Bioflocculation is a physicochemical technique often employed to efficiently remove colloidal water pollutants. Consequently, in this study, a bioflocculant was produced, characterised and applied to remove pollutants in mine wastewater. The maximum flocculation activity of 92% was recorded at 30 °C, pH 9.0 when maltose and urea were used as energy sources and 72 h of fermentation at the inoculum size of 1% (v/v). K+ proved to be a favourable cation. The bioflocculant yield of 4 g/L was obtained. Scanning electron microscopy illustrated a hexagonal-like structure of the bioflocculant. It is composed of carbohydrates and proteins in mass proportion of 88.6 and 9.5%, respectively. The Fourier transform infrared spectrum revealed the presence of hydroxyl, amide and amino functional groups. More than 73% of the bioflocculant was obtained after exposure to 600 °C using the thermogravimetric analyser. Human embryonic kidney 293 (HEK 293) cells exhibited 95% viability after being treated with 200 µg/µL of the bioflocculant. The flocculation mechanisms were proposed to be as a result of a double layer compression by K+, chemical reactions and bridging mechanism. The removal efficiencies of 59, 72, and 75% on biological oxygen demand, chemical oxygen demand and sulphur, were obtained respectively. Thus, the bioflocculant have potential use in wastewater treatment.

Background Endophytes, especially those that are found from ethnopharmacologically noteworthy medicinal plants have attracted attention due to their diverse bioactive metabolites of pharmacological importance. Methods This study aimed at isolating endophytic bacterium from the leaves of Anredera cordifolia CIX1 for its bioactive metabolites. The endophytic isolates were identified by 16S rRNA sequence and investigated for antibiotic sensitivity using different antibiotics. The secondary metabolites were evaluated for antibacterial activity against four bacterial strains. The 2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2′-azinobis (3- ethylbenzothiazoline-6-sulfonic acid) (ABTS) methods were used to assess their scavenging activities. The chemical components were analysed by gas chromatography-mass spectrometry (GC-MS). Results Out of 13 isolates, Isolate 1 was identified as Pseudomonas aeruginosa CP043328.1. It was resistant to clindamycin, ertapenem, penicillin G, amoxicillin, cephalothin and kanamycin but sensitive to imipenem, meropenem, and gentamycin. Its extract demonstrated antibacterial activity with minimum inhibitory concentration value of 0.098 against Bacillus cereus (ATCC 10102) and Staphylococcus aureus (ATCC 25925) and 0.391 mg/ml against Escherichia coli (ATCC 25922) and Proteus mirabilis (ATCC 25933). The extract revealed DPPH and ABTS scavenging activities with half maximal inhibitory concentration value of 0.650 mg/ml and 0.15 mg/ml, respectively. The GC-MS revealed a total of 15 compounds with diisooctyl phthalate (50.51%) and [1, 2, 4] oxadiazole, 5-benzyl-3 (10.44%) as major components. Conclusions P. aeruginosa CP043328.1 produced secondary metabolites with antibacterial and antioxidant activities.

No abstract

A variety of flocculants have been used to aggregate colloidal substances. However, recently, owing to the adverse effects and high costs of conventional flocculants, natural flocculants such as microbial flocculants are gaining attention. The aim of the study was to produce and characterize a bioflocculant from Pichia kudriavzevii MH545928.1 and apply it in wastewater treatment. A mixture of butanol and chloroform (5:2 v/v) was used to extract the bioflocculant. Phenol–sulphuric acid, Bradford and Carbazole assays were utilized for the identification of carbohydrates, proteins and uronic acid, respectively. Scanning electron microscopy (SEM) and elemental detector were employed to determine the surface morphology and elemental compositions. The removal efficiencies were 73%, 49% and 47% for BOD, COD and P, respectively. The bioflocculant (2.836 g/L) obtained showed the presence of carbohydrates (69%), protein (11%) and uronic acid (16%). The bioflocculant displayed a cumulus-like structure and the elemental composition of C (16.92%), N (1.03%), O (43:76%), Na (0.18%), Mg (0.40%), Al (0.80%), P (14.44%), S (1.48%), Cl (0.31%), K (0.34%) and Ca (20.35). It showed the removal efficiencies of 43% (COD), 64% (BOD), 73% (P) and 50% (N) in coal mine wastewater. This bioflocculant is potentially viable to be used in wastewater treatment.

