Optimized biotransformation of acid-treated water melon peel hydrolyzate into ethanol

Today, global focus of research is to explore the solution of energy crisis and environmental pollution. Like other agricultural countries, bulk quantities of watermelon peels (WMP) are disposed-off in environment as waste in Pakistan and appropriate management of this waste is the need of hour to save environment from pollution. The work emphasizes the role of ethanologenic yeasts to utilize significant sugars present in WMP for low-cost bioethanol fermentation. Dilute hydrochloric acid hydrolysis of WMP was carried out on optimized conditions employing RSM (response surface methodology) following central composite design (CCD). This experimental design is based on optimization of ethanologenesis involving some key independent parameters such as WMP hydrolysate and synthetic media ratio (X1), incubation temperature (X2) and incubation temperature (X3) for maximal ethanol yield exploiting standard (Saccharomyces cerevisiae K7) as well as experimental (Metchnikowia cibodasensisY34) yeasts. The results revealed that maximal ethanol yields obtained from S. cerevisiae K7 was 0.36±0.02 g/g of reducing sugars whereas M. cibodasensisY34, yielded 0.40±0.01 g ethanol/g of reducing sugars. The yeast isolate M. cibodasensisY34 appeared as promising ethanologen and embodies prospective potential for fermentative valorization of WMP-to-bioethanol.

Metabolic phenotyping of marine heterotrophs on refactored media reveals diverse metabolic adaptations and lifestyle strategies

Microbial communities, through their metabolism, drive carbon cycling in marine environments. These complex communities are composed of many different microorganisms including heterotrophic bacteria, each with its own nutritional needs and metabolic capabilities. Yet, models of ecosystem processes typically treat heterotrophic bacteria as a "black box", which does not resolve metabolic heterogeneity nor address ecologically important processes such as the successive modification of different types of organic matter. Here we directly address the heterogeneity of metabolism by characterizing the carbon source utilization preferences of 63 heterotrophic bacteria representative of several major marine clades. By systematically growing these bacteria on 10 media containing specific subsets of carbon sources found in marine biomass, we obtained a phenotypic fingerprint that we used to explore the relationship between metabolic preferences and phylogenetic or genomic features. At the class level, these bacteria display broadly conserved patterns of preference for different carbon sources. Despite these broad taxonomic trends, growth profiles correlate poorly with phylogenetic distance or genome-wide gene content. However, metabolic preferences are strongly predicted by a handful of key enzymes that preferentially belong to a few enriched metabolic pathways, such as those involved in glyoxylate metabolism and biofilm formation. We find that enriched pathways point to enzymes directly involved in the metabolism of the corresponding carbon source and suggest potential associations between metabolic preferences and other ecologically-relevant traits. The availability of systematic phenotypes across multiple synthetic media constitutes a valuable resource for future quantitative modeling efforts and systematic studies of inter-species interactions.

Bioproduction of 2-Phenylethanol through Yeast Fermentation on Synthetic Media and on Agro-Industrial Waste and By-Products: A Review

Due to its pleasant rosy scent, the aromatic alcohol 2-phenylethanol (2-PE) has a huge market demand. Since this valuable compound is used in food, cosmetics and pharmaceuticals, consumers and safety regulations tend to prefer natural methods for its production rather than the synthetic ones. Natural 2-PE can be either produced through the extraction of essential oils from various flowers, including roses, hyacinths and jasmine, or through biotechnological routes. In fact, the rarity of natural 2-PE in flowers has led to the inability to satisfy the large market demand and to a high selling price. Hence, there is a need to develop a more efficient, economic, and environmentally friendly biotechnological approach as an alternative to the conventional industrial one. The most promising method is through microbial fermentation, particularly using yeasts. Numerous yeasts have the ability to produce 2-PE using l-Phe as precursor. Some agro-industrial waste and by-products have the particularity of a high nutritional value, making them suitable media for microbial growth, including the production of 2-PE through yeast fermentation. This review summarizes the biotechnological production of 2-PE through the fermentation of different yeasts on synthetic media and on various agro-industrial waste and by-products.

