Yeast Inoculum Research Articles

Bioethanol from <em>Parthenium Hysterophorus</em> Substrate by <em>Saccharomyces cerevisiae</em>

This study was aimed to determine the efficient part of the Parthenium hysterophorus plant as a substrate for bioethanol production and optimize fermentation conditions to enhance the yield. When different parts of Parthenium hysterophorus such as stem, leaves, roots, inflorescence, and whole plant were used as the substrate with Saccharomyces cerevisiae, significantly higher quantities of bioethanol were produced with whole plant and leaves (1% V/V) than the other plant parts chosen. The entire plant was chosen as a substrate for bioethanol production to address its noxious weed status and simultaneously achieving economically efficient output, making its removal from agricultural land for economic gain. Fermentation conditions were optimized sequentially, changing one factor at a time while keeping other variables constant. The sequence of optimization is time of fermentation, amount of substrate, amount of yeast inoculum, pH of the media and the solution: air space ratio. The optimized fermentation time with the whole plant of Parthenium hysterophorus resulted in a 3 times higher ethanol yield on the 4th day of fermentation. When 12.5 g/100 mL amount of whole Parthenium hysterophorus plant substrate was used, the ethanol yield was significantly increased by 7.3 times, while using 5 g/100 mL of yeast inoculum resulted in a significantly higher yield. The pH of the media was optimized to 4.8, and the solution: air space ratio was optimized to 1:1.3 bioethanol output was significantly increased by 10 times. After optimizing all culture conditions, the bioethanol yield from the whole plant Parthenium hysterophorus substrate was significantly increased (10 times) than the non-optimized conditions.

Integrated enzymatic hydrolysis of crude red onion extract and yeast treatment for production and purification of short-chain inulin and inulin neoseries oligosaccharides

As has been confirmed in our previous study, red onion is a promising source of inulin-fructan, inulin neoseries fructan, and their fructooligosaccharides (FOSs). Short-chain FOSs (SCFOSs) are potential prebiotics as they provide many health promoting benefits. However, short-chain inulin neoseries oligosaccharides isolated from plants have scarcely been studied. After prebiotic production, a purification step is essential to produce a functional prebiotic. The aim of this study was to develop new processes of integrated enzymatic hydrolysis of crude red onion extract and yeast treatment for production and purification of SCFOSs. Endo-inulinase is a key enzyme for hydrolysis of crude red onion extract to produce SCFOSs, while Candida orthopsilosis FLA44.2 was employed for purification of the produced SCFOSs. Three different strategies, including two-step (TSP), simultaneous (SP), and semi-simultaneous (SSP) production processes, were designed and investigated as potentially simple, cost-effective, and timesaving production processes. The SP and SSP processes met the objective criteria by exhibiting desirable yields of SCFOSs and the optimal purity of SCFOSs when compared with the TSP process. Notably, the SP process was highlighted as it was simpler than the SSP process. Under optimal conditions (0.4 U of endo-inulinase/g total fructans, 5 % v/v of yeast inoculum and reaction time of 72 h), the SP process conducted in 1-dm3 flasks produced SCFOSs of 87 g/dm3 with neo-GF2 as the main constituent (42 g/dm3) and a purity of 100 %. The ratio of total SCFOSs to total fructans was 0.93 indicating that fructans of the red onion extract have been transformed to SCFOSs.

Quality improvement of soybean meal by simultaneous microbial fermentation and enzymolysis and untargeted metabolomic analysis of its metabolites