No abstract

Biolocculants are gaining attention in research due to their environmental friendliness and innocuousness to human in comparison to the conventional flocculants. The present study aimed to investigate the ability of fungi from Kombucha tea SCOBY to produce effective bioflocculant in bulk. A 16S rRNA gene sequence analysis was utilized to identify the isolate. The medium composition (carbon and nitrogen sources) and culture conditions (inoculum size, temperature, shaking speed, pH, and time) were optimized using one-factor-at-a-time method. The functional groups, morphology, and crystallinity of the bioflocculant were evaluated using Fourier transform infrared (FT-IR), scan electron microscope (SEM) and X-ray diffractometry (XRD). The fungus was found to be Pichia kudriavzevii MH545928.1. It produced a bioflocculant with flocculating activity of 99.1% under optimum conditions; 1% (v/v) inoculum size, glucose and peptone as nutrient sources, 35 °C, pH 7 and the shaking speed of 140 rpm for 60 h. A cumulus-like structure was revealed by SEM; FT-IR displayed the presence of hydroxyl, carboxyl, amine, and thiocynates. The XRD analysis demonstrated the bioflocculant to have big particles with diffraction peaks at 10° and 40° indicating its crystallinity. Based on the obtained results, P. kudriavzevii MH545928.1 has potential industrial applicability as a bioflocculant producer.

Encephalartos ferox is cycad belonging to the Zamiaceae family. It is endemic in northern Kwazulu-Natal, South Africa. 12 The plant parts, especially the leaves are used as prophylaxis in the treatment of oestrogen-dependent tumour and diabetes. 13 However, there are limited studies reporting on the medicinal properties of its fruit. Our previous study investigated the chemical composition of the E. ferox methanolic fruit extract. The gas chromatography mass spectrophotometry chromatogram profile revealed a total of eight volatile compounds namely cis-Vaccenic acid (1), 9-Octadecenoic acid, 1,2,3-propanetriyl ester (2), 4H-Pyran-4-one, 2,3-dihydro-3,5-dihydroxy (3), 9-Hexadecenoic acid (4) and Pentadecanoic acid (5). Other compounds were 10-Octadecenoic acid, methyl ester (6), Hexadecanoic acid, 2-hydroxy-1-(hydroxym) (7) and 11, 14-Eicosadienoic acid, methyl ester (8). These compounds have been recognised to possess ABSTRACT Background: Plant based products are recognised as sources of drugs for treatment of diseases. Objective: The study aimed at predicting the physicochemical, pharmacokinetics, drug-likeness and toxicity of the compounds identified from the methanolic Encephalartos ferox fruit extract. Methods: The physicochemical, pharmacokinetics properties and bioactive scores of the compounds were predicted using SwissADME and Molinspiration computational tools. Drug-likeness of the compounds was evaluated based on the Lipinski rule of five (Ro5). In silico mutagenicity, carcinogenicity and inhibition of human ether-ago go related (hERG) gene were also investigated using PreADMET web tool. Results: The physicochemical properties showed the compounds, except 9-Octadecenoic acid, 1, 2, 3-propanetriyl ester to adhere to Ro5. The evaluation of their inhibitory effects profile in several cytochrome P450 isoforms indicate that all the compounds are not the inhibitors of CYP2C19 and CYP3A4 whereas some inhibited CYP1A2, CYP2C9 and CYP2D6. The drug-likeness evaluation employed Ro5 as a filter and all compounds complied with it except for 9-Octadecenoic acid, 1, 2, 3-propanetriyl ester. About 50% of the tested compound were found to be safe as they did not exhibit antimutagenic and carcinogenic effects. Moreover, the risk of inhibition of hERG gene revealed to be low to medium risk depending on the compound. Conclusion: The calculated physicochemical and pharmacokinetic properties suggest that most of the compounds are safe and have promising oral bioavailability.

The constant increase in drug resistance, occurrence of incurable diseases and high medical costs, have necessitated bio-prospecting of fungi as alternative sources of therapeutic compounds. This study aimed at assessing the antibacterial effect and mode of action of secondary metabolites from fungal endophyte associated with Aloe ferox Mill. Endophytic fungus was isolated from the gel of A. ferox and identified by internal transcribed spacer (ITS) rRNA gene sequence analysis. The targets of antibacterial activity were assessed based on minimum inhibitory concentration (MIC) and the effect of the extract on respiratory chain dehydrogenase (RCD) and membrane integrity. Fourier transform-infrared spectrophotometer (FTIR) was employed to ascertain functional groups. The fungus with the most promising antibiotic-production was identified as Aspergillus welwitschiae MK450668.1. Its extract exhibited antibacterial activity with the MIC values of 0.5 and 1 mg/mL against Staphylococcus aureus (ATCC 25925) and Escherichia coli (ATCC 25922). It demonstrated the inhibitory effect on the RCD activity and destruction of membrane integrity on the test bacteria. FTIR spectrum revealed hydroxyl, amine and alkene groups. A. welwitschiae MK450668.1 serves as a potential source of effective compounds to combat the challenge of drug resistance.