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The aim of this study was to determine the effects of dietary supplementation with black cumin seed meal on growth performance parameters, coccidia oocyst counts, plasma biochemical parameters and cecal fermentation processes in growing rabbits. A total of 40 male Californian rabbits at 35 days of age were divided into two feeding groups: Control (complete rabbit diet) and Black cumin (2% of the complete diet was replaced with black cumin seed meal). Dietary supplementation with black cumin did not affect growth performance parameters, but it reduced coccidia oocyst counts in the feces of 63-day-old rabbits. Increased liver weight and elevated plasma albumin levels were noted in these rabbits. A significant decrease in small intestinal digesta viscosity was also observed in rabbits fed a diet supplemented with black cumin seed meal. The above change suppressed the formation of putrefactive compounds, i.e. ammonia and branched short-chain fatty acids (SCFA s) in the cecum, but it did not decrease the production of major SCFA s, i.e. acetic, propionic and butyric acids. The current study demonstrated that the dietary addition of 2% black cumin seed meal exerted a modulatory effect on gastrointestinal function, but it did not compromise microbial enzyme activity or SCFA production in the cecum.

The manufacture of bio-chemicals through the use of microbial fermentation and renewable feedstock has a number of well-known advantages linked to sustainability and reduced impacts on the environment. Markets for molecules produced with greener credentials are growing as consumers become more aware of what is in the formulated products they use every day. The use of solventogenic clostridia has now been re-commercialised for the production of bio-acetone and bio-n-butanol. The different impurity profiles of these bio-based molecules compared with petro-versions results in performance advantages in downstream derivatisation chemistry, giving an added benefit alongside sustainability advantages. Advances in genome editing now enable us to take the benefits observed with clostridial fermentation and apply them to the production of the next generation of bio-molecules.

Variations in industrial fermentation techniques have a significant impact on the fermentation of cigar tobacco leaves (CTLs), consequently influencing the aromatic attributes of the resulting cigars. The entire fermentation process of CTLs can be categorized into three distinct phases: phase 1 (CTLs prior to moisture regain), phase 2 (CTLs post-moisture regain and pile fermentation), and phase 3 (CTLs after fermentation and drying). These phases were determined based on the dynamic changes in microbial community diversity. During phase 2, there was a rapid increase in moisture and total acid content, which facilitated the proliferation of Aerococcus , a bacterial genus capable of utilizing reducing sugars, malic acid, and citric acid present in tobacco leaves. In contrast, fungal microorganisms exhibited a relatively stable response to changes in moisture and total acid, with Aspergillus , Alternaria , and Cladosporium being the dominant fungal groups throughout the fermentation stages. Bacterial genera were found to be more closely associated with variations in volatile compounds during fermentation compared to fungal microorganisms. This association ultimately resulted in higher levels of aroma components in CTLs, thereby improving the overall quality of the cigars. These findings reinforce the significance of industrial fermentation in shaping CTL quality and provide valuable insights for future efforts in the artificial regulation of secondary fermentation in CTLs. Key points • Industrial fermentation processes impact CTLs microbial communities. • Moisture and total acid content influence microbial community succession in fermentation. • Bacterial microorganisms strongly influence CTLs’ aldehyde and ketone flavors over fungi.

Bioethanol (fuel alcohol) has been produced by industrial alcoholic fermentation processes in Brazil since the beginning of the twentieth century. Currently, 432 mills and distilleries crush about 625 million tons of sugarcane per crop, producing about 27 billion liters of ethanol and 38.7 million tons of sugar. The production of bioethanol from sugarcane represents a major large-scale technology capable of producing biofuel efficiently and economically, providing viable substitutes to gasoline. The combination of immobilization of CO^sub 2^ by sugarcane crops by photosynthesis into biomass together with alcoholic fermentation of this biomass has allowed production of a clean and high-quality liquid fuel that contains 93% of the original energy found in sugar. Over the last 30 years, several innovations have been introduced to Brazilian alcohol distilleries resulting in the improvement of plant efficiency and economic competitiveness. Currently, the main scientific challenges are to develop new technologies for bioethanol production from first and second generation feedstocks that exhibit positive energy balances and appropriately meet environmental sustainability criteria. This review focuses on these aspects and provides special emphasis on the selection of new yeast strains, genetic breeding, and recombinant DNA technology, as applied to bioethanol production processes. [PUBLICATION ABSTRACT]