Twelve lactobacillus strains, four yeast strains, and eight proteases were screened, and their effects on oligosaccharide degradation, lactic acid production, and proteolytic capacity were investigated in soybean meal. The simultaneous microbial fermentation and enzymolysis (SMFE) conditions were optimized as feed/water ratio of 1:0.8 (w/v), yeast inoculum of 2.1×105 CFU/g, lactobacillus inoculum of 2.1×107 CFU/g, protease addition of 200 U/g, and fermentation at 37 °C for 48 h. The results showed that SMFE soybean meal exhibited superior performance over unprocessed soybean meal, showing increases in crude protein content from 49.8% to 56.3%, acid-soluble protein content from 3.7% to 10.4%, lactic acid production from 0 to 71.5 g/kg, and a decrease in oligosaccharide content from 6.4% to 0%. The comprehensive performance of SMFE soybean meal is higher than that from enzymolysis or fermentation alone Non-targeted metabolomic analysis revealed a diversity of metabolites in fermented soybean meal produced by different processes, and 8366 detected metabolites were mainly amino acids and their metabolites. Furthermore, among the six experimental groups, the metabolites of the SMFE group, and the yeast and lactic acid bacteria fermentation groups were the most similar. This study facilitates the assessment of overall quality of soybean meal and reveals the superiority of SMFE over traditional methods in enhancing nutritional profile of soybean meal.

Ultraviolet light C prototype device against Sporothrix brasiliensis as a potential physical method for surface disinfection.

Sporothrix brasiliensis is recognized as an emergent fungal pathogen and the high amount of fungal propagules in the lesions of infected cats allows the contamination of surfaces by direct contact. Given that the environment can play a role in the transmission of this fungus, effective methods to eliminate this pathogen from contaminated surfaces are necessary. Physical methods, such as ultraviolet light C (UVC), are broad used for surfaces disinfection, however, non-data about its activity against S. brasiliensis is reported. Therefore, we aimed to evaluate an easy handled prototype of a UVC device, in the inhibition of S. brasiliensis. Three doses and times of exposure of irradiance were tested: 3.5mJ/cm2 (1s), 5.25mJ/cm2 (1.5s) and 329mJ/cm2 (94s) against a standardized inoculum of yeast and mold phase of S. brasiliensis. A decrease in CFU was shown in all doses of irradiance in both phases of S. brasiliensis, the average reduction ranged from 78 to 100% among doses, being a complete fungicidal activity achieved against the yeast phase after the 94s exposure (329mJ/cm2). Our data shows that UVC is a potential physical method for disinfection of surfaces contaminated with S. brasiliensis, and the prototype device developed provides an easy handling, and quickly results.

Improvement of cell growth in green algae Chlamydomonas reinhardtii through co-cultivation with yeast Saccharomyces cerevisiae.

CO2 fixation methods using green algae have attracted considerable attention because they can be applied for the fixation of dilute CO2 in the atmosphere. However, green algae generally exhibit low CO2 fixation efficiency under atmospheric conditions. Therefore, it is a challenge to improve the CO2 fixation efficiency of green algae under atmospheric conditions. Co-cultivation of certain microalgae with heterotrophic microorganisms can increase the growth potential of microalgae under atmospheric conditions. The objective of this study was to determine the culture conditions under which the growth potential of green algae Chlamydomonas reinhardtii is enhanced by co-culturing with the yeast Saccharomyces cerevisiae, and to identify the cause of the enhanced growth potential. When C. reinhardtii and S. cerevisiae were co-cultured with an initial green algae to yeast inoculum ratio of 1:3, the cell concentration of C. reinhardtii reached 133 × 105cells/mL on day 18 of culture, which was 1.5 times higher than that of the monoculture. Transcriptome analysis revealed that the expression levels of 363 green algae and 815 yeast genes were altered through co-cultivation. These included genes responsible for ammonium transport and CO2 enrichment mechanism in green algae and the genes responsible for glycolysis and stress responses in yeast. We successfully increased C. reinhardtiigrowth potential by co-culturing it with S. cerevisiae. The main reasons for this are likely to be an increase in inorganic nitrogen available to green algae via yeast metabolism and an increase in energy available for green algae growth instead of CO2 enrichment.

