In silico analysis of antibiotic resistance genes in Lactiplantibacillus plan‐ tarum subsp. plantarum Kita‐3

The absence of transferable antibiotic resistance genes is required for the safety of commercial probiotics. Previous studies have found that antibiotic resistance genes on plasmids in Lactobacilli make them unsafe for food purposes due to the genes’ ability to transfer to pathogenic microorganisms. In contrast, bacteria from the Lactobacillaceae family are widely used as a probiotic. This study assessed the antibiotic susceptibility of Lactiplantibacillus plantarum subsp. plantarum Kita‐3 (previously known as Lactobacillus plantarum K‐3) isolated from Halloumi cheese using eight antibiotics. Genome sequencing was performed using the Illumina NovaSeq 6000 sequencing platform to detect the presence of antibiotic resistance genes on chromosomes and plasmids. L. plantarum subsp. plantarum Kita‐3 was resistant to clindamycin, streptomycin, and chloramphenicol but susceptible to tetracycline, ampicillin, kanamycin, erythromycin, and ciprofloxacin. Genome sequencing of L. plantarum subsp. plantarum Kita‐3 verified the presence of tetracycline, fluoroquinolones, β‐lactamase resistance genes, and multidrug resistance efflux. Kita‐3 had no transposable elements, gene transfer agents, plasmid‐related functions, or intact prophages. Overall, this study produced the antibiotic resistance profile of L. plantarum subsp. plantarum Kita‐3 to assess the risk of transferring antibiotic resistance genes to other bacteria. The study provides essential data on the safe use of L. plantarum subsp. plantarum Kita‐3 as probiotics

Cold Stress Response Genes of Lantiplantibacillus plantarum subsp. plantarum Mut-3 and Lantiplantibacillus plantarum subsp. plantarum Mut-7 Support the Ability to Survive in Low-Temperature Conditions

Probiotics are widely consumed in various food matrices to provide health benefits to the host. The viability of probiotic cells is influenced by several factors, including exposure to high temperatures during the production process and low temperatures during storage. In this study, we report the response to cold stress of Lantiplantibacillus plantarum subsp. plantarum Mut-3 and Mut-7 after 24 h of storage at 4°C and -20℃. The cell number of Lantiplantibacillus plantarum subsp. plantarum Mut-3 and Mut-7 in low-temperature condition had no significant differences than their initial number: 11.88 log CFU/ml and 11.62 log CFU/ml at 4°C; 11.51 log CFU/ml and 11.47 log CFU/ml at -20°C for Mut-3 and Mut-7 respectively. The results indicated the survival capacity of Lantiplantibacillus plantarum subsp. plantarum Mut-3 and Mut-7 at low temperatures. The genes encoding cold shock proteins for the response to cold stress were evaluated by genome sequencing. The CspA/CspC genes of Lantiplantibacillus plantarum subsp. plantarum Mut-3 and Mut-7 possibly play a role in maintaining cell resistance at low temperatures, since the genes products predicted to have conserved motifs in the RNA binding protein (RNP) -1 and RNP-2 responsible for cold response stress which are similar to those in other bacteria

Development of meat substitutes from filamentous fungi cultivated on residual water of Tempeh factories

In recent years, there has been an increased motivation to reduce meat consumption globally due to environmental and health concerns, which has driven the development of meat substitutes. Filamentous fungal biomass, commonly known as mycoprotein, is a potential meat substitute since it is nutritious and has filaments to mimic meat fibrils. The current study aimed to investigate the potential use of a cheap substrate derived from the food industry, i.e., residual water in a tempeh factory, for mycoprotein production. The type of residual water, nutrient supplementation, optimum conditions for biomass production, and characteristics of the mycoprotein were determined. The results showed that the residual water from the first boiling with yeast extract addition gave the highest mycoprotein content. The optimum growth condition was a pH of 4.5 and agitation of 125 rpm, and it resulted in 7.76 g/L biomass. The mycoprotein contains 19.44% (w/w) protein with a high crude fiber content of 8.51% (w/w) and a low fat content of 1.56% (w/w). In addition, the amino acid and fatty acid contents are dominated by glutamic acid and polyunsaturated fatty acids, which are associated with an umami taste and are considered healthier foods. The current work reveals that the residual boiling water from the tempeh factory can be used to produce high-quality mycoprotein.The authors wish to thank the innovative research grant of the Faculty of Agricultural Technology, Gadjah Mada University 3663/UN1/FTP.1.3/SET-D/KU/2022 for financial support of the project and the World Class Professor Program by the Directorate General of Higher Education, Research, and Technology, Ministry of Education, Culture, Research and Technology Republic of Indonesia 2965/E4/DT.04.03/2022 for the publication.info:eu-repo/semantics/publishedVersio

Effects of Spirulina platensis Addition on Growth of Lactobacillus plantarum Dad 13 and Streptococcus thermophilus Dad 11 in Fermented Milk and Physicochemical Characteristics of the Product

Abstract Background and Objective: Spirulina platensis includes excellent bioactive compounds, which provide health-promoting effects. However, use of Spirulina platensis in foods includes limitations due to its unpleasant flavor and taste for some people. Fermented milk products include typical taste and flavor of fresh acid and can be combined with Spirulina platensis. Probiotics of Lactobacillus plantarum Dad 13 and Streptococcus thermophilus Dad 11 isolated from traditional buffalo milks can be used as starter culture strains for the fermented milks. This study investigated lactic acid bacterial growth, acid production and physicochemical characteristics of the fermented milks with Spirulina platensis. Material and Methods: Milk fermentation was carried out using addition of various concentrations (0.15, 0.3, 0.45 and 0.6%) of Spirulina platensis powder and then microbial cell growth, acid production and antioxidant activity were investigated. Fermented milks with selected concentrations of Spirulina platensis were assessed within 24 h of fermentation at 37 °C using single and mixed cultures to study various aspects of cell growth, acid production, viscosity, water holding capacity and color. Results and Conclusion: Increases of Spirulina platensis concentrations in fermented milks increased the microbial cell growth, acid production and antioxidant activity. During milk fermentation by adding 0.3% of Spirulina platensis, cells propagated and total lactic acid bacteria and probiotic cell counts reached to respectively 8.73-9.19 and 8.92 log CFU ml-1 after 24 h. The titratable acidity reached to 1.08% and pH decreased to 4.41. Viscosity increased significantly after 12 h of fermentation, compared to the controls. Fermented milks with Spirulina platensis addition by Lactobacillus plantarum Dad 13 and Streptococcus thermophilus Dad 11 cultures can be developed as alternative functional fermented milk products. Conflict of interest: The authors declare no conflict of interest

Effect of fruit flavors on anaerobic digestion : inhibitions and solutions

Fruits are among the most important commodities in global trading due to its fundamental nutritional values. In 2012, the fruits supply was 115 kg/person/year, however, only 50 % of the fruits reached their consumers and the rest ended up as waste during the long fruit supply chain. The waste from fruits is mostly dumped or burned, creating a serious environmental problem. A more sustainable handling of the waste is therefore highly desirable. One of them is conversion of the fruits wastes into biogas through anaerobic digestion. One challenge with the conversion of fruits wastes into biogas is the presence of antimicrobial compounds in the fruits, which reduce the biogas yield or even cause a total failure of the process. Fruit flavors have been reported to have antimicrobial activity against several microorganisms and being responsible for the defense system in the fruits. However, there is only scarce information about the effect of fruit flavors on anaerobic digesting microbia. The objectives of the present thesis were: 1) to investigate the inhibitory activity of the fruit flavors on anaerobic digestion; 2) to remove the flavor compound by pretreatment; and 3) to protect the cell from the flavor compounds using a membrane bioreactor. The inhibitory activity of the fruit flavors was examined from different groups of flavors by adding a single flavor compound into the batch anaerobic digesting system, at three different concentrations. Among the flavors added, myrcene and octanol were found to exhibit a strong inhibitory activity, with 50 % reduction of the methane production at low concentrations, ca. 0.005–0.05 %. These flavors can be found in oranges, strawberries, grapes, plums, and mangoes. The other flavors tested showed moderate and low inhibitory activity, which might not affect the anaerobic digestion of the fruits wastes. In order to overcome the inhibitory effects of the fruit flavor, two approaches were proposed in this thesis, namely, fruit flavor removal by leaching pretreatment and cell protection from fruit flavor using a membrane bioreactor. Orange peel waste and D-limonene were used as a model of fruit waste and inhibitor, respectively. The leaching pretreatment uses solvent to extract the limonene from the orange peel. The methane yield increased by 356 % from 0.061 Nm3/kg VS to 0.217 Nm3/kg VS, by pretreating the peel using hexane with peel and a hexane ratio of 1:12 at room temperature for 10 min. Alternative to limonene removal, the cells were encased in a hydrophilic membrane, which is impermeable to hydrophobic limonene. This method yielded more than six times higher methane yield, compared to the free cell. At the highest organic loading rate, examined in this work, 3 g VS/L/day, the methane yield of the reactor containing the free cell was only 0.05 Nm3/kg VS, corresponding to 10 % of the theoretical yield, whereas 0.33 Nm3/kg VS methane yield was achieved using a membrane bioreactor corresponding to 75 % of the theoretical yield.Thesis for the degree of Doctor of Philosophy at the University of Borås to be publicly defended on November 27th 2014, 10.00 a.m. in room E310, University of Borås, Allégatan 1, Borås.</p

CHITOSAN AND ETHANOL PRODUCTION FROM DIFFERENT CARBON SOURCES USING FUNGI ISOLATED FROM INDONESIAN TRADITIONAL TEMPE STARTER

In searching for simultaneous chitosan and ethanol producing microorganisms, mixed cultures of fungi for making tempe (a fermented soy bean food originally from Indonesia) or tempe starter was examined. The fungi were isolated from two different mixed cultures of fungi grown in Hibiscus and Tectona gandis leaves called as Usar and Laru. Thirty two isolates were obtained and they were tentarively identified belong to genus Rhizopus, Mucor, Rhizomucor, and Absidia. Each fungus was cultivated on glucose as the carbon source. Chitosan was successfully extracted from the cell wall of all isolates with the yield ranging between 0.44 to 0.79 g/g of alkali insoluble material (AIM). The degree of deacetylation of all extracted chitosans varied greatly from 0.96 to 61.3%. All isolates produced ethanol as the major metabolites with the maximum yield varied between 0.26 and 0.41g ethanol/g glucose. Glycerol was the next major metabolites, followed by lactic acid. Cultivation on agar plates containing xylose, cellobiose, and cellulose showed that the highest growth rate was observed on xylose followed by cellobiose and cellulose. Two isolates which were identified as Rhizomucor were used for further investigation by cultivation on liquid medium containing glucose, xylose and mixed sugar. The results showed that sugar sources affect the yields of chitosan and ethanol as well as the degree of deacetylation of the chitosan produced. Fourier Transform Infra Red Spectroscopy analysis results showed that all chitosan extracted from the Isolates grown on different sugar sources have similar spectrum with a commercial chitosan

The role of filamentous fungi in advancing the development of a sustainable circular bioeconomy

Human activities generate enormous amounts of organic wastes and residues. Filamentous fungi (FF) are able to grow on a broad range of substrates and survive over a wide spectrum of growth conditions. These characteristics enable FF to be exploited in biorefineries for various waste streams. Valorization of food industry byproducts into biomass and various arrays of value-added products using FF creates promising pathways toward a sustainable circular economy. This approach might also contribute to reaching the sustainable development goals set by the United Nations, particularly for zero hunger as well as affordable and clean energy. This paper presents the application of filamentous fungi in food, feeds, fuels, biochemicals, and biopolymers. The nutritional values, health benefits, and safety of foods derived from byproducts of food industries are also addressed. The technoeconomical feasibilities, sustainability aspects and challenges and future perspectives for biorefineries using filamentous fungi are discussed

Biogas Production from Citrus Waste by Membrane Bioreactor

Rapid acidification and inhibition by d-limonene are major challenges of biogas production from citrus waste. As limonene is a hydrophobic chemical, this challenge was encountered using hydrophilic polyvinylidine difluoride (PVDF) membranes in a biogas reactor. The more sensitive methane-producing archaea were encapsulated in the membranes, while freely suspended digesting bacteria were present in the culture as well. In this membrane bioreactor (MBR), the free digesting bacteria digested the citrus wastes and produced soluble compounds, which could pass through the membrane and converted to biogas by the encapsulated cell. As a control experiment, similar digestions were carried out in bioreactors containing the identical amount of just free cells. The experiments were carried out in thermophilic conditions at 55 °C, and hydraulic retention time of 30 days. The organic loading rate (OLR) was started with 0.3 kg VS/m3/day and gradually increased to 3 kg VS/m3/day. The results show that at the highest OLR, MBR was successful to produce methane at 0.33 Nm3/kg VS, while the traditional free cell reactor reduced its methane production to 0.05 Nm3/kg VS. Approximately 73% of the theoretical methane yield was achieved using the membrane bioreactor

Effect of ester compounds on biogas production: beneficial or detrimental?

Esters are major flavor compounds in fruits, which are produced in high volume. The widespread availability of these compounds in nature attracts interest on their behavior in anaerobic digestion in waste and wastewater treatments. The aim of this work was to study the effects of various esters at different concentrations in anaerobic digestion followed by determination of their minimum inhibitory concentration (MIC), and to study the effect of chain length of functional group and alkyl chain of ester on methane production. Addition of methyl butanoate, ethyl butanoate, ethyl hexanoate, and hexyl acetate at concentration up to 5 g L−1 increased methane production, while their higher concentrations inhibited the digestion process. The MIC values for these esters were between 5 and 20 g L−1. Except hexyl acetate, the esters at concentration 5 g L−1 could act as sole carbon source during digestion. For ethyl esters, increasing number of carbon in functional group decreased methane production. For acetate esters, alkyl chain longer than butyl inhibited methane production. Effect of ester on methane production is concentration-dependent

Improvement of Biogas Production from Orange Peel Waste by Leaching of Limonene

Limonene is present in orange peel wastes and is known as an antimicrobial agent, which impedes biogas production when digesting the peels. In this work, pretreatment of the peels to remove limonene under mild condition was proposed by leaching of limonene using hexane as solvent. The pretreatments were carried out with homogenized or chopped orange peel at 20–40°C with orange peel waste and hexane ratio (w/v) ranging from 1 : 2 to 1 : 12 for 10 to 300 min. The pretreated peels were then digested in batch reactors for 33 days. The highest biogas production was achieved by treating chopped orange peel waste and hexane ratio of 12 : 1 at 20°C for 10 min corresponding to more than threefold increase of biogas production from 0.061 to 0.217 m3methane/kg VS. The solvent recovery was 90% using vacuum filtration and needs further separation using evaporation. The hexane residue in the peel had a negative impact on biogas production as shown by 28.6% reduction of methane and lower methane production of pretreated orange peel waste in semicontinuous digestion system compared to that of untreated peel