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.

In vitro assessment of the bioactivities of sericin protein extracted from a bacterial silk-like biopolymer.

Sericin is one of the main components of silk proteins, which has numerous biomedical applications because of its antioxidant, anticancer and antimicrobial properties. We recently isolated and characterized a novel silk-like protein named BNES. It is of non-animal origin and is like a bacterial polymeric silk. Sericin is a very popular protein compound that is effective in treating cancerous tumors. The process of extracting it from natural silk produced by silkworms or spiders is both complex and expensive. From the published scientific literature, it has been shown that sericin has not been previously extracted from a bacterial source. In the present study, sericin was extracted from bacteria capable of producing a biopolymer named BNES whose chemical composition is like that of natural silk and its bio-therapeutic effects were evaluated for the first time. The antioxidant activity of BNES measured by DPPH and ABTS assays showed IC50 values of 0.38 and 0.41 mg mL-1, respectively. BNES displayed satisfactory cytotoxic effect against four cancer cell lines, including Huh-7, Caco-2, MCF-7 and A549 cells, with IC50 values in the ranges of ca. 0.62 ± 0.17, 0.72 ± 0.27, 0.76 ± 0.36 and 0.83 ± 0.31 mg mL-1, respectively, after 24 h of treatment and 0.51 ± 0.22, 0.49 ± 0.19, 0.41 ± 0.25 and 0.55 ± 0.38, respectively, after 48 h of treatment, without affecting normal cells (WI38 cells). The antitumor activity of BNES was established to be an apoptosis-dependent mechanism determined via cellular morphology alterations, cell cycle arrest in the sub-G1 phase and nuclear staining with highly fluorescent fragments. The antimicrobial effects of BNES were examined with yeast and Gram-negative and Gram-positive bacteria. The results confirmed its antimicrobial activity against all tested organisms at concentrations of up to 1.33 mg mL-1. The competitive advantage of the bacterial sericin BNES over sericin extracted from spider or silkworm sources is that it can be produced in very large quantities through large-scale bio-fermenters, which reduces the expected cost of production, in addition to having sustainable bacterial production source.

Disinfection of water and wastewater by biosynthesized magnetite and zerovalent iron nanoparticles via NAP-NAR enzymes of Proteus mirabilis 10B.

Disinfection of water and wastewater strongly contributes to solving the problem of water shortage in arid/semi-arid areas; cheap and ecofriendly approaches have to be used to meet water quality standards. In the present study, a green synthesis of iron nanoparticles (INPs) under aerobic and anaerobic conditions via nitrate reductases (NAP/NAR) enzymes produced by Proteus mirabilis strain 10B were employed for this target. The biosynthesized INPs were characterized; UV-Vis spectroscopy revealed surface plasmon resonance at 410 (aerobic) and 265 nm (anaerobic). XRD indicated crystalline magnetite ((MNPs) aerobically synthesized) and zerovalent INPs (ZVINPs anaerobically synthesized). EDX demonstrated strong iron signal with atomic percentages 73.3% (MNPs) and 61.7% (ZVINPs). TEM micrographs illustrated tiny, spherical, periplasmic MNPs (1.44-1.92 nm) and cytoplasmic ZVINPs with 11.7-60.8 nm. Zeta potential recorded - 31.8 mV (ZVINPs) and - 66.4 mV (MNPs) affirming colloidal stability. Moreover, the disinfection power of INPs was evaluated for standards organisms and real water (fresh, sea and salt mine) and wastewater (municipal, agricultural and industrial) samples. The results reported that INPs displayed higher antagonistic effect than iron precursor, 700 and 850 µg/mL of MNPs and ZVINPs, respectively, was sufficient to show a drastic algicidal effect on algal growth. Both types of INPs demonstrated obvious dose-dependent antibiofilm efficiency. Due to their smaller size, MNPs were more efficient than ZVINPs at the suppression of microbial growth in all examined water samples. Overall, MNPs showed superior antagonistic activity, which promotes their exploitation in enhancing water/wastewater quality.

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.