Improving the Taste of Robusta Coffee by Fermentation with Yeast Inoculum and Its Effect on Caffeine Content

Harvesting coffee process by farmers generally executed entirety, resulting rainbow harvest. Coffee fermentation with yeast starter cultures Saccharomyces cerevisiae Y612, Candida parapsilosis Y207 and Torulospora delbrueckii Y594 was executed separately to determine the role of starter cultures on caffeine and robusta coffee taste at different maturity levels. The study was conducted at the Indonesian Industrial and Beverage Crops Research Institute in Sukabumi,, from June to November 2022. The experiment used a factorial complete randomized design. The first factor was the maturity level of the coffee and starter culture as the second factor. Fermentation was implemented for 48 hours inoculated with 108 cells/mL starter culture. The results showed that the temperature fluctuated, the pH value always decreased to 4.50 and T. delbrueckii was the starter culture with the highest activity during fermentation. Inoculum-fermented robusta coffee caffeine content was higher than non-inoculum. The lowest caffeine content was found in spontaneously fermented red fruit of 1.39%, while the highest caffeine content was produced by red fruit samples inoculated with C. parapsilosis of 2.7%. Robusta coffee with S. cerevisiae inoculation brought the best taste of robusta coffee with 82.10%, there was no significant difference between the red harvest coffee fruit and the fermented rainbow color with a starter culture. Keywords: Caffeine, Harvest, Inoculation, Maturity level, Starter cultures

Utilization of pretreated oil palm empty fruit bunches and their hydrolysate for ethanol production by Indonesian ethanologenic yeast

Abstract. Anita SH, Oktaviani M, Hermiati E. 2023. Utilization of pretreated oil palm empty fruit bunches and their hydrolysate for ethanol production by Indonesian ethanologenic yeast. Biodiversitas 24: 5243-5252. Oil Palm Empty Fruit Bunches (OPEFB) represent a polysaccharide-rich raw material with promising potential for ethanol production. This study aimed to investigate the ethanologenic yeasts, specifically Saccharomyces cerevisiae InaCC Y93 and Kluyveromyces marxianus InaCC Y119, affect bioethanol production in three different systems: Separate Hydrolysis and Fermentation (SHF), Simultaneous Saccharification and Fermentation (SSF), and Prehydrolysis-Simultaneous Saccharification and Fermentation (PSSF). This work is distinguished by the use of indigenous Indonesian yeast strains, including a thermotolerant strain. In the pretreatment process, 1.13% oxalic acid was added to OPEFB and subjected to microwave treatment at 190°C for 3.01 min. Subsequently, cellulase enzymes (40 FPU/g) and a 10% (w/v) yeast inoculum were introduced into 5.27 g dry weight of pretreated OPEFB pulp. The OPEFB acid hydrolysate was also subjected to fermentation. Ethanol content was monitored at 24 h intervals for 72 h. The PSSF system employs K. marxianus InaCC Y119 at 48 h exhibited the highest ethanol concentration, yielding 0.290 g/g, equivalent to approximately 51.20% of the theoretical yield. Additionally, K. marxianus InaCC Y119 demonstrated its capability to ferment the OPEFB acid hydrolysate into ethanol. These findings underscore the considerable potential of K. marxianus for applications in fermenting both hexose and pentose sugars to produce ethanol within higher-temperature systems.

Biological Control of Aspergillus parasiticus and Aspergillus ochraceus and Reductions in the Amount of Ochratoxin A and Aflatoxins in Bread by Selected Non-Conventional Yeast.

Aspergillus parasiticus and Aspergillus ochraceus are important pathogenic fungi that pose a serious threat because of their ability to produce mycotoxins, including ochratoxin A (OTA) and aflatoxins (AFs). The main method of reducing these pathogens is the use of chemical fungicides, though recently there has been a focus on finding biological control agents. The obtained results from this study indicate the great potential of two wild yeast strains, Aureobasidium pullulans PP3 and Saitozyma podzolicus D10, in the biological control of A. parasiticus and A. ochraceus and reductions in the amount of OTA and AFs they produce. In vitro, the growth of the mycelium of pathogens was reduced by 41.21% to 53.64%, and spore germination was inhibited by 58.39% to 71.22%. Both yeast strains produced the enzymes chitinase, β-1,3-glucanase, and amylase, and A. pullulans PP3 additionally produced protease and cellulase. This yeast strain also had the ability to grow over a wide range of temperature (4-30 °C), salinity (0-12%) and pH (4-11) conditions. No growth of the yeast was observed at 37 °C, nor any biogenic amines or hydrogen sulfide production. Adding the tested yeast inoculum to the dough reduced OTA (within 14.55-21.80%) and AFs (within 18.10-25.02%) in the model bread.

