Seventy-one percent of the earth surfaces is covered by oceans. Water therefore is an important habitat for microorganisms and the other living beings. A consistent microbial biodiversity is present in water from phototrophs to chemioorganotrophs. The complex relationships between different microorganisms and the environment are often modified by organic, chemical and physic contaminations. The input of organic material can determine pathogenic pollution. The presence of pathogens has to be monitored to eliminate serious problems for animal and human health. Water, in fact, can be a vehicle direct (drinking water) or indirect (irrigation water) for microbial pathogens | Il 71% della superficie terrestre è costituito dagli oceani. L'acqua pertanto è un importante ambiente per i microrganismi, oltre che per tutti gli altri esseri viventi. Una grande varietà di tipi microbici colonizzano l'habitat acquatico, dai fototrofi ai chemiorganotrofi. Le dinamiche che si creano fra i diversi componenti microbici e l'ambiente sono spesso alterate da contaminazioni organiche, chimiche e fisiche. L'immissione di materiale organico può anche essere fonte di inquinamento di microrganismi patogeni la cui presenza va monitorata al fine di evitare seri problemi alla salute umana e animale. L'acqua, infatti, può rappresentare un veicolo di trasferimento, sia diretto (acqua potabile), sia indiretto (acque di irrigazione), di microrganismi patogeni

The objective of this study was to determine the changes in water activity and moisture content in the dry fermented sausages Herkules, a typical multicomponent food, during ripening and storage. The sausages were made with lean beef, lean pork, pork fat, nitrite salt mixture, and sugars, and fermented with two starter cultures (Pediococcus pentosaceus + Staphylococcus carnosus and S. carnosus + S. xylosus + Lactobacillus farciminis). The samples were taken and tested during ripening (21 days) and storage (91 days). The water activity was measured by indirect manometric method in a static environment, the moisture content by halogen dryer. The water activity and moisture content decreased considerably, but very irregularily during the ripening, whereas they declined only slowly and linearly during the storage. The decrease during the storage was expressed by mathematical equations describing the changes of water activity and moisture content in function of the time. The use of different starter cultures had no influence on the two variables studied.

Most fossil fuel-derived polymers used for food packaging are non-biodegradable and induce pollution by microplastic, calling for safer material. Here we review microbial production and applications of pullulan, a unique biopolymer produced by fermentation of agro-residues, using a strain named Aureobasidium pullulan. Chemically modified pullulan is widely used in food, pharmaceuticals, biomedical, and cosmetics. Compared to conventional polymers, pullulan increases the tensile strength 6–37-folds and increases the bioadhesion time 72–120-folds. Pullulan has been recently produced from agro-based waste with yields as high as 58-69 g/L.

Food waste is considered a serious global societal problem. How to degrade of food waste in a green and effective way has been to a hot topic. In this work, a method with hot water extraction pretreatment of food waste was investigated and optimized. Under the optimal conditions, more than half of the solid food waste could be transferred to soluble sugars. Meanwhile, in order to improve the tolerance of Rhizopus arrhizus on the food waste hydrolysate, UV combined with chemical mutagenesis were carried out, and a mutant of Rhizopus RH-7-13-807 was obtained. With the mutant strain, the yield of fumaric acid fermented from food waste increased to 1.8 times compared with the original strain, and 23.94 g/L fumaric acid was obtained from the fermentation. Besides, the COD of food waste was evaluated for the degradation of food waste by the Rhizopus RH-7-13-807. The process would decrease the quantity of food waste to be disposed of, and benefit the environment.

The work is intended to explore the suitability of underutilized coconut water (a byproduct of food industry) for the production of exopolysaccharides (EPS) by Agrobacterium sp. CFR 24. Besides checking the suitability of coconut water for the production of water-soluble (WS) and water-insoluble (WIS) EPS, certain fermentation parameters, such as initial pH, incubation period and kinetics of EPS production were investigated. The coconut water medium was found to support the production of both types of EPS. The optimal initial pH and temperature was found to be 6·0 and 30°C, respectively. In shake flask (150 rev min[superscript [-]1]) studies, high-cell density inoculum resulted in the production of 11·50 g l[superscript [-]1] of WIS-EPS and 4·01 g l[superscript [-]1] WS-EPS after 72 and 96 h of fermentation, respectively. Coconut water was found suitable for the production of microbial EPS by Agrobacterium sp. CFR 24 strain. Under optimum conditions, it produced a good amount of WIS-EPS, which is comparable with that of the sucrose medium (11 g l[superscript [-]1]). This is the first report on the use of coconut water as a fermentation medium for the production of any microbial EPS. Besides producing value-added products, use of this food industry byproduct, which is often being drained out, can significantly reduce the problem of environmental pollution.