Deepfakes, misinformation and disinformation and authenticity infrastructure responses: Impacts on frontline witnessing, distant witnessing, and civic journalism

Frontline witnessing and civic journalism are impacted by the rhetoric and the reality of misinformation and disinformation. This essay highlights key insights from activities of the human rights and civic journalism network WITNESS, as they seek to prepare for new forms of media manipulation, such as deepfakes, and to ensure that an emergent “authenticity infrastructure” is in place to respond to global needs for reliable information without creating additional harms. Based on global consultations on perceived threats and prioritized solutions, their efforts are primarily targeted towards synthetic media and deepfakes, which not only facilitate audiovisual falsification (including non-consensual sexual images) but also, by being embedded in societal dynamics of surveillance and civil society suppression, they challenge real footage and so undermine the credibility of civic media and frontline witnessing (also known as “liar’s dividend”). They do this within a global context where journalists and some distant witness investigators self-identify as lacking relevant skills and capacity, and face inequity in access to detection technologies. Within this context, “authenticity infrastructure” tracks media provenance, integrity, and manipulation from camera to edit to distribution, and so comes to provide “verification subsidies” that enable distant witnesses to properly interpret eye-witness footage. This “authenticity infrastructure” and related tools are rapidly moving from niche to mainstream in the form of initiatives the Content Authenticity Initiative and Coalition for Content Authenticity and Provenance, raising key questions about who participates in the production and dissemination of audiovisual information, under what circumstances and to which effect for whom. Provenance risks being weaponized unless key concerns are integrated into infrastructure proposals and implementation. Data may be used against vulnerable witnesses, or the absence of a trail, for legitimate privacy and technological access reasons, used to undermine credibility. Regulatory and extra-legal co-option are also a fear as securitized “fake news” laws proliferate. The investigation of both phenomena, deepfakes and emergent authenticity infrastructure(s), this paper argues, is important as it highlights the risks related both to the “information disorder” of deepfakes as they challenge the credibility and safety of frontline witnesses and to responses to such “disorder,” as they risk worsening inequities in access to tools for mitigation or increasing exposure to harms from technology infrastructure.

PHA Production from Cheese Whey and “Scotta”: Comparison between a Consortium and a Pure Culture of Leuconostoc mesenteroides

It is urgent to expand the market of biodegradable alternatives to oil-derived plastics owing to (i) increasingly limited oil availability/accessibility, and (ii) the dramatic impact of traditional plastics on aquatic life, the food chain, all Earth ecosystems, and ultimately, human health. Polyhydroxyalkanoates (PHAs) are promising biodegradable polymers that can be obtained through microbial fermentation of agro-industrial byproducts, e.g., milk and cheese whey. Here, the PHA-accumulating efficiency of a mixed microbial culture (MMC, derived from activated sludges) grown on dairy byproducts (cheese and scotta whey) was measured. Bioreactor tests featuring temperature and pH control showed that both scotta and pre-treated Toma cheese whey could be used for PHA production by MMC, although scotta cheese whey supported higher PHA yield and productivity. The advantages of open MMCs include their plasticity and versatility to fast changing conditions; furthermore, no growth-medium sterilization is needed prior to fermentation. However, the use of pure cultures of efficient PHA producers may support better metabolic performances. Therefore, PHA-producing strains were isolated from an MMC, leading to the satisfactory identification of two bacterial strains, Citrobacter freundii and Leuconostoc spp., whose ability to accumulate PHAs in synthetic media was confirmed. A more detailed investigation by mass spectrometry revealed that the strain was L. mesenteroides. Although the validation of L. mesenteroides’ potential to produce PHA through fermentation of agro-industrial byproducts requires further investigations, this is the first study reporting PHA production with the Leuconostoc genus.