ВЛИЯНИЕ ВНЕШНИХ ФАКТОРОВ НА СВОЙСТВА ДРОЖЖЕЙ CANDIDA TROPICALIS ПРИ УТИЛИЗАЦИИ СПИРТОВОЙ БАРДЫ

To prevent environmental pollution from distillery waste, enterprises are required to carry out complete processing of stillage and / or dispose of it at treatment facilities, but it is not possible to fully utilize distillery stillage due to the lack of necessary strains of microorganisms. Therefore, in the processing of distillery stillage, the choice of a strain of microorganisms with sufficient biological activity is of particular relevance. For the first time, biotechnological utilization by the Candida tropicalis yeast strain AP-31-KBP Y-4883 was used for the processing of distillery stillage. Yeast activity was increased by two external factors: physical (UV radiation) and chemical (19-mycosaminyl nystatinolide) exposure. A rational concentration of 19-mycosaminyl-nystatinolide (500 U) was established at which Candida tropicalis colonies reached their maximum size. The efficiency of vinasse disposal was assessed by the accumulation of amine nitrogen in an aqueous solution after vinasse hydrolysis, the amount of which was determined by the formal titration method. Yeast inoculum, obtained after exposure to external factors, was introduced into a nutrient medium based on vinasse, and aerobic treatment was carried out for 72 hours. The morphological properties of cells and their number were controlled by optical and atomic force microscopy, the results of which are consistent with each other and with the biological activity of yeast. The greatest changes in the morphology of the cell surface are noted after chemical exposure: compared with the initial sample, the average cell height increased by 0.24 µm, and the surface area increased by 1.25 times. An increase in the degree of utilization of alcohol stillage by yeast was shown in the series “Candida tropicalis strain AP-31-KBP Y-4883 without treatment → UV-treated strain → antibiotic-treated strain”: indicators of biological activity increased by 4.3% (the proportion of cells saturated with glycogen ) and by 6.67% (amine nitrogen content); biomass yield increased by 1.7%. Increments of indicators are calculated in the transition from the original sample to the treated antibiotic. The assessment of the environmental hazard of bard samples was carried out using biotesting. It is shown that the efficiency of vinasse utilization increases after its treatment with yeast, which was previously exposed to UV radiation and an antibiotic. These samples were characterized by the highest germination of seeds relative to bards not treated with yeast.

Performance evaluation of a single-chamber microbial fuel cell with Zygosaccharomyces bailii

A microbial fuel cell (MFC) uses electroactive microorganisms, usually bacteria, to provide electrical energy while treating wastewater. The yeast-based MFCs are gaining relevance since yeasts present a higher ability to grow in harsh environments than most bacteria. Zygosaccharomyces bailii was used in an MFC to treat a synthetic winery wastewater, operating in sequential batch mod. The effect of yeast inoculum medium, pH, anodic conditions and the cathode current collector characteristics (configuration and material) on the system performance was evaluated, through polarisation measurements. A maximum power density of 1.34 ± 0.01 mW/m2 was achieved under anaerobic conditions, a synthetic winery wastewater with a pH of 7, and a cathode current collector made of titanium with an open ratio of 41 %. The wastewater treatment efficiency ranged between 27 % and 35 %. This study highlighted how alterations in the MFC characteristics can minimise these systems limitations, leading to improved performances. Moreover, the present work is an important step in yeast-based MFCs applied to wastewater treatment.

Transmission of beneficial yeasts accompanies offspring production in Drosophila-An initial evolutionary stage of insect maternal care through manipulation of microbial load?

