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.

Lignocellulose consists of cellulose, hemicellulose, and lignin and is a sustainable feedstock for a biorefinery to generate marketable biomaterials like biofuels and platform chemicals. Enormous tons of lignocellulose are obtained from agricultural waste, but a few tons are utilized due to a lack of awareness of the biotechnological importance of lignocellulose. Underutilizing lignocellulose could also be linked to the incomplete use of cellulose and hemicellulose in biotransformation into new products. Utilizing lignocellulose in producing value-added products alleviates agricultural waste disposal management challenges. It also reduces the emission of toxic substances into the environment, which promotes a sustainable development goal and contributes to circular economy development and economic growth. This review broadly focused on lignocellulose in the production of high-value products. The aspects that were discussed included: (i) sources of lignocellulosic biomass; (ii) conversion of lignocellulosic biomass into value-added products; and (iii) various bio-based products obtained from lignocellulose. Additionally, several challenges in upcycling lignocellulose and alleviation strategies were discussed. This review also suggested prospects using lignocellulose to replace polystyrene packaging with lignin-based packaging products, the production of crafts and interior decorations using lignin, nanolignin in producing environmental biosensors and biomimetic sensors, and processing cellulose and hemicellulose with the addition of nutritional supplements to meet dietary requirements in animal feeding.

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.

This study was designed to evaluate the potential of bioflocculant producing strains isolated from wastewater sludge. According to the Plackett–Burman design, the response surface revealed glucose, magnesium sulfate, and ammonium sulfate as critical media components of the nutritional source, whereas the central composite design affirmed an optimum concentration of the critical nutritional source as 16.0 g/l (glucose), 3.5 g/l magnesium sulfate heptahydrate (MgSO₄.7H₂O), and 1.6 g/l ammonium sulfate ( (NH₄)₂SO₄), yielding an optimal flocculation activity of 96.8%. Fourier Transformer Infrared Spectroscopy (FTIR) analysis confirmed the presence of hydroxyl, carboxyl and methoxyl in the structure of the bioflocculant. Additionally, chemical analysis affirmed the presence of mainly a polysaccharide in the main backbone of the purified bioflocculant with no detection of protein. Energy Dispersive X-ray analysis affirmed the presence of chlorine, phosphorous, oxygen and chlorine as representatives of elemental composition. Thermogravimetric (TGA) analysis revealed over 60% weight was retained at a temperature range of 700 °C. The purified bioflocculant remarkably removed chemical oxygen demand, biological oxygen demand and turbidity in brewery wastewater. This study suggested that the bioflocculant might be an alternate candidate for wastewater treatment.

Helianthus annus (sunflower) is a globally important oilseed crop whose survival is threatened by various pathogenic diseases. Agrochemical products are used to eradicate these diseases; however, due to their unfriendly environmental consequences, characterizing microorganisms for exploration as biocontrol agents are considered better alternatives against the use of synthetic chemicals. The study assessed the oil contents of 20 sunflower seed cultivars using FAMEs-chromatography and characterized the endophytic fungi and bacteria microbiome using Illumina sequencing of fungi ITS 1 and bacteria 16S (V3–V4) regions of the rRNA operon. The oil contents ranged between 41–52.8%, and 23 fatty acid components (in varied amounts) were found in all the cultivars, with linoleic (53%) and oleic (28%) acids as the most abundant. Ascomycota (fungi) and Proteobacteria (bacteria) dominated the cultivars at the phyla level, while Alternaria and Bacillus at the genus level in varying abundance. AGSUN 5102 and AGSUN 5101 (AGSUN 5270 for bacteria) had the highest fungi diversity structure, which may have been contributed by the high relative abundance of linoleic acid in the fatty acid components. Dominant fungi genera such as Alternaria, Aspergillus, Aureobasidium, Alternariaste, Cladosporium, Penicillium, and bacteria including Bacillus, Staphylococcus, and Lactobacillus are established, providing insight into the fungi and bacteria community structures from the seeds of South Africa sunflower.

Stalactites (CaCO3 and salt) from water seeps are frequently encountered in ceilings of mine tunnels whenever they intersect water-bearing faults or fractures. To determine whether stalactites could be mineralized traps for indigenous fracture water microorganisms, we analyzed stalactites collected from three different mines ranging in depth from 1.3 to 3.1 km. During sampling in Beatrix gold mine (1.4 km beneath the surface), central South Africa, CaCO3 stalactites growing on the mine tunnel ceiling were collected and discovered, in two cases, to contain a living obligate brackish water/marine nematode species, Monhystrella parvella. After sterilization of the outer surface, mineral layers were physically removed from the outside to the interior, the DNA extracted. Based upon 16S and 18S rRNA gene sequencing, Archaea, Bacteria and Eukarya in different combinations were detected for each layer. . Using CT scan and electron microscopy the inner structure of CaCO3 and salt stalactites were analyzed. CaCO3 stalactites show a complex pattern of lamellae carrying bacterially precipitated mineral structures. Nematoda were clearly identified between these layers confirming that bacteria and nematodes live inside the stalactites and not only in the central straw. Salt stalactites exhibit a more uniform internal structure. Surprisingly, several Bacteria showing highest sequence identities to marine Bacteria were identified. This, together with the observation that the nematode M. parvella recovered from Beatrix gold mine stalactite can only survive in a salty environment makes the origin of the deep subsurface colonization enigmatic. The possibility of a Permian origin is discussed. Our results indicate stalactites are suitable for biodiversity recovery and act as natural traps for microorganisms in the fissure water long after the water that formed the stalactite stopped flowing.