New insights into Chlorella vulgaris applications

Environmental pollution is a big challenge that has been faced by humans in contemporary life. In this context, fossil fuel, cement production, and plastic waste pose a direct threat to the environment and biodiversity. One of the prominent solutions is the use of renewable sources, and different organisms to valorize wastes into green energy and bioplastics such as polylactic acid. Chlorella vulgaris, a microalgae, is a promising candidate to resolve these issues due to its ease of cultivation, fast growth, carbon dioxide uptake, and oxygen production during its growth on wastewater along with biofuels, and other productions. Thus, in this article, we focused on the potential of Chlorella vulgaris to be used in wastewater treatment, biohydrogen, biocement, biopolymer, food additives, and preservation, biodiesel which is seen to be the most promising for industrial scale, and related biorefineries with the most recent applications with a brief review of Chlorella and polylactic acid market size to realize the technical/nontechnical reasons behind the cost and obstacles that hinder the industrial production for the mentioned applications. We believe that our findings are important for those who are interested in scientific/financial research about microalgae.

Using custom-built primers and nanopore sequencing to evaluate CO-utilizer bacterial and archaeal populations linked to bioH2 production

The microbial community composition of five distinct thermophilic hot springs was effectively described in this work, using broad-coverage nanopore sequencing (ONT MinION sequencer). By examining environmental samples from the same source, but from locations with different temperatures, bioinformatic analysis revealed dramatic changes in microbial diversity and archaeal abundance. More specifically, no archaeal presence was reported with universal bacterial primers, whereas a significant archaea presence and also a wider variety of bacterial species were reported. These results revealed the significance of primer preference for microbiomes in extreme environments. Bioinformatic analysis was performed by aligning the reads to 16S microbial databases for identification using three different alignment methods, Epi2Me (Fastq 16S workflow), Kraken, and an in-house BLAST tool, including comparison at the genus and species levels. As a result, this approach to data analysis had a significant impact on the genera identified, and thus, it is recommended that use of multiple analysis tools to support findings on taxonomic identification using the 16S region until more precise bioinformatics tools become available. This study presents the first compilation of the ONT-based inventory of the hydrogen producers in the designated hot springs in Türkiye.

Utilizing response surface methodology to evaluate the process parameters of indigenous cucumber fermentation

Commercial pickled cucumbers are produced in variety of salt concentrations including brines up to 15% sodium chloride due to the preventive nature of the salt towards microbial growth. Although it is deemed necessary for manufacturers to utilize high amounts of salts to prolong shelf life, the high content creates a burden for the growth of beneficial microorganisms including probiotics. In this study, the production of naturally fermented cucumbers and their microbial viability were tested with the help of an experimental design tool, Box-Behnken Design (BBD), to evaluate the optimal conditions for the production process and to maintain the highest viability of potential beneficial microorganisms during storage. Accordingly, the operational conditions including salt concentration (2, 5, or 8%), fermentation temperature (20, 25, or 30 °C), and brine filling (pretreatment) temperature (80, 85, or 90 °C) were optimized with a significant fit to a quadratic model (p < 0.05). The trends for sugar consumption and total acid production were monitored to demonstrate the correlation between the above-mentioned operational parameters for the fermentation process of pickled cucumbers with indigenous microorganisms. Overall, 5% salt content, 70 °C filling temperature and 25 °C fermentation medium was determined to maintain over 6 log cfu/mL viability. The results represent a valuable contribution to the pickle industry including a know-how of process parameters.

A comprehensive review on the development of probiotic supplemented confectioneries

Probiotics are living organisms that have beneficial effects on host by regulating the microbial balance of the intestinal system. While probiotics are naturally found in yogurt and other fermented foods, they can also be added to many products. Although mostly in dairy products, it is possible to see examples of food products supplemented by probiotics in bakeries, chocolates and confectioneries. Nowadays, the COVID-19 pandemic that the world suffers increased the demand for such functional food products including probiotics. Due to probiotics having potential effects on strengthening the immune system, confectioneries supplemented by probiotics were comprehensively discussed in this review together with the suggestion of a novel gelly composition. The suggested formulation of the product is a gel-like snack contains natural ingredients such as carrot, lemon juice and sugar provided from apples. This research review article provided a guide together with the recommendations for potential probiotic research in candy and confectionery industry.

Hydrogen Production by Immobilized Cells of Clostridium intestinale Strain URNW Using Alginate Beads

Biological hydrogen (H₂) is a promising candidate for production of renewable hydrogen. Using entrapped cells rather than conventional suspended cell cultures for the production of H₂ offers several advantages, such as improved production yields related to higher cell density, and enhanced resistance to substrate and end-product inhibition. In this study, H₂ production by a novel isolate of Clostridium intestinale (strain URNW) was evaluated using cells entrapped within 2% calcium-alginate beads under strictly anaerobic conditions. Both immobilized cells and suspended cultures were studied in sequential batch-mode anaerobic fermentation over 192 h. The production of H₂ in the headspace was examined for four different initial cellobiose concentrations (5, 10, 20, and 40 mM). Although a lag period for initiation of the fermentation process was observed for bacteria entrapped within hydrogel beads, the immobilized cells achieved both higher volumetric production rates (mmol H₂/(L culture h)) and molar yields (mol H₂/mol glucose equivalent) of H₂ compared with suspended cultures. In the current study, the maximum cellobiose consumption rate of 0.40 mM/h, corresponding to 133.3 mg/(L h), was achieved after 72 h of fermentation by immobilized cells, generating a high hydrogen yield of 3.57 mol H₂/mol cellobiose, whereas suspended cultures only yielded 1.77 mol H₂/mol cellobiose. The results suggest that cells remain viable within the hydrogels and proliferated with a slow rate over the course of fermentation. The stable productivity of immobilized cells over 8 days with four changes of medium depicted that the immobilized cells of the isolated strain can successfully yield higher hydrogen and lower soluble metabolites than suspended cells suggesting a feasible process for future applications for bioH₂ production.

Development and Comparative Evaluation of a Novel Fermented Juice Mixture with Probiotic Strains of Lactic Acid Bacteria and Bifidobacteria

As being a rapidly developing area, the production of nondairy-based functional beverages continues to accelerate considerably. In the present study, the probiotification of a mixture of the juices of Jerusalem artichoke, pineapple, pumpkin, spinach, and cucumber has been utilized for the development of probiotic fruit-vegetable juice. Lactic acid fermentation was comparatively performed by Lactobacillus acidophilus DSM13241, Lacticaseibacillus paracasei subsp. paracasei ATCC 55544, Lacticaseibacillus rhamnosus ATCC53103, Lactiplantibacillus plantarum DSMZ 20174, and Bifidobacterium animalis subsp. lactis BB-12 at 37 °C for 24 h. Following, the fermented products were kept at 8 °C for 45 days, and viability of the strains were tested during the storage period, which refers 15th, 30th, and 45th days. During fermentation, the number of viable probiotic cells increased up to 9.42 log CFU/mL. Consequently, at the end of storage, all strains exhibited an acceptable amount of viability along with L. rhamnosus ATCC 53103 with the highest value reaching 9.30 log CFU/mL. The beverage was successfully scaled up in a bioreactor followed by a sensory evaluation. Statistical analysis revealed that there is a significant difference (p < 0.05) on how much the product was enjoyed between all tested samples with an average score of 3.8 out of 7.0. Thus, flavor and consumer acceptability of the beverage was improved with the addition of 30% of apple juice. The results affirm that the proposed novel fermented mixture of Jerusalem artichoke, pineapple, pumpkin, spinach, and cucumber stands as a promising functional product to be placed in the beverage market.