Parent-to-offspring transmission of beneficial microorganisms is intimately interwoven with the evolution of social behaviors. Ancestral stages of complex sociality-microbe vectoring interrelationships may be characterized by high costs of intensive parental care and hence only a weak link between the transmission of microbial symbionts and offspring production. We investigate the relationship between yeast symbiont transmission and egg-laying, as well as some general factors thought to drive the "farming" of microscopic fungi by the fruit fly Drosophila melanogaster, an insect with no obvious parental care but which is highly dependent on dietary microbes during offspring development. The process of transmitting microbes involves flies ingesting microbes from their previous environment, storing and vectoring them, and finally depositing them to a new environment. This study revealed that fecal materials of adult flies play a significant role in this process, as they contain viable yeast cells that support larval development. During single patch visits, egg-laying female flies transmitted more yeast cells than non-egg-laying females, suggesting that dietary symbiont transmission is not random, but linked to offspring production. The crop, an extension of the foregut, was identified as an organ capable of storing viable yeast cells during travel between egg-laying sites. However, the amount of yeast in the crop reduced rapidly during periods of starvation. Although females starved for 24 h deposited a smaller amount of yeast than those starved for 6 h, the yeast inoculum produced still promoted the development of larval offspring. The results of these experiments suggest that female Drosophila fruit flies have the ability to store and regulate the transfer of microorganisms beneficial to their offspring via the shedding of fecal material. We argue that our observation may represent an initial evolutionary stage of maternal care through the manipulation of microbial load, from which more specialized feedbacks of sociality and microbe management may evolve.

Lactic acid bacteria and yeast strains isolated from fermented fish (Budu) identified as candidate ruminant probiotics based on in vitro rumen fermentation characteristics.

Probiotic supplementation can assist with manipulating the rumen microbial ecosystem. Lactic acid bacteria and yeast from fermented fish (Budu) as the indigenous food from West Sumatra, Indonesia, are potential probiotics for livestock. This study aims to select the best candidate lactic acid bacteria and yeast strains from fermented fish as ruminant probiotics and evaluate the effect of their supplementation on the characteristics of rumen fermentation, feed digestion, and total gas production in vitro. This study used nine treatments, performed in triplicate, in a completely randomized design. The substrate ratio comprised of 70% Pennisetum purpureum forage and 30% concentrate. Five lactic acid bacteria and three yeast isolates were used in this study. Treatments were as follows: T0: control (basal diet); T1: T0 + Lactobacillus parabuchneri strain 3347; T2: T0 + Lactobacillus buchneri strain 5296; T3: T0 + Lactobacillus harbinensis JCM 16178; T4: T0 + Schleiferilactobacillus harbinensis strain LH991; T5: T0 + L. parabuchneri strain 6902; T6: T0 + Pichia kudriavzevii strain B-5P; T7: T0 + P. kudriavzevii strain CBS 5147; and T8: T0 + commercial yeast (Saccharomyces cerevisiae). The lactic acid bacteria inoculum contained 1.02 × 1011 colony-forming unit (CFU)/mL, while the yeast inoculum contained 1.5 × 1010 CFU/mL. The results showed that four lactic acid bacteria and three yeast produced a higher total gas yield (104-183.33 mL) compared to the control (103 mL). Supplementation with lactic acid bacteria in the rumen fermentation in vitro showed dry matter digestibility of 63%-70% and organic matter digestibility (OMD) of 64%-71%. We observed that total volatile fatty acid (VFA) production in all treatments was significantly higher (86-121 mM) compared to the control (81 mM). The concentration of NH3 production was higher in all treatments (12.33-16.83 mM) than in the control (12.25 mM). Meanwhile, the probiotic supplementation did not cause a significant change in the rumen pH (6.86-7.12). Supplementation with the lactic acid bacteria S. harbinensis strain LH991 consistently demonstrated the best results from the parameters of dry and OMD (70.29% and 71.16%, respectively), total VFA (121.67 mM), NH3 (16.83 mM), and total gas production (149.17 mL). The best results were observed from the yeast candidate P. kudriavzevii strain B-5P, where the results were dry and OMD (67.64% and 69.55% respectively), total VFA (96.67 mM), NH3 (13.42 mM), and total gas production (183.33 mL). Based on the obtained results, lactic acid bacteria S. harbinensis strain LH991 and yeast P. kudriavzevii strain B-5P are attractive candidates to be utilized as probiotics for ruminants based on their potential to improve rumen fermentation in vitro. This probiotic supplementation can increase the digestibility of feed ingredients, production of total VFA and NH3, and total gas produced.

