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Recent Advancements in Microbial Enzymes and Their Application in Bioremediation of Xenobiotic Compounds
Published in Pankaj Bhatt, Industrial Applications of Microbial Enzymes, 2023
Saurabh Gangola, Pankaj Bhatt, Samiksha Joshi, Saurabh Kumar, Narendra Singh Bhandari, Samarth Terwari, Om Prakash, Amit Kumar Mittal
Animal molting and shedding, horns, nails, and poultry feces are resistant to breakdown due to the presence of insoluble keratin protein. Along with their unpleasant odor, they are responsible for environmental degradation. Keratinase is a protease enzyme that degrades keratin proteins and can be used in the bioremediation of poultry wastes. Keratinase enzyme developed from Stenotrophomonas maltophilia KB13 and Bacillus sp. FPF-1 has revealed a considerable breakdown activity of chicken feathers (Bhange et al., 2016), indicating its capacity to degrade recalcitrant keratinous waste biomass from the agriculture sector (Nnolim et al., 2020). Disulfide reductase and serine protease from Stenotrophomonas sp. worked together to successfully degrade keratin, resulting in a 50-fold increase in keratinolytic activity over protease alone. The breaking of disulfide bonds in the keratin protein is catalyzed by the disulfide reductase (Yamamura et al., 2002). Keratinase enzymes synthesized by Pseudomonas sp. and Bacillus sp. hydrolyzes keratinous wastes obtained from different origins (Mazotto et al., 2011). Keratinase is employed in leather industries for the most crucial dehairing step to replace the chemical treatment of Na2S and CaO (Akhter et al., 2020).
Recent Trends in Application of Feather Keratin Hydrolysate Produced through Bioconversion of Poultry Feather Waste
Published in Jitendra Kumar Saini, Surender Singh, Lata Nain, Sustainable Microbial Technologies for Valorization of Agro-Industrial Wastes, 2023
Pintubala Kshetri, Subhra Saikat Roy, Thangjam Surchandra Singh, Pangambam Langamba, K. Tamreihao, Susheel Kumar Sharma, Ayekpam Bimolini Devi
Conventionally, feathers are degraded by various chemical or physical methods. These methods involve the use of harmful chemicals and large energy expenses which compromise the environment (Park and Son 2009). Nevertheless, in the year 1990, Shih and his coworkers have shown that feathers could be degraded by microbial action (Williams et al. 1990). They have isolated and characterized a nonpathogenic feather-degrading bacterium, Bacillus licheniformis PWD1. Since then, researchers have focused on isolation, identification, and characterization of feather-degrading microbes and their mechanism of action. From their collective research findings, it was shown that the mechanism of keratin degradation is a complex process involving a synergistic action, sulfitolysis/reduction (to cleave the disulfide bond) and proteolysis (to cleave the peptide bond). The enzyme responsible for the degradation of keratin is known as keratinase (Sharma and Devi 2018). So far, many keratinolytic microbes belonging to various genera and keratinase enzymes with different catalytic activity have been reported. Microbial or enzymatic hydrolysis of feather keratin is an eco-friendly approach for the valorization of feather waste into value-added products (Haq et al. 2020). Microbial or enzymatic hydrolyzed feather has a wide range of applicability in many industrial sectors, which include agricultural, leather, pharmaceutical, cosmeceutical, etc. Further exploration of microbial or enzymatic hydrolyzed feathers for applications in other important sectors is continuing among many researchers. Keeping this in view, the chapter focuses on the importance of valorization of feather waste, the role of keratinolytic bacteria and their keratinase enzymes in bioconversion of feather waste, as well as potential applications of feather hydrolysate (FH).
