Lactic acid (LA) has broad applications in the food, chemical, pharmaceutical, and cosmetics industries. LA production demand rises due to the increasing demand for polylactic acid since LA is a precursor for polylactic acid production. Fermentative LA production using renewable resources, such as lignocellulosic materials, reduces greenhouse gas emissions and offers a cheaper alternative feedstock than refined sugars. Suitable pretreatment methods must be selected to minimize LA cost production, as the successful hydrolysis of lignocellulose results in sugar-rich feedstocks for fermentation. This review broadly focused on fermentative LA production from lignocellulose. Aspects discussed include (i). low-cost materials for fermentative LA production, (ii). pretreatment methods, (iii). enzymatic hydrolysis of cellulose and hemicellulose, (iv). lactic acid-producing microorganisms, including fungi, bacteria, genetically modified microorganisms, and their fermentative pathways, and (v). fermentation modes and methods. Industrial fermentative lactic acid production and purification, difficulties in using lignocellulose in fermentative LA production, and possible strategies to circumvent the challenges were discussed. A promising option for the industrial production and purification of LA that contains enzyme and cell recycling continuous simultaneous saccharification and fermentation coupled with membrane-based separation was proposed. This proposed system can eliminate substrate-, feedback-, and end-product inhibition, thereby increasing LA concentration, productivity, and yield.

Kombucha is a fermented tea beverage containing bioactive compounds from tea and vital compounds such as acetic acid, D-saccharic acid-1,4-lactone, and glucuronic and gluconic acids produced from the metabolic activities of bacteria and yeasts, which benefit human health. Kombucha contains a symbiotic culture of bacteria and yeast (SCOBY), which actively ferments sugar. Kombucha microbial compositions vary due to environmental conditions and the starter culture. Saccharomyces sp., Schizosaccharomyces pombe, Schizosaccharomyces sp., and Brettanomyces sp. (yeasts) and Acetobacter aceti, Komagataeibacter xylinum (formerly known as Gluconacetobacter xylinum), Gluconobacter oxydans, and Acetobacter pasteurianus (acetic acid-producing bacteria) are commonly found in kombucha. This review focused on the microbial compositions of kombucha and their functionality. Aspects discussed include: (i). developments in kombucha, (ii). microbial compositions of kombucha, (ii). microbial production of kombucha cellulose, (iv). factors influencing kombucha microbial compositions, (v). tea type and kombucha bioactive compounds, (vi). kombucha health benefits, and (v). potential risk factors of kombucha consumption. Current gaps, recommendations, and prospects were also discussed. Kombucha production using rooibos as the tea base is recommended, as rooibos is caffeine-free. Upcycling kombucha wastes, mainly SCOBY, for producing cellulose filters, improving food flavors and as a substrate in food fermentations is touched on.

The modern medical industry successfully utilizes Laser Powder Bed Fusion (LPBF) to manufacture complex custom implants. Ti6Al4V is one of the most commonly used biocompatible alloys. In surgery practice, infection at the bone–implant interface is one of the key reasons for implant failure. Therefore, advanced implants with biocompatibility and antibacterial properties are required. Modification of Ti alloy with Cu, which in small concentrations is a proven non-toxic antibacterial agent, is an attractive way to manufacture implants with embedded antibacterial functionality. The possibility of achieving alloying in situ, during manufacturing, is a unique option of the LPBF technology. It provides unique opportunities to manufacture customized implant shapes and design new alloys. Nevertheless, optimal process parameters need to be established for the in situ alloyed materials to form dense parts with required mechanical properties. This research is dedicated to an investigation of Ti6Al4V (ELI)-1 at % Cu material, manufactured by LPBF from a mixture of Ti6Al4V (ELI) and pure Cu powders. The effect of process parameters on surface roughness, chemical composition and distribution of Cu was investigated. Chemical homogeneity was discussed in relation to differences in the viscosity and density of molten Cu and Ti6Al4V. Microstructure, mechanical properties, and fracture behavior of as-built 3D samples were analyzed and discussed. Pilot antibacterial functionalization testing of Ti6Al4V (ELI) in situ alloyed with 1 at % Cu showed promising results and notable reduction in the growth of pure cultures of Escherichia coli and Staphylococcus aureus.

