One of the major challenges faced in commercial production of lignocellulosic bioethanol is the inhibitory compounds generated during the thermo-chemical pre-treatment step of biomass. These inhibitory compounds are toxic to fermenting micro-organisms. The ethanol yield and productivity obtained during fermentation of lignocellulosic hydrolysates is decreased due to the presence of inhibiting compounds, such as weak acids, furans and phenolic compounds formed or released during thermo-chemical pre-treatment step such as acid and steam explosion. This review describes the application and/or effect of biological detoxification (removal of inhibitors before fermentation) or use of bioreduction capability of fermenting yeasts on the fermentability of the hydrolysates. Inhibition of yeast fermentation by the inhibitor compounds in the lignocellulosic hydrolysates can be reduced by treatment with enzymes such as the lignolytic enzymes, for example, laccase and micro-organisms such as Trichoderma reesei, Coniochaeta ligniaria NRRL30616, Trametes versicolor, Pseudomonas putida Fu1, Candida guilliermondii, and Ureibacillus thermosphaericus. Microbial and enzymatic detoxifications of lignocellulosic hydrolysate are mild and more specific in their action. The efficiency of enzymatic process is quite comparable to other physical and chemical methods. Adaptation of the fermentation yeasts to the lignocellulosic hydrolysate prior to fermentation is suggested as an alternative approach to detoxification. Increases in fermentation rate and ethanol yield by adapted micro-organisms to acid pre-treated lignocellulosic hydrolysates have been reported in some studies. Another approach to alleviate the inhibition problem is to use genetic engineering to introduce increased tolerance by Saccharomyces cerevisiae, for example, by overexpressing genes encoding enzymes for resistance against specific inhibitors and altering co-factor balance. Cloning of the laccase gene followed by heterologous expression in yeasts was shown to provide higher enzyme yields and permit production of laccases with desired properties for detoxification of lignocellulose hydrolysates. A combination of more inhibitor-tolerant yeast strains with efficient feed strategies such as fed-batch will likely improve lignocellulose-to-ethanol process robustness.

Phthalate esters (PEs) are by far the most produced and extensively used synthetic organic chemicals with notable applications in many industrial products such as vinyl upholstery, adhesives, food containers, packaging materials, printing inks, adhesives, cosmetics, paints, pharmaceuticals munitions, and insecticides among other. PEs have long been recognised as ubiquitous organic pollutants of prime environmental concern, with urbanisation amongst the main cause and source of these compounds. Due to their notoriety, these compounds are known to pose devastating effects to living organisms including humans. The presence of PEs and their metabolites in the aquatic ecosystems is of concern primarily due to their endocrine disrupting and carcinogenicity properties. Several research studies have reported prevalence, exposure pathways, toxicity, and impacts of PEs in aquatic ecosystems and humans. Their principal routes of exposure could be direct or indirect, of which the direct route include contact, eating, and drinking contaminated foods, and the indirect route constitute aerosols, leaching and other forms of environmental contamination. PEs find way into water systems through means such as effluent discharges, urban and agricultural land runoff, leaching from waste dumps and other diffuse sources. High-end instrumentation and improved methodologies on the other hand have resulted in increased ability to measure trace levels (μg/L) of PEs and their metabolites in different matrices and ecological compartments of water or aquatic ecosystems such as lakes, oceans, rivers, sediments, wetlands and drinking water samples. In light of the above, this article provides an informed and focused information on the prevalence of phthalate esters in aquatic systems and related effects on living organisms and humans. Furthermore, techniques that have enabled the extraction and analysis of these PEs in aquatic samples are also explained. Future research outlooks and needs are also highlighted in this manuscript. This information will be used to better understand their temporal and spatial distributions in the aquatic systems and aid in devising prudent means to curtail their ecological footprints.

Microalgae are photosynthetic microorganisms that can produce lipids, proteins and carbohydrates in large amounts and within short periods of time and these can be processed into both biofuels and other useful commercial products. Due to this reason microalgae are considered as a potential source of renewable energy; and one of the most important decisions in obtaining oil from microalgae is the choice of species. In this study, the potential of Chlorophyceae species isolated from freshwater and soda lakes in Hungary and Romania (Central Europe) were characterized and evaluated by determining their biomass accumulation, lipid productivity, fatty acid profiles, and biodiesel properties besides protein and carbohydrate productivity. Out of nine strains tested, three accumulated more than 40% dry weight of protein, four accumulated more than 30% dry weight of carbohydrate and the strain Chlorella vulgaris LC8 accumulated high lipid content (42.1% ± 2.6%) with a favorable C16-C18 fatty acid profile (77.4%) as well as suitable biodiesel properties of high cetane number (57.3), low viscosity (4.7 mm²/s), lower iodine number (75.18 g I₂/100 g), relative cloud point (8.8 °C) and negative cold filter plugging point (−6.5 °C). Hence the new strain, Chlorella vulgaris LC8 has potential as a feedstock for the production of excellent quality biodiesel.