Accurate measurement of water activity (aw) is an important goal for the food industry because aw is a key parameter in microbial growth, biological reaction rates and physical properties. An experimental device was setup using air-product water balance to non-destructively estimate the time-course of mean aw at the food product surface under well-controlled airflow conditions. The device is especially suited for studying the ripening of cheeses and fermented meat products, where water fluxes exchanged between products and air are very low. The validation tests performed with aw-known model products showed that water fluxes of 10(−7) kg s−1 can be estimated with an accuracy better than 2% over very short periods of time, and that surface aw can be estimated with an absolute uncertainty of less than 0.01 aw units. A handful of cheese ripening trials illustrate the potential of the method, highlighting the effects of a low air velocity and high air RH on the water exchanges occurring at a cheese surface, thus demonstrating the strong surface sensitivity to external air conditions.

To replace existing high impact ammonia production technologies, a new sustainability-driven waste-based technology producing green ammonia with and without urea was devised using life cycle thinking and sustainable design principles, targeting efficiency, carbon emissions, water, and power use competitiveness. We have used life cycle assessment to determine whether cradle-to-gate, multiple configurations of the core waste-based processes integrating several carbon capture/utilization options can compete environmentally with other available ammonia technologies. Our waste-to-ammonia processes reduce potential impacts from abiotic depletion, human toxicity, and greenhouse gas (GHG) emissions relative to fossil-based and renewable technologies. Among the assessed technologies, coupling dark fermentation with anaerobic digestion and capturing CO₂ for sequestration or later use is most efficient for GHGs, water, and energy, consuming 27% less energy and reducing GHGs by 98% compared to conventional ammonia. Water use is 38% lower than water electrolysis and GHGs are 94% below municipal waste incineration routes per kg NH₃. Additionally, displacing conventional, high impact urea by integrating urea production from process CO₂ decreases life cycle environmental impacts significantly despite increased energy demand. On a fertilizer-N basis, the ammonia + urea configuration without dark fermentation performs best on all categories included. Methane and ammonia leakage cause nearly all life cycle impacts, indicating that failing to prevent leakage undermines the effectiveness of new technologies such as these. Our results show that a green ammonia/ammonia + urea process family as designed here can reduce waste and prevent the release of additional CO₂ from ammonia production while avoiding fossil-based alternatives and decreasing emissions from biogenic waste sources.

The purpose of this study was to investigate the impact of microaeration on the fermentation process during anaerobic co-digestion of brown water (BW) and food waste (FW). This was achieved by daily monitoring of reactor performance and the determination of its bacterial consortium towards the end of the study. Molecular cloning and sequencing results revealed that bacteria within phyla Firmicutes and Bacteriodetes represented the dominant phylogenetic group. As compared to anaerobic conditions, the fermentation of BW and FW under microaeration conditions gave rise to a significantly more diverse bacterial population and higher proportion of bacterial clones affiliated to the phylum Firmicutes. The acidogenic reactor was therefore able to metabolize a greater variety of substrates leading to higher hydrolysis rates as compared to the anaerobic reactor. Other than enhanced fermentation, microaeration also led to a shift in fermentation production pattern where acetic acid was metabolized for the synthesis of butyric acid.

With the aim of developing bioprocesses for waste valorization and a reduced water footprint, we optimized a two-step fermentation process that employs the oleaginous yeast Cutaneotrichosporon oleaginosus for the production of oil from liquid cheese whey permeate. For the first step, the addition of urea as a cost-effective nitrogen source allowed an increase in yeast biomass production. In the second step, a syrup from candied fruit processing, another food waste supplied as carbon feeding, triggered lipid accumulation. Consequently, yeast lipids were produced at a final concentration and productivity of 38 g/L and 0.57 g/L/h respectively, which are among the highest reported values. Through this strategy, based on the valorization of liquid food wastes (WP and mango syrup) and by recovering not only nutritional compounds but also the water necessary for yeast growth and lipid production, we addressed one of the main goals of the circular economy. In addition, we set up an accurate and fast-flow cytometer method to quantify the lipid content, avoiding the extraction step and the use of solvents. This can represent an analytical improvement to screening lipids in different yeast strains and to monitoring the process at the single-cell level.