Biodiscovery of Marine Microbial Enzymes in Indonesia
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Ekowati Chasanah, Pujo Yuwono, Dewi Seswita Zilda, Siswa Setyahadi
One of the serine proteases is the keratinase enzyme (E.C. 3.4.99.11), which is able to hydrolyze the disulfide hydrogen bonds in the keratin proteins. Keratinolytic proteases are also generally from metalloprotease regardless of the microbial source Nnolim, Udenigwe, Okoh, & Nwodo, 2020). Microbial keratinases are continuously gaining an important role due to their effective bioconversion of hard keratin–rich wastes, that is, feathers from the poultry industry, as cost-effective substrates, and they are utilized to produce high-value products such as amino acids and bioactive peptides. In the feed industry, keratinolytic peptidase enzymes, that is, a protease that hydrolyzes keratin in fibrous animal protein such as feather, horns, hair, and nails as natural waste, could be used as a supplement in the animal feed and leather industries, in detergent formulation, in cosmetics and in organic fertilizer production (Kalaikumari et al., 2018; Nnolim et al., 2020). The biodiscovery of the keratinase enzyme from marine microbes has been reported (Lintang, Suhartono, Hwang, & Pyun, 2007; Rahayu, Bata, & Hadi, 2014). Thermostable keratinolytic protease was secreted by the L-23 isolate from a coastal hot spring in North Sulawesi, Indonesia. The enzyme was maximally produced when the L-23 isolate was cultivated using a selective medium containing 1% chicken feather powder at 70°C and a pH 7, and the keratinolytic protease worked best at 65°C and pH 7. The pure enzyme had an estimated molecular weight of 47 and 64 kDa. Keratinase has also been reported to be produced intracellularly and extracellularly by Bacillus sp. and Bacillus licheniformis MB-2 isolated from Indonesia. The keratinase was used to produce chicken feather meal. A substitution feeding trial showed that keratin meal from chicken feather can be used to substitute as much as 53% without significant difference (P > 0.05) on growth, feed consumption and conversion of the growing layer (Rahayu et al., 2014). The thermostable keratinolytic enzyme was also produced by Brevibacillus thermoruber LII, which is optimally active at temperatures between 45–55°C and a pH of 6–7. The Brevibacillus thermoruber LII bacteria were able to degrade untreated chicken feathers after 24 h incubation in a liquid medium (Zilda et al., 2012). In addition to the feed industry, the application of keratinase was also reported in cosmetics products as a bioactive compound in the preparation of topical products used as hair removals Nnolim et al., 2020), as well as for dehairing sheepskin. In a concentration of 5% or 86.75 U/g keratinase (w/dwt. skin), the enzyme was able to remove the hair of sheepskin very efficiently similar to that of the chemical methods used traditionally (Kalaikumari et al., 2018).
Chryseobacterium aquifrigidense keratinase liberated essential and nonessential amino acids from chicken feather degradation
Published in Environmental Technology, 2023
Amahle Bokveld, Nonso E. Nnolim, Tennison O. Digban, Anthony I. Okoh, Uchechukwu U. Nwodo
Keratinase production is generally effectuated in the presence of keratinous substrate by bacterial producers [13]. Hence, keratinase biosynthesis is highly regulated, and such regulation determines keratinase titre in culture media [34]. The concentration of keratinous biomass could trigger commensurable keratinase secretion for the bioconversion of keratin into bioavailable products. These products serve as nutrients to sustain the bacteria’s carbon and nitrogen requirements [35]. However, as observed from the present study, a higher concentration of keratinous biomass might lead to the accumulation of copious degradation products in the media, which may signal for downregulation of the keratinase biosynthetic pathway. Other reports have linked the fermentation medium’s viscosity and poor aeration as the significant factors that prompt reduction in extracellular keratinase production when a higher concentration of keratinous substrates is added to fermentation media [25,36]. The utilization of cost-effective chicken feathers as a sole source of carbon and nitrogen by C. aquifrigidense FANN2 indicates its significance in sustainable development.
Study on the use of bovine blood protein hydrolysate as a peptone in microbial culture media
Published in Preparative Biochemistry & Biotechnology, 2023
Nasim Rezaee, Pedram Hasanvand, Tayebe Bagheri Lotfabad, Amir Heydarinasab, Mahvash Khodabandeh, Soheila Yaghmaei
However, depending on the source of the protein, different methods are used for hydrolysis. For example, keratin, a protein found in feathers, bristles, horns, beaks, and wool is structurally hydrolyzed by acid, alkalis, or keratinase. Enzymatic or microbial hydrolysis, on the other hand, is frequently used for the hydrolysis of animal proteins like meat, intestine, casein, and whey, as well as plant proteins such as rice, wheat, pea, soy, and cottonseed.[17]