Syngas fermentation has been successfully implemented in commercial-scale plants and can enable the biochemical conversion of the driest fractions of biomass through synthesis gas (H 2 , CO 2 , and CO). The process relies on optimized acetogenic strains able to reach and maintain high productivity of ethanol and acetate. In parallel, microbial communities have shown to be the best choice for the production of valuable medium-chain carboxylates through anaerobic fermentation of biomass, demanding low technical complexity and being able to realize simultaneous hydrolysis of the substrate. Each of the two technologies benefits from different strong points and has different challenges to overcome. This review discusses the rationales for merging these two seemingly disparate technologies by analyzing previous studies and drawing opinions based on the lessons learned from such studies. For keeping the technical demands of the resulting process low, a case is built for using microbial communities instead of pure strains. For that to occur, a shift from conventional syngas-based to “syngas-aided” anaerobic fermentation is suggested. Strategies for tackling the intricacies of working simultaneously with communities and syngas, such as competing pathways, and thermodynamic aspects are discussed as well as the stoichiometry and economic feasibility of the concept. Overall, syngas-aided anaerobic fermentation seems to be a promising concept for the biorefinery of the future. However, the effects of process parameters on microbial interactions have to be understood in greater detail, in order to achieve and sustain feasible medium-chain carboxylate and alcohol productivity.

This study reports the development of a novel and simple formulation for probiotic delivery using chitosan-coated agar-gelatin gel particles. This methodology involves the production of agar-gelatin particles by thermally treating a mixture of agar and gelatin solutions at high temperatures (121 °C) and subsequently coating with chitosan. The particles were able to protect the probiotic strain Lactobacillus plantarum NCIMB 8826 during incubation for 2 h in simulated gastric fluid (pH 2), as no statistically significant loss (P > 0.05) in cell concentration was observed, and also resist dissolution in simulated intestinal fluid (pH 7.2). Interestingly, this protection is related to the fact that the intense thermal treatment affected the physicochemical properties of agars and resulted in the formation of a strong and tight polymer network, as indicated by the X-ray diffraction (XRD) analysis. Using an in vitro faecal batch fermentation model simulating the conditions of the distal part of the large intestine (pH 6.7–6.9), it was demonstrated by quantitative real-time PCR that the majority of L. plantarum cells were released from the agar-gelatin particles within 30 to 48 h. Overall, this work led to the development of a novel methodology for the production of probiotic-containing particles, which is simpler compared with current encapsulation technologies and has a lot of potential to be used for the controlled release of probiotics and potentially other solid bioactives in the large intestine.Key Points• Chitosan gel particles is a simple and scalable method of probiotic encapsulation.• Autoclaving agar-gelatin particles increases their stability at low pH.• Chitosan gel particles protected L. plantarum during gastrointestinal conditions.• Probiotics could be controlled release in the colon using chitosan gel particles.

