Exopolysaccharide production by Lactobacillus confusus TISTR 1498 using coconut water as an alternative carbon source: the effect of peptone, yeast extract and beef extract

Coconut water (CW) is a by-product of food industry and has little value in Thailand. It is usually discarded as a wasteinto the environment. Consequently, we developed a value added process of exopolysaccharide (EPS) production usingLactobacillus confusus TISTR 1498 and coconut water. The effect of three expensive supplements (peptone, yeast extractand beef extract) on EPS and biomass production was investigated at 35°C for 24 h. Using a mod-MRS-CW medium, preparedby replacing the de-ionized water with 100% CW and supplemented with 20 g/l crystalline sucrose and a reduced quantity(50%) of the three expensive supplements (5 g/l of peptone, 2.5 g/l of yeast extract, and 2.5 g/l of beef extract) gave thehighest yield of EPS (12.3 g/l). By optimizing the conditions for fermentation (pH 5.5, agitation speed at 50 rpm and initialsucrose concentration of 100 g/l), EPS yield increased up to 38.2 g/l. When compared with the modified MRS medium, themedium supplemented with CW was found to be suitable for the reduction of cost spent on the organic nitrogen and growthfactors (savings close to 50%)

The antiviral activity of bacterial, fungal, and algal polysaccharides as bioactive ingredients: Potential uses for enhancing immune systems and preventing viruses

Viral infections may cause serious human diseases. For instance, the recent appearance of the novel virus, SARS-CoV-2, causing COVID-19, has spread globally and is a serious public health concern. The consumption of healthy, proper, functional, and nutrient-rich foods has an important role in enhancing an individual's immune system and preventing viral infections. Several polysaccharides from natural sources such as algae, bacteria, and fungi have been considered as generally recognized as safe (GRAS) by the US Food and Drug Administration. They are safe, low-toxicity, biodegradable, and have biological activities. In this review, the bioactive polysaccharides derived from various microorganisms, including bacteria, fungi, and algae were evaluated. Antiviral mechanisms of these polysaccharides were discussed. Finally, the potential use of microbial and algal polysaccharides as an antiviral and immune boosting strategy was addressed. The microbial polysaccharides exhibited several bioactivities, including antioxidant, anti-inflammatory, antimicrobial, antitumor, and immunomodulatory activities. Some microbes are able to produce sulfated polysaccharides, which are wellknown to exert a board spectrum of biological activities, especially antiviral properties. Microbial polysaccharide can inhibit various viruses using different mechanisms. Furthermore, these microbial polysaccharides are also able to modulate immune responses to prevent and/or inhibit virus infections. There are many molecular factors influencing their bioactivities, e.g., functional groups, conformations, compositions, and molecular weight. At this stage of development, microbial polysaccharides will be used as adjuvants, nutrient supplements, and for drug delivery to prevent several virus infections, especially SARS-CoV-2 infection

Pretreatment and enzymatic hydrolysis optimization of lignocellulosic biomass for ethanol, xylitol, and phenylacetylcarbinol co-production using Candida magnoliae

Cellulosic bioethanol production generally has a higher operating cost due to relatively expensive pretreatment strategies and low efficiency of enzymatic hydrolysis. The production of other high-value chemicals such as xylitol and phenylacetylcarbinol (PAC) is, thus, necessary to offset the cost and promote economic viability. The optimal conditions of diluted sulfuric acid pretreatment under boiling water at 95°C and subsequent enzymatic hydrolysis steps for sugarcane bagasse (SCB), rice straw (RS), and corn cob (CC) were optimized using the response surface methodology via a central composite design to simplify the process on the large-scale production. The optimal pretreatment conditions (diluted sulfuric acid concentration (% w/v), treatment time (min)) for SCB (3.36, 113), RS (3.77, 109), and CC (3.89, 112) and the optimal enzymatic hydrolysis conditions (pretreated solid concentration (% w/v), hydrolysis time (h)) for SCB (12.1, 93), RS (10.9, 61), and CC (12.0, 90) were achieved. CC xylose-rich and CC glucose-rich hydrolysates obtained from the respective optimal condition of pretreatment and enzymatic hydrolysis steps were used for xylitol and ethanol production. The statistically significant highest (p ≤ 0.05) xylitol and ethanol yields were 65% ± 1% and 86% ± 2% using Candida magnoliae TISTR 5664. C. magnoliae could statistically significantly degrade (p ≤ 0.05) the inhibitors previously formed during the pretreatment step, including up to 97% w/w hydroxymethylfurfural, 76% w/w furfural, and completely degraded acetic acid during the xylitol production. This study was the first report using the mixed whole cells harvested from xylitol and ethanol production as a biocatalyst in PAC biotransformation under a two-phase emulsion system (vegetable oil/1 M phosphate (Pi) buffer). PAC concentration could be improved by 2-fold compared to a single-phase emulsion system using only 1 M Pi buffer