Wine Making: Influence of pH on Physicochemical Parameters of Wine Must Produce from Hot Water Extract of Broom-cluster Fig (Ficus capensis) Leaf using Saccharomyces cerevisiae

The chemical and biological stability of wine are very dependent on pH value, hence winemakers believe that pH plays a critical role in fermentation and final wine quality. This paper optimized and assessed the influence of pH on different physicochemical parameters of wine must prepared from hot water extract of the leaf of Broom-cluster Fig (Ficus capensis) leaf with Saccharomyces cerevisiae, ameliorating to 22 oBrix using table sugar and adding potassium metabisulfite. Then the pH of the must was adjusted as required and subjected to pasteurization. The must was inoculated with yeast inoculum at 0.8g/ml. Soluble solid, alcohol, titratable acidity and pH profile of the wine was monitored daily. After optimization and fermentation physicochemical parameters of the wine were analyzed. It was shown that pH of the must increase and decreased as the fermentation days progressed from day 1-12 for pH 3 -3.5 and 4-4.5 respectively. Total soluble solid decreased in all the must samples. The alcohol content increased gradually during fermentation. pH 3 and 4 had the highest titratable acidity when compared to pH 3.5 and 4.5. The pH of 4.5 wine had the lowest TSS and highest alcohol content. This study shows that wine can be produced from hot water extract of Ficus capensis leaf and the must fermented at lower pH gave highest percentage of alcohol. There is need to optimize and assess the pH of vegetable must before fermentation.

Reduction of Ethyl Carbamate in an Alcoholic Beverage by CRISPR/Cas9-Based Genome Editing of the Wild Yeast.

Ethyl carbamate (EC) is a naturally occurring substance in alcoholic beverages from the reaction of ethanol with urea during fermentation and storage. EC can cause dizziness and vomiting when consumed in small quantities and develop kidney cancer when consumed in excess. Thus, the reduction of EC formation in alcoholic beverages is important for food safety and human health. One of the strategies for reducing EC contents in alcoholic beverages is developing a new yeast starter strain to enable less formation of EC during fermentation. In this study, we isolated a polyploid wild-type yeast Saccharomyces cerevisiae strain from the Nuruk (Korean traditional grain-based inoculum of wild yeast and mold) and developed a starter culture by genome engineering to reduce EC contents in alcoholic beverages. We deleted multiple copies of the target genes involved in the EC formation in the S. cerevisiae by a CRISPR/Cas9-based genome editing tool. First, the CAR1 gene encoding for the arginase enzyme responsible for the formation of urea was completely deleted in the genome of S. cerevisiae. Additionally, the GZF3 gene encoding the transcription factor controlling expression levels of several genes (DUR1, 2, and DUR3) related to urea absorption and degradation was deleted in S. cerevisiae to further reduce the EC formation. The effects of gene deletion were validated by RT-qPCR to confirm changes in transcriptional levels of the EC-related genes. The resulting strain of S. cerevisiae carrying a double deletion of CAR1 and GZF3 genes successfully reduced the EC contents in the fermentation medium without significant changes in alcohol contents and fermentation profiles when compared to the wild-type strain. Finally, we brewed the Korean traditional rice wine Makgeolli using the double deletion strain of S. cerevisiae dCAR1&GZF3, resulting in a significant reduction of the EC content in Makgeolli up to 41.6% when compared to the wild-type strain. This study successfully demonstrated the development of a starter culture to reduce the EC formation in an alcoholic beverage by CRISPR/Cas9 genome editing of the wild yeast.

Phenolic-Degrading Enzymes: Effect on Haze Active Phenols and Chill Haze in India Pale Ale Beer.