The demand for 1,3-propanediol (1,3-PDO) has increased sharply due to its role as a monomer for the synthesis of polytrimethylene terephthalate (PTT). Although Clostridium butyricum is considered to be one of the most promising bioproducers for 1,3-PDO, its low productivity hinders its application on industrial scale because of the longer time needed for anaerobic cultivation. In this study, an excellent C. butyricum (DL07) strain was obtained with high-level titer and productivity of 1,3-PDO, i.e., 104.8 g/L and 3.38 g/(L•h) vs. 94.2 g/L and 3.04 g/(L•h) using pure or crude glycerol as substrate in fed-batch fermentation, respectively. Furthermore, a novel sequential fed-batch fermentation was investigated, in which the next bioreactor was inoculated by C. butyricum DL07 cells growing at exponential phase in the prior bioreactor. It could run steadily for at least eight cycles. The average concentration of 1,3-PDO in eight cycles was 85 g/L with the average productivity of 3.1 g/(L•h). The sequential fed-batch fermentation could achieve semi-continuous production of 1,3-PDO with higher productivity than repeated fed-batch fermentation and would greatly contribute to the industrial production of 1,3-PDO by C. butyricum.Key points• A novel C. butyricum strain was screened to produce 104.8 g/L 1,3-PDO from glycerol.• Corn steep liquor powder was used as a cheap nitrogen source for 1,3-PDO production.• A sequential fed-batch fermentation process was established for 1,3-PDO production.• An automatic glycerol feeding strategy was applied in the production of 1,3-PDO.

Traditional fermented foods are appreciated worldwide for their cultural significance and health-promoting properties. However, traditional fermentation production suffers from many obstacles such as microbial variability, varying quality, and lack of scalability. The implementation of smart fermentation technologies, including biosensors, the Internet of Things (IoT), artificial intelligence (AI), and machine learning (ML), hold the key to the optimization of microbial process control, enhance product consistency, and improve production efficiency. This review summarizes modern developments in real-time microbial monitoring, IoT, AI, and ML tailored to traditional fermented foods. Despite significant technical advancements, challenges related to high costs, the absence of standardized frameworks, and access restrictions for small producers remain substantial limitations. This review proposed a future direction prioritizing modular, scalable solutions, open-source innovation, and environmental sustainability. In alignment with Sustainable Development Goal 9 (Industry, Innovation, and Infrastructure), smart fermentation technologies advance sustainable industry through innovation and serve as a critical bridge between traditional craftsmanship and Industry 4.0, fostering inclusive development while preserving microbial biodiversity and cultural heritage.

High-titer fermentation is essential for economically viable biofuel production, yet even extensively-engineered microbes frequently stop producing ethanol before the substrate is exhausted. Furthermore, the causes of titer limitations are often poorly understood. A particular challenge is identifying the location of titer limitations in multi-enzyme pathways. Here, we show that MDF analysis can assist in the interpretation of metabolomic data. These findings provide a systems-level explanation for “stuck” fermentations in bacteria and identify thermodynamic driving force as a quantitative diagnostic metric that reveals where biological design targets emerge for metabolic engineering of ethanol and other bioproducts.

Two-phasic anaerobic digestion processes (hydrolysis/acidogenesis separated from acetogenesis/methanogenesis) can be used for biogas production on demand or a combined chemicals/bioenergy production. For an effective process control, detailed knowledge about the microbial catalysts and their correlation to process conditions is crucial. In this study, maize silage was digested in a two-phase process and interrelationships between process parameters and microbial communities were revealed. In the first-phase reactor, alternating metabolic periods were observed which emerged independently from the feeding frequency. During the L-period, up to 11.8 g L⁻¹ lactic acid was produced which significantly correlated to lactic acid bacteria of the genus Lactobacillus as the most abundant community members. During the alternating G-period, the production of volatile fatty acids (up to 5.3, 4.0 and 3.1 g L⁻¹ for propionic, n-butyric and n-caproic acid, respectively) dominated accompanied by a high gas production containing up to 28 % hydrogen. The relative abundance of various Clostridiales increased during this metabolic period. In the second-phase reactor, the metabolic fluctuations of the first phase were smoothed out resulting in a stable biogas production as well as stable bacterial and methanogenic communities. However, the biogas composition followed the metabolic dynamics of the first phase: the hydrogen content increased during the L-period whereas highest CH₄/CO₂ ratios (up to 2.8) were reached during the G-period. Aceticlastic Methanosaeta as well as hydrogenotrophic Methanoculleus and Methanobacteriaceae were identified as dominant methanogens. Consequently, a directed control of the first-phase stabilizing desired metabolic states can lead to an enhanced productivity regarding chemicals and bioenergy.