plant. Application of hydrolyzate increases the water holding capacity, N, carbon (C) and mineral content of the soil. It elevates protein, amino acids, and chlorophyll content of plant. Feather hydrolyzate enhances seed germination and growth of plant. Soil application further increases the population of beneficial bacteria. The use of keratinolytic bacteria having antagonistic and plant growth promoting activities, and feather hydrolyzate can emerge as sustainable and alternative tools to promote and improve organic farming, agro‐ecosystem, environment, human health, and soil biological activities.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Feather degradation by keratinolytic bacteria and biofertilizing potential for sustainable agricultural production

et al. 2018

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“…Microbial consortia have shown numerous advantages for the processing of recalcitrant molecules and materials which are hard to degrade or convert (9), and may even represent environmental and threats (26). Microorganisms represent a colossal, yet still a poorly tapped resource for applied microbiology and biotechnology.…”

Section: Resultsmentioning

confidence: 99%

“…Keratinous materials are classified as one of the waste materials categories according to European parliament regulations (25). They could cause an environmental imbalance and potential pollution to soil or water because of their recalcitrant form in municipal waste (26). Hence, seeking the effective approach to keratinous waste management will contribute to eliminate their environmental risks.…”

Section: Introductionmentioning

confidence: 99%

Construction of simplified microbial consortia to degrade recalcitrant materials based on enrichment and dilution-to-extinction cultures

Kang

Jacquiod

Herschend

et al. 2019

Preprint

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The capacity of microbes degrading recalcitrant materials has been extensively explored from environmental remediation to industrial applications. Although significant achievements were obtained with single strains, focus is now going toward the use of microbial consortia because of advantages in terms of functional stability and efficiency. While consortia assembly attempts were made from several known single strains, another approach consists in obtaining consortia from complex environmental microbial communities in search for novel microbial species, genes and functions. However, assembling efficient microbial consortia from complex environmental communities is far from trivial due to large diversity and biotic interactions at play. Here we propose a strategy containing enrichment and dilution-to-extinction cultures to construct simplified microbial consortia (SMC) for keratinous waste management, from complex environmental communities. Gradual dilutions were performed from a keratinolytic microbial consortium, and dilution 10−9 was selected to construct a SMC library. Further compositional analysis and keratinolytic activity assays demonstrated that microbial consortia were successfully simplified, without impacting their biodegradation capabilities. These SMC possess promising potential for efficient keratinous valorization. More importantly, this reasoning and methodology could be transferred to other topics involving screening for simplified communities for biodegradation, thus considerably broadening its application scope.ImportanceMicrobial consortia have got more and more attention and extensive applications due to their potential advantages. However, a high diversity of microbes is likely to hide uncontrollable risks in practice specific to novel strains and complicated interaction networks. Exploring a convenient and efficient way to construct simplified microbial consortia is able to broaden the applied scope of microbes. This study presents the approach based on enrichment and dilution-to-extinction cultures, which gain abundance microbial consortia including some without losing efficiency from the enriched functional microbial community. The microbial interactions at the strain level were evaluated by using compositional identification and correlation analysis, which contribute to revealing the roles of microbes in the degradation process of recalcitrant materials. Our findings provide a systematic scheme to achieve optimizing microbial consortia for biodegradation from an environmental sample, could be readily applied to a range of recalcitrant materials management from environmental remediation to industrial applications.

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