The excellent combination of properties has seen a steep increase in the demand for titanium (Ti)-based material as biomedical implant devices. However, some features that promote biocompatibility are found to be lacking in Ti implants. The use of polymer nanofiber (NF) coating on the surfaces of the implants has been proven to remedy these setbacks. In particular, electrospun NFs are versatile as natural extracellular matrix mimics and as facilitators in the biocompatibility function of Ti-based implants. Therefore, various properties of Ti implants coated with polymer NFs and the correlations among these properties are explored in this review. Synthetic polymers are favorable in tissue engineering applications because they are biocompatible and have low toxicity and degradation rates. Several approved synthetic polymers and polymer hybrids have been electrospun onto Ti implant surfaces to successfully improve the biomedical applicability of the implants with regard to their physical (including diameter and porosity), chemical (including corrosion resistance), mechanical (including elastic modulus, strength and ductility) and biological properties (including tissue integration, antimicrobial and cytotoxicity).

Medicinal plants are important in the South African traditional healthcare system, the growth in the consumption has led to increase in trade through muthi shops and street vendors. Medicinal plants are prone to contamination with fungi and their mycotoxins. The study investigated multiple mycotoxin contamination using Ultra High Pressure Liquid Chromatography–Tandem Mass Spectrometry (UPLC-ESI-MS/MS) for the simultaneous detection of Aflatoxin B1 (AFB1), Deoxynivalenol (DON), Fumonisins (FB₁, FB₂, FB₃), Nivalenol (NIV), Ochratoxin A (OTA) and Zearalenone (ZEN) in frequently sold medicinal plants. Medicinal plant samples (n = 34) were purchased and analyzed for the presence of eight mycotoxins. DON and NIV were not detected in all samples analyzed. Ten out of thirty-four samples tested positive for mycotoxins —AFB₁ (10.0%); OTA (10.0%); FB1 (30.0%); FB2 (50.0%); FB3 (20.0%); and ZEN (30.0%). Mean concentration levels ranged from AFB₁ (15 µg/kg), OTA (4 µg/kg), FB₁ (7–12 µg/kg), FB₂ (1–18 µg/kg), FB₃ (1–15 µg/kg) and ZEN (7–183 µg/kg). Multiple mycotoxin contamination was observed in 30% of the positive samples with fumonisins. The concentration of AFB₁ reported in this study is above the permissible limit for AFB1 (5 µg/kg). Fumonisin concentration did not exceed the limits set for raw maize grain (4000 µg/kg of FB₁ and FB₂). ZEN and OTA are not regulated in South Africa. The findings indicate the prevalence of mycotoxin contamination in frequently traded medicinal plants that poses a health risk to consumers. There is therefore a need for routine monitoring of multiple mycotoxin contamination, human exposure assessments using biomarker analysis and establishment of regulations and standards.

Biofilm formation in dental unit waterlines (DUWLs) and the consequent microbial contamination of dental chair unit (DCU) water is a significant challenge. The South African government has no explicit requirements for water quality supplied to DCUs or for disinfection protocols for DUWLs. To assess bacterial water quality and presence of biofilm-associated organisms in DUWLs of open and closed system DCUs. Standard water sampling was followed in accordance with the South African National Standard for drinking water (SANS 241:1) and used as reference for microbial water quality to measure heterotrophic plate counts (HPC) and total coliforms for possible water contamination. Pseudomonas aeruginosa and Legionella spp. are common opportunistic pathogens found in DUWL and were also assessed using selective media. HPC exceeded the national standard of <10 × 10³ CFU mL^-1 in water from both open and closed systems (1.48-6.94 × 10⁴ CFU mL^-1 and 1.71 × 10⁴ CFU mL^-1). P. aeruginosa was detected in fast handpieces, reservoir bottles, and distiller bottles of closed system DCUs. Legionella spp. (22 CFU mL^-1) were present in the output water from one fast handpiece of an open system DCU. Internal surfaces of taps, fast handpieces, distiller bottles and reservoir bottles also exhibited mean HPC counts which exceeded the national standard. Total coliforms were identified in the fast handpieces of open system DCUs (5.09 × 10³ CFU 100 mL^-1) and distiller bottles (6.23 × 10³ CFU 100 mL^-1) of closed systems. P. aeruginosa (3.64 × 10⁴ CFU mL^-1), was detected on the internal surfaces of the municipal tap supplying water to open system DCUs as well as, internal surfaces of reservoir bottles (5.9 × 10¹ CFU 100 mL^-1) and fast handpieces (1.5×10¹ CFU 100 mL^-1) of closed system DCUs. Contamination levels of DUWL water and surfaces of open and closed system DCUs were high, highlighting the need for national regulations of DUWL quality and decontamination protocols in South Africa.