Keratin is a fibrous protein mainly found in higher vertebrates such as mammals, birds, and reptiles. It is also a major constituent of human epithelial tissues. Major keratinaceous wastes include skin, hair, wool, feather, horns, hooves, and nails. Large amounts of such wastes are generated from meat industry, poultry houses, and wool industry etc. Though keratinous wastes contain about 90% protein, keratin is usually recalcitrant to normal proteases. Such wastes have been traditionally digested using physico-chemical methods. But such techniques are energy-intensive and technologically demanding. Also, such approaches lead to degradation of certain amino acids such as lysine. In nature, keratinaceous wastes don’t accumulate indicating that keratinolytic microorganisms exist in nature. Keratinase producing strains are distributed among bacteria, fungi, and actinobacteria etc. Hence, potent keratinolytic microbes and their enzymes may be used for valorization of keratinous wastes. Efficient degradation of such wastes may generate value-added products such as feed additives, agricultural biofertilizers, and cosmetics. This chapter will give a comprehensive overview of types of keratinaceous wastes, kinds of keratinolytic microbes and keratinases, and valorization of such wastes using keratinase producing strains and/or keratinases.

The long regimen of drug therapy, the emergence of drug-resistance (DR), and infections with non-tuberculous mycobacteria (NTMs) are alarming challenges in controlling tuberculosis (TB), a disease caused by Mycobacterium tuberculosis (M.tb), necessitating the pursuit of new, broad-spectrum anti-mycobacterials. With more than two-thirds of the clinically useful antibiotics originating from the bacterial phylum Actinomycetota, and their enormous diversity in India, we explored atypical environments for new bacterial strains with potential anti-M.tb activity. In this study, we the examined the secondary metabolites of soil and endophytic bacterial isolates from the wetland niches of Manipur, India, and determined their anti-mycobacterial properties using viability assays. The ethyl acetate culture filtrate extracts of one of the isolates, named Streptomyces sp. SbAr007, showed broad-spectrum anti-mycobacterial activity against laboratory M.tb strains H37Ra and H37Rv, a clinical drug-resistant M.tb and non-tuberculous mycobacteria (NTM). The isolate was characterized for its phenotype and genetic identity, which indicated its closeness to Streptomyces samsunensis, Streptomyces malaysiensis, and Streptomyces solisilvae. Further, macrophage infection assays showed that the extracts could effectively control the intracellular mycobacterial growth but had negligible cytotoxicity to PBMCs from healthy donors. LC-MS identified an unusual combination of antibiotics in these culture filtrate extracts, which can be further explored for specific active molecules or as a formulation against DR-TB.

Bonnaya ruellioides (Colsm.) Spreng is an ethnomedicinal plant widely found in Manipur, a northeastern state of India and it belongs to the Linderniaceae family. The study aimed to evaluate the phytochemical content, trace metals, antioxidant and antimicrobial activity of this ethnomedicinal plant in various extracts including chloroform, petroleum ether, ethyl acetate, methanol, and water extracts. Phytochemical analysis was done using standard protocols, trace metals content by using Atomic Absorption Spectrophotometer (AAS), antioxidant by DPPH, Reducing Power and ABTS assay. Antimicrobial activity of the plant was also determined by Zone of Inhibition (ZOI) assay. Phytochemicals such as phenol, saponin, flavonoid, alkaloid, and terpenoid were detected in the water extract, whereas tannin, glycoside, flavonoid, steroid, alkaloid, and terpenoid were found in the plant extracts of petroleum ether, chloroform, and ethyl acetate. Trace elements detection using AAS revealed the presence of Fe (0.298 ± 0.011 mg/g), Zn (0.083 ± 0.003 mg/g), Cu (0.024 ± 0.002 mg/g) and Mn (0.014 ± 0.002 mg/g) in the plant. Further, evaluation of antioxidant activity using DPPH scavenging assay in chloroform and methanol extracts recorded 411.59 ±2.62 IC50 (μg/mL ± SD) and 80.96 ± 0.68 IC50 (μg/mL ± SD) respectively. Reducing power activity of the chloroform and methanol extracts showed 249.27 ± 1.48 μM FeSO4/mg sample and 44.55 ± 0.47 μM FeSO4/mg sample, respectively, and for ABTS assay, 281.82 ± 2.19 TEAC/g dw and 168.65 ± 2.06 TEAC/g dw are recorded respectively. The antimicrobial study of the chloroform and petroleum ether extracts showed negative results for all the selected pathogens of bacterial and fungal strains. At the same time, the methanol extract showed positive for bacterial strains including Micrococcus luteus (17.50 ±0.54) mm and Escherichia coli (15.0 ± 2.0) mm, while negative for all the fungal strains. The results of the study demonstrated for the first time that B. ruellioides plant has notable phytochemical, essential trace metals, promising antioxidant and antimicrobial capacity. Thus, the findings of our study will contribute a scientific insight into the therapeutic applications of this ethnomedicinal plant in folklore medicines and enable the prediction of further applications in drug development.