Inhibitory Effects of Saponin-Rich Extracts from <i>Pouteria cambodiana</i> against Digestive Enzymes α-Glucosidase and Pancreatic Lipase

Pouteria cambodiana is a perennial plant that has a wide distribution in tropical regions. It is commonly referred to as ’Nom-nang’ in the northern region of Thailand. The bark of this plant has been used for the purpose of promoting lactation among breastfeeding mothers. Moreover, P. cambodiana bark has a high nutraceutical potential due to the presence of saponins, which are secondary metabolites. The purpose of this study was to determine the optimal conditions for ultrasound-assisted extraction (UAE) of saponins from the bark of P. cambodiana and to assess the in vitro inhibitory activities of saponin-rich extracts. The most effective extraction conditions involved a temperature of 50 °C and a 50% concentration level of ethanol as the solvent, which allowed the extraction of saponin at a concentration of 36.04 mg/g. Saponin-rich extracts and their hydrolysates from P. cambodiana bark were evaluated for their ability to inhibit α-glucosidase and pancreatic lipase. The IC50 values for saponin- and sapogenin-rich extracts inhibiting α-glucosidase were 0.10 and 2.98 mg/mL, respectively. Non-hydrolysed extracts also had a stronger inhibitory effect than acarbose. In the case of pancreatic lipase, only the hydrolysed extracts exhibited inhibitory effects on pancreatic lipase (IC 50 of 7.60 mg/mL). Thus, P. cambodiana bark may be an applicable natural resource for preparing ingredients for functional products with inhibitory activity against α-glucosidase and pancreatic lipase. The phenolic contents, saponin contents, and antioxidant activities of the dried extract stored at a low temperature of 25 °C for 2 months showed the best stability, with more than 90% retention.</p

Bioethanol Production from Cellulose-Rich Corncob Residue by the Thermotolerant Saccharomyces cerevisiae TC-5

This study aimed to select thermotolerant yeast for bioethanol production from cellulose-rich corncob (CRC) residue. An effective yeast strain was identified as Saccharomyces cerevisiae TC-5. Bioethanol production from CRC residue via separate hydrolysis and fermentation (SHF), simultaneous saccharification and fermentation (SSF), and prehydrolysis-SSF (pre-SSF) using this strain were examined at 35–42 °C compared with the use of commercial S. cerevisiae. Temperatures up to 40 °C did not affect ethanol production by TC-5. The ethanol concentration obtained via the commercial S. cerevisiae decreased with increasing temperatures. The highest bioethanol concentrations obtained via SHF, SSF, and pre-SSF at 35–40 °C of strain TC-5 were not significantly different (20.13–21.64 g/L). The SSF process, with the highest ethanol productivity (0.291 g/L/h), was chosen to study the effect of solid loading at 40 °C. A CRC level of 12.5% (w/v) via fed-batch SSF resulted in the highest ethanol concentrations of 38.23 g/L. Thereafter, bioethanol production via fed-batch SSF with 12.5% (w/v) CRC was performed in 5-L bioreactor. The maximum ethanol concentration and ethanol productivity values were 31.96 g/L and 0.222 g/L/h, respectively. The thermotolerant S. cerevisiae TC-5 is promising yeast for bioethanol production under elevated temperatures via SSF and the use of second-generation substrates

Optimization of Ultrasonic-Assisted Bioactive Compound Extraction from Green Soybean (<i>Glycine max</i> L.) and the Effect of Drying Methods and Storage Conditions on Procyanidin Extract

Green soybean (Glycine max L.) seeds (GSS) are rich in various antioxidants and phytonutrients that are linked to various health benefits. Ultrasound-assisted extraction (UAE) technology was used for extracting the effective components from GSS. A response surface method (RSM) was used to examine the influence of liquid-to-solid ratio and extraction temperature on the bioactive compounds and antioxidant characteristics. The optimal conditions were a liquid-to-solid ratio of 25:1 and a UAE temperature of 40 °C. The observed values coincided well with the predicted values under optimal conditions. Additionally, the effects of drying methods on the procyanidins and antioxidant activities of GSS extract were evaluated. The spray-dried GSS extract contained the highest levels of procyanidins (21.4 ± 0.37 mg PC/g), DPPH (199 ± 0.85 µM Trolox eq/g), and FRAP (243 ± 0.26 µM Trolox eq/g). Spray drying could be the most time- and energy-efficient technique for drying the GSS extract. The present study also assessed the effects of storage temperature and time on procyanidins and antioxidant activities in GSS extract powder. Procyanidins were found to degrade more rapidly at 45 °C than at 25 °C and 35 °C. Storage under 25 °C was appropriate for maintaining the procyanidin contents, DPPH, and FRAP activities in the GSS extract powder. This study contributed to the body of knowledge by explaining the preparation of procyanidin extract powder from GSS, which might be employed as a low-cost supply of nutraceutical compounds for the functional food industry and pharmaceutical sector