Back to nature: henna extracts from nanotech to environmental biotechnology - a review.

The Lythraceae family includes henna (Lawsonia inermis), which thrives in subtropical and tropical climates. One of its many and long-standing uses is in cosmetics as a pigment to color hair and nails. Additionally, it serves as a disinfectant against microbiological infections and has traditional applications in the textile industry, specifically for coloring wool and nylon. The dried leaves of henna contain a significant amount of lawsone, an active substance bestowing them with staining abilities. Environmental biotechnology, a subfield of biotechnology, engages in the production of biomass or renewable energy sources and the elimination of pollutants, utilizing either entire organisms or their by-products. Recent research indicates that henna, owing to its sustainability, abundant production, simplicity of preparation, low cost, and reputation for being safe and ecologically benign, is exceptionally well-suited to participate in the realm of environmental biotechnology. This review navigates through the most recent studies exploring the use of henna and its extracts for related purposes. These encompass a spectrum of applications, including but not limited to nanobiotechnology, fabric dyeing, corrosion resistance, colored solar cells, carbon dots, and new renewable energy exemplified by biofuel and biohydrogen. Furthermore, henna extracts have been deployed to function as antimicrobials and ward off dangerous insects.

Biosynthesis of polyhydroxyalkanotes in wild type yeasts.

Biosynthesis of biodegradable polymers polyhydroxyalkanotes (PHAs) have been studied extensively in wild type and genetically modified prokaryotic cells, however the content and structure of PHAs in wild type yeasts is not well documented. The purpose of this study was to screen yeast isolates collected from different ecosystems for their ability to accumulate PHAs. Identification of the isolates and characterization of PHAs produced by the positive isolates were investigated. One positive isolate (strain Y4) was identified by both API20C system and 18S rDNA sequencing. The data revealed that isolate Y4 belongs to the yeast genus Rhodotorula and exhibits 18S rDNA similarity value >99% to the species Rhodotorula minuta. Quantification of PHAs yield of strain Y4 in glucose, oleic acid and tween 60 containing medium for over a growth period of 96 h gave 2% of PHAs in biomass. The nature of produced PHAs was analyzed by infrared spectroscopy and nuclear magnetic resonance (1H and 13C NMR) and found to contain polyhydroxybutyrate and polyhydroxyvalerate (PHBV).

Isolation and characterization of extracellular bioflocculants produced by bacteria isolated from Qatari ecosystems.

Compared with conventional synthetic flocculants, bioflocculants has special advantages such as safety, strong effect, biodegradable and harmlessness to humans and the environment, so they may potentially be applied in drinking and wastewater treatment, downstream processing, and fermentation processes. To utilize bioflocculants widely in industrial fields, it is desirable to find various microorganisms with high bioflocculant-producing ability and improve the flocculating efficiency of the bioflocculant. In the present study, screening of new flocculant-producing microorganisms was carried out using samples collected from different Qatari ecosystems. The flocculating activity of the novel bioflocculants produced by isolated microorganisms was investigated. A total of 5 g/l Kaolin suspension was used to measure the flocculating activity. Isolated bioflocculant-producing bacteria were identified by 16S rDNA analysis, using PCR with universal primers. Comparative analysis of the 16S rDNA sequence (approximately 550 bp) in the GenBank database revealed that these bacteria are related to the genus Bacillus. FT-IR spectrometry analysis of the extracted bioflocculants indicated the presence of carboxyl, hydroxyl and amino groups preferred for the flocculation process. Influences of pH and bioflocculant dosage on the flocculation were also examined. The maximum flocculating rates were observed at pH 7, 7 and 3 of the bioflocculants derived from strains QUST2, QUST6 and QUST9, respectively. However, 20.0 mg/l was the dose that gave the highest flocculating rate with all examined bioflocculants. The elemental analysis of examined bioflocculants revealed the mass proportion of C, H, N and S. Carbon and nitrogen contents of examined bioflocculants were in the range of 42-48% and 11-12%, respectively.