Omnipresence of Partitiviruses in Rice Aggregate Sheath Spot Symptom-Associated Fungal Isolates from Paddies in Thailand

Partitiviruses are one of the most prevalent double-stranded RNA viruses that have been identified mostly in filamentous fungi and plants. Partitiviruses generally infect host fungi asymptomatically but infrequently exert significant effect(s) on morphology and virulence, thus being considered a potential source of biological control agents against pathogenic fungi. In this study, we performed a screening for mycoviruses of a collection of Thai isolates of rice fungal pathogen Rhizoctonia oryzae-sativae, a causal agent of rice aggregated sheath spot disease. As a result, 36% of tested isolates carried potentially viral double-stranded RNAs with sizes ranging from 2 to 3 kbp. By conventional cDNA library construction and RNA-seq, we determined six new alphapartitiviruses that infected three isolates: tentatively named Rhizoctonia oryzae-sativae partitivirus 1 to 6 (RosPV1-6). Furthermore, RT-PCR detection of each virus revealed their omnipresent nature in different R. oryzae-sativae isolates. Although virus-curing of basidiomycetous fungi is generally difficult, our repeated attempts successfully obtained virus-free (for RosPV1, RosPV2, and uncharacterized partitiviruses), isogenic strain of R. oryzae-sativae TSS190442. The virus-cured strain showed slightly faster colony growth on the synthetic media and severe symptom development on the rice sheath compared to its virus-infected counterpart. Overall, this study shed light on the distribution of partitiviruses in R. oryzae-sativae in a paddy environment and exemplified a virus-curing protocol that may be applicable for other basidiomycetous fungi.

Pigeonpea (Cajanus cajan L.) and Cowpea (Vigna unguiculata L.) Water as Alternative Growth Medium for Escherichia coli and Staphylococcus aureus in Laboratory with Minimum Infrastructure

The availability of non-synthetic media from natural ingredients is needed to answer the needs in laboratories where the price of nutrient media is quite expensive and there are limited supplies of material ware houses. Cowpea (Vigna unguiculata L.) and pigeonpea (Cajanus cajan L.) are the local foods of people of NTT (East Nusa Tenggara) which have a high enough nutritional content which has the potential to be developed into cheap, easy and simple non-synthetic media in making. The purpose of this study was to determine whether the agar media contained nutrient from cowpea and pigeonpea water can be used as a alternative for nutrient agar for the growth of Escherchia coli and Staphylococcus aureus bacteria. This research is a true experiment with posttest-only control design. The growth rate of S. aureus bacteria on pigeonpea medium, cowpea medium, nutrient agar medium, were 164 CFU/mL (SD=3,13), 161 CFU/mL (SD=3,02) and 164 CFU/mL (SD=3,21), respectively. The average growth of E. coli on cowpea medium, pigeonpea medium, and nutrient agar control medium were 163 CFU/mL (SD=2,79), 167 CFU/mL (SD-2,63) and 164 CFU/mL (SD=2,75) respectively. Test results ANOVA between pigeonpea medium, cowpea medium and nutrient medium in order to obtain p value = 0.145 (p> 0.05) for the growth of E. coli bacteria and p value = 0.393 (p> 0.05) for growth S. aureus. It was concluded that there was no difference between the number of bacterial colonies of E. coli and S. aureus on three medium. The pigeonpea medium and cowpea can be used to grow and alternative nutrient agar in order to grow bacteria E. coli and S. aureus.

Polystyrene Nanoplastic Behavior and Toxicity on Crustacean Daphnia magna: Media Composition, Size, and Surface Charge Effects

Concerns about the possible ecotoxicological implications of nano-sized plastic materials in the freshwater environment are growing with the increasing use of plastic materials. The present study focuses on the behavior and effects of amidine-functionalized polystyrene (NPLs) of 20, 40, 60, and 100-nm-size in freshwaters and different synthetic media. Daphnia magna was exposed to increasing concentrations from 0.5 to 30 mg/L (and from 0.5 to 100 mg/L for 100-nm-sized NPLs). The results revealed no significant aggregation in ultra-pure water, culture media, and synthetic water. In the presence of natural organic matter, NPLs of 20 and 40 nm displayed better stability in both freshwater and synthetic media, whereas a significant aggregation of 60 and 100 nm PS NPLs was found. All the studied PS NPLs with size between 20 and 100 nm exhibited acute toxicity to D. magna. The observed 48-h immobilization strongly depended on the primary size of PS NPLs, with 20 and 40-nm-size PS NPLs inducing a stronger effect in both freshwaters and synthetic media. Water quality variables such as pH, cation and anion composition, and DOC were of secondary importance. The results of the present study confirmed the toxicity of NPLs of different sizes to crustaceans in natural freshwater and synthetic media and demonstrated the importance of the primary size of NPLs in the behavior and effects of NPLs.