The development of green and sustainable biotechnological approaches for preventing chill haze formation is currently under investigation. In this preliminary study, laccase and tannase (pure or combined) were applied as phenolic-degrading enzymes during two crucial brewing steps (i. post-mashing and ii. before the yeast inoculum). In post-mashing and irrespective of the dosage applied (100 μL/L or 1 mL/L), tannase-based treatment ensured the complete removal of haze active (HA) phenols, which was proved by the full prevention of chill haze (about 1 EBC vs. 22 EBC in the control sample). Before yeast inoculum for the alcoholic fermentation, the removal of haze active phenols and the prevention of chill haze were both tannase-dosage-dependent (15 and 2 EBC for the lowest and the highest dosages, respectively) although they failed to completely break down the HA phenols. This biotechnological approach did not significantly affect the chromatic properties of treated beer.

Utilizing rice straw and sugarcane bagasse as low-cost feedstocks towards sustainable production of succinic acid

Succinic acid (SA) has been produced from rice straw (RS) and sugarcane bagasse (SB) as low-cost feedstocks in this study through sequential peracetic acid (PA) and alkaline peroxide (AP) pretreatment assisted by ultrasound and pre-hydrolysis followed by simultaneous saccharification and fermentation (PSSF). The effect of yeast extract (YE) concentration, inoculum concentration, and biomass type on SA production was investigated. The results showed that SA production from RS and SB was significantly affected by the YE concentration. Final concentration and yield of SA produced were significantly increased along with the increasing of YE concentration. Moreover, inoculum concentration significantly affected the SA production from SB. Higher inoculum concentration led to higher SA production. On the other hand, SA production from RS was not significantly affected by the inoculum concentration. Using RS as the feedstock, the highest SA production was achieved on the medium containing 15 g/L YE with 5 % v/v inoculum, obtaining SA concentration and yield of 3.64 ± 0.1 g/L and 0.18 ± 0.05 g/g biomass, respectively. Meanwhile, the highest SA production from SB was acquired on the medium containing 10 g/L YE with 7.5 % v/v inoculum, resulting SA concentration and yield of 5.1 ± 0.1 g/L and 0.25 ± 0.05 g/g biomass, respectively. This study suggested that RS and SB are potential to be used as low-cost feedstocks for sustainable and environmentally friendly SA production through ultrasonic-assisted PA and AP pretreatment and PSSF.

Production of an ultrasound-assisted biosurfactant postbiotic from agro-industrial wastes and its activity against Newcastle virus.

The objective of this study is to optimize the biosurfactant production by Lactobacillus plantarum ATCC 8014 using low-cost substrates from industrial sources applying ultrasonication at 28 kHz frequency (power of 100 W). Given this, whey permeate and sugar cane molasses were screened to continue optimization using a central composite design to improve the production. Then, the effect of ultrasound was examined at different stages of microbial growth. The combination of whey permeate and sugar cane molasses with yeast extract (2.4 g/L) and inoculum size of 4.8% for 26 h of fermentation time significantly influenced biosurfactant production by reducing the surface tension of water (41.86 ± 0.24 mN/m). Moreover, ultrasonication led to the further reduction in surface tension value (39.95 ± 0.35 mN/m). Further, no significant differences were observed between products from synthetic and waste-based media. The biosurfactants exhibited antiviral activity against Newcastle disease virus (NDV) LaSota strain. It was discovered that biosurfactant produced in agro-food wastes with a significant antiviral effectiveness could be used to develop commercial application instead of chemical surfactants and biosurfactants from expensive synthetic media.

