Yeast Extract Concentration Research Articles

상황버섯 자실체 추출물의 젖산발효를 통한 고농도 γ-aminobutyric acid 생산

The optimal production of γ-aminobutylic acid (GABA) has been accomplished using the extract of Phellinus linteus fruiting body (PLF) and Lactobacillus plantarum KS2020. To optimize the production of GABA through lactic acid fermentation, the medium composition was optimized for the concentration of glucose, monosodium glutamate (MSG), and yeast extract. The solid content, pH, acidity of PLF extract was 1.37%, 5.85, and 0.03%, respectively. The content of the minerals Ca, Mg, K, Na, P, Fe, and Mn in the PLF extract were 3.65, 2.07, 1.95, 1.43, 0.88, 0.05, and 0.01 mg per 100 g, respectively. In case of single lactic acid fermentation with the PLF extract including 5% MSG as a precursor and 1.5% yeast extract, the pH and acidity of the fermented PLF extract were 5.96, and 0.25%, respectively, and the viable cell count was 8.56 log CFU/mL. After 9 days of stationary fermentation, MSG was converted to highly concentrated GABA. High performance liquid chromatography (HPLC) analysis revealed that, the initial content of GABA (21.18 mg/100 g) increased to 2,412.34 mg/100 g in the fermented PLF extract. In conclusion, the fermented PLF extract using L. plantarum KS2020 and MSG as a precursor can be used for the production of high-value functional food ingredients, such as GABA and probiotics.

Fermentative production of 2,3-Butanediol using bread waste – A green approach for sustainable management of food waste

Bread is Europe’s most wasted food, and the second most wasted food after potatoes in UK. Bread waste (BW) is a clean source of high-quality fermentable sugars. In this study, the potential of Enterobacter ludwigii to accumulate 2,3-butanediol (BDO) from BW was evaluated. Initially, the optimal inoculum size and yeast extract concentration were determined, followed by extraction of sugars from BW using acid and enzymatic hydrolysis. A glucose yield of 330–530 g/kg BW was obtained, and the sugars released were utilised for BDO production by E. ludwigii. The fed-batch cultivation using pure glucose and glucose rich hydrolysates from acid and enzymatic hydrolysis resulted in BDO titres of 144.5, 135.4, and 138.8 g/L, after 96 h, with yield of 0.47, 0.42 and 0.48 g/g yield, respectively. The innovation of the work is valorisation of BW to BDO with a circular biorefining approach and thus, reducing BW disposal and associated environmental burden.

"CELLULASE PRODUCTION OPTIMIZATION BY BACILLUS AERIUS THROUGH RESPONSE SURFACE METHODOLOGY IN SUBMERGED FERMENTATION "

The objective of the present study was to get better production of FPase from Bacillus aerius (MG597041) by optimizing different process parameters under submerged fermentation through the statistical approach. Optimization of physical factors of culturing medium by one factor at a time (OFAT) revealed optimum incubation time of 24 h, inoculum size of 1%, pH 5.5, and substrate concentration of 4%. Plackett-Burman design (PBD) was performed to identify the significant nutritional influence of cellulase production. Among the nine parameters screened, peptone, yeast extract, FeSO4 and K2HPