Study of the significance of the ph of the substrate of the biogas installation during treating it with a low-frequency electromagnetic field

The article considers the issue of studying the value of pH, substrate in the process of methane fermentation in the mesophilic regime and the influence of the electromagnetic field of industrial frequency. The aim is to investigate the influence of electromagnetic fields on the pH value of the substrate during fermentation. Different types of microorganisms are involved in the process of methanogenesis, and the decisive role in it is played by methane-forming archaea, which are most sensitive to pH and should be in the range of 6.5 - 8. Therefore, it is necessary to check the effect of low frequency electromagnetic field on substrate pH. The study was performed for 25 days on two substrates, one of which was exposed to a low-frequency electromagnetic field with an electromagnetic induction of 3.5 mT. The research results show that the pH value of the substrate exposed to the electromagnetic field during the methane fermentation process was within acceptable limits, and the second substrate decreased, that is, it was acidified. Key words: methane fermentation, substrate, pH value, electromagnetic field

Structural Characterization and Antioxidant Activity of Exopolysaccharide from Soybean Whey Fermented by Lacticaseibacillus plantarum 70810

Soybean whey is a high-yield but low-utilization agricultural by-product in China. In this study, soybean whey was used as a substrate of fermentation by Lacticaseibacillus plantarum 70810 strains. An exopolysaccharide (LPEPS-1) was isolated from soybean whey fermentation by L. plantarum 70810 and purified by ion-exchange chromatography. Its preliminary structural characteristics and antioxidant activity were investigated. Results show that LPEPS-1 was composed of mannose, glucose, and galactose with molar ratios of 1.49:1.67:1.00. The chemical structure of LPEPS-1 consisted of →4)-α-D-Glcp-(1→, →3)-α-D-Galp-(1→ and →2)-α-D-Manp-(1→. Scanning electron microscopy (SEM) revealed that LPEPS-1 had a relatively rough surface. In addition, LPPES-1 exhibited strong scavenging activity against DPPH and superoxide radicals and chelating ability on ferrous ion. This study demonstrated that soybean whey was a feasible fermentation substrate for the production of polysaccharide from L. plantarum 70810 and that the polysaccharide could be used as a promising ingredient for health-beneficial functional foods.

SYNTHESIS L-LACTIC ACID FROM FERMENTATION OF CASSAVA PULP BY USING TEMPEH INOCULUM

SYNTHESIS L-LACTIC ACID FROM FERMENTATION OF CASSAVA PULP BY USING TEMPEH INOCULUM. This study used cassava waste pulp as a fermentation substrate to produce lactic acid using a tempeh inoculum. Tempeh inoculum is a mixed culture of Rhizopus with Rhizopus oligosporus as the primary fungus. Lactic acid is an organic acid most widely used in the food, pharmaceutical, cosmetic and chemical industries. One of the important uses of lactic acid is as a raw material for producing Polylactic Acid (PLA) biopolymers, namely polymers that can decompose naturally in a relatively fast time. The analysis was performed using the Response Surface Methodology (RSM) method and the Box Behnken Design (BBD) experimental design with substrate concentration parameters, inoculum concentration, and incubation time on lactic acid. The fermentation process is carried out using a flask shaker at a temperature of 30 ºC, pH 6.0, and a rotational speed of 150 rpm. The optimum yield for lactic acid is 6.65 g/L. It was acquired at substrate 20 g/L, inoculum concentration 0.30 % (w/v) at an incubation time of 72 hours.

THE CHARACTERISTICS OF SAGO FROND SAP FROM TWO SELECTED GROWTH STAGES; ANGKAT PUNGGUNG AND UPONG MUDA PALMS

Sago frond is produced in abundance upon harvesting of the sago palms for starch extraction, hence need to be utilized and developed into beneficial products. In this study, the sap which contains sugars and starch is obtained by roller crushing the skinned frond for use as fermentation medium. Fronds from different growth stages (namely Angkat punggung and Upong muda) and different positions within the rosette (inner and outer circle) of the sago palm were studied. Based on the results, the outer circle frond of Upong muda palm gave the highest volume of sap at 290mL/kg which equivalent to 1600 mL/frond. On top of that, sago frond sap has an acidic pH, with glucose as major sugar component and contained various kinds of minerals like calcium, potassium and manganese. All fronds from different growth stages contain glucose between 28-68 g/L and xylose 21-29 g/L, respectively. After 21 days of storage, it can be concluded that the amount of reducing sugars and starch in all samples obtained from different growth stages remained almost unchanged from the original. Subsequently after this study, both fresh and stored sago frond sap can be used as a fermentation substrate without any modification.

Seaweeds as a Fermentation Substrate: A Challenge for the Food Processing Industry

Seaweeds are gaining momentum as novel and functional food and feed products. From whole consumption to small bioactive compounds, seaweeds have remarkable flexibility in their applicability, ranging from food production to fertilizers or usages in chemical industries. Regarding food production, there is an increasing interest in the development of novel foods that, at the same time, present high nutritious content and are sustainably developed. Seaweeds, because they require no arable land, no usage of fresh water, and they have high nutritious and bioactive content, can be further explored for the development of newer and functional food products. Fermentation, especially performed by lactic acid bacteria, is a method used to produce functional foods. However, fermentation of seaweed biomass remains an underdeveloped topic that nevertheless demonstrates high potential for the production of new alimentary products that hold and further improve the organoleptic and beneficial properties that these organisms are characterized for. Although further research has to be deployed in this field, the prebiotic and probiotic potential demonstrated by fermented seaweed can boost the development of new functional foods.

Manuka Honey with Varying Levels of Active Manuka Factor (AMF) Ratings as an Anaerobic Fermentation Substrate for Limosilactobacillus reuteri DPC16

Manuka honey is known for its strong antibacterial effect against pathogens but can promote probiotic growth in certain conditions. In a two-factor ANOVA study, AMFTM Manuka honey (Active Manuka Factor: 05+, 10+, 15+ and 20+) was utilised as a substrate for probiotic Limosilactobacillus reuteri DPC16 in an anaerobic batch fermenter for 36 h. The biomass growth in MRS broth was noticeably higher with AMF Manuka honey than invert syrup and control samples without any additional sweetener source. The pH value was significantly lowered below 4.0 only in the AMF samples with the formation of lactic acid as the major metabolite. Other beneficial short-chain fatty acids (SCFA), such as acetic, succinic, and propionic acids, produced during the fermentation, along with the honey saccharides, were quantified by two-dimensional (2-D) nuclear magnetic resonance (NMR) spectroscopy. A significantly (p < 0.05) high biomass in AMF 20+ sample after 36 h, can partly be attributed to the high total sugar and oligosaccharide content in the honey. Importantly, however, no statistically significant difference was observed in the recorded major fermentation outcomes for the different AMF levels. The results, nevertheless, indicate the potential prebiotic efficacy of Manuka honey as a fermentation substrate for the lactobacilli probiotic strain.

Kombucha based synbiotic beverage using Yacon (Smallanthus sonchifolius) as a fermentation substrate: development and sensorial analysis

Probiotic and prebiotic beverages are promoters of the growth and maintenance of healthy intestinal microbiota composition. However, a drink that gathers the therapeutic attributes of Yacon with symbiotic multiple yeast-bacteria colonies, like Kombucha, has not yet been explored and appears to be potentially beneficial for human health. The objectives of this work were to develop a low-sugar Kombucha beverage using Yacon as fermentation substrate, labelled as Yacon-Kombucha (YK), with physical-chemical properties and sensorial acceptability compatible with the traditional Sugar-Kombucha (SK). Two beverages were prepared following standard procedures and fermented for 14 days. The pH, acidity, Brix and glucose content were evaluated at days 0, 4, 7, 9 and 14. The sensorial panel used a hedonic scale of 7 points considering colour, aroma, taste and global acceptability attributes for SK and YK final product. At the end of fermentation, obtained were beverages in which YK was less acidic and had the lowest glucose content when compared to SK. The sensorial analysis revealed no significant differences between the two samples for the tested attributes, also no rejection was observed. However, the scores received for both drinks were moderate, with the Index of acceptability for SK as 75% and YK 72%. Improvements in the aroma and taste are necessary for an accessible yacon-Kombucha beverage. The development of a low-sugar synbiotic beverage was possible and it may present benefits to gut microbiota and other health properties and can be consumed by individuals with diabetes.

A Review on the Utilization of Lignin as a Fermentation Substrate to Produce Lignin-Modifying Enzymes and Other Value-Added Products

The lignocellulosic biomass is comprised of three major components: cellulose, hemicellulose, and lignin. Among these three, cellulose and hemicellulose were already used for the generation of simple sugars and subsequent value-added products. However, lignin is the least applied material in this regard because of its complex and highly variable nature. Regardless, lignin is the most abundant material, and it can be used to produce value-added products such as lignin-modifying enzymes (LMEs), polyhydroxyalkanoates (PHAs), microbial lipids, vanillin, muconic acid, and many others. This review explores the potential of lignin as the microbial substrate to produce such products. A special focus was given to the different types of lignin and how each one can be used in different microbial and biochemical pathways to produce intermediate products, which can then be used as the value-added products or base to make other products. This review paper will summarize the effectiveness of lignin as a microbial substrate to produce value-added products through microbial fermentations. First, basic structures of lignin along with its types and chemistry are discussed. The subsequent sections highlight LMEs and how such enzymes can enhance the value of lignin by microbial degradation. A major focus was also given to the value-added products that can be produced from lignin.