Cassava-based (Manihot esculenta Crantz) fermented energy-protein food for bovines

L Objective: To assess the effect of different yeast levels and fermentation times on the chemical, fermentative, and microbiological composition of cassava in order to produce a cassava-based fermented food. Design/Methodology/Approach: We used a completely randomized design with a factorial arrangement, three yeast inoculum levels (0, 5, and 10%), and five fermentation times (0, 1, 2, 3, and 4 days). Results: We found significant interaction of the studied factors with the pH and crude protein (CP) variables. The highest pH values were obtained adding 10% yeast inoculum (YI) (8.67). CP values of 16.55% were found. No differences caused by the studied inoculum levels and fermentation times were found in true protein (TP) and the in situ degradation of dry matter (IDDM). TP and IDDM had 8% and 80% values, respectively. Study Limitations/Implications: A behavior test with bovines must be conducted to demonstrate the potential of cassava-based fermented foods in meat and/or milk production. Findings/Conclusions: The yeast inoculum and the fermentation days did not increase the TP in the cassava-based fermented food.

A Minimally Invasive Approach for Preventing White Wine Protein Haze by Early Enzymatic Treatment.

Protein stability in bottled white wine is an essential organoleptic property considered by consumers. In this paper, the effectiveness of an early enzymatic treatment was investigated by adding a food-grade microbial protease at two different stages of winemaking: (i) at cold settling, for a short-term and low temperature (10 °C) action prior to alcoholic fermentation (AF); (ii) at yeast inoculum, for a long-lasting and medium temperature (18 °C) action during AF. The results reveal that protease sufficiently preserved its catalytic activity at both operational conditions: 10 °C (during cold settling) and 18 °C (during AF). Furthermore, protease addition (dosage 50–150 μL/L) raised the alcoholic fermentation rate. The treatment at yeast inoculum (dosage 50 μL/L) had a remarkable effect in preventing haze formation, as revealed by its impact on protein instability and haze-active proteins. This minimally invasive, time and resource-saving enzymatic treatment, integrated into the winemaking process, could produce stable white wine without affecting color quality and phenol content.

Bioethanol production from coconut fiber wastes using <em>Saccharomyces cerevisiae</em>

The principal energy source of the globe at present is non-renewable fossil fuels. With the arising of global dilemmas, the human population demands new energy sources. Coconut palm wastes have been identified as an important source of lignocellulosic biomass and it is underutilized in local industries, the accumulation of fiber has become a very problematic waste in Sri Lanka. Therefore, this study was aimed to determine the efficient coconut waste material for bioethanol production and to optimize the conditions for fermentation to enhance the yield. When the coconut husk fiber was inoculated with <em>Saccharomyces cerevisiae </em>(baker’s yeast 2g/L) in the fermentation media (100ml, 8o Brix, Waste extract: distilled water = 1:3) composed of 10 g/L yeast extract, 10 g/L KH₂PO₄, 2 g/L (NH₄)₂SO₄, 2g/L peptone and 0.5 g/L MgSO₄•7H₂O and allowed for fermentation for 24h at 30⁰C and 100rpm, the ethanol yield was 0.8% V/V. When different coconut palm wastes such as mature leaves (old leaves), young leaves (green leaves), young fruit fiber (kurumba), roots and husk fiber were used as the substrate with <em>Saccharomyces cerevisiae</em>, significantly higher quantities of bioethanol were produced with young leaves (green leaves) and husk fibers. However, coconut husk fiber was selected as a bioethanol source, for further studies due to its abundance and availability in the farms, slow natural degradation, and its role in providing a breeding ground for mosquitoes. The conditions were optimized sequentially by changing one factor at a time while keeping the other variables constant. When the fermentation time was optimized with coconut husk fiber the ethanol yield was significantly increased by 4 times at the 3rd day, than non-optimized conditions. When the amount of coconut husk fiber was increased by 2.5 times (12.5g/ 100 ml), bioethanol output was significantly increased by 6.4 times. Ethanol yield was significantly increased when 3.75g/ 100ml of yeast inoculum was used, compared to the non-optimized condition (1.25g/ 100ml). When the pH of the media was optimized as 4.8, significantly higher bioethanol yield was obtained, than the control (3.8). When the solution (V): air space (V) ratio was optimized to 1:1.3, bioethanol output was significantly increased by 6.6 times compared with the non-optimized condition (1:4). Large scale multi-centre fermentation study needs to be done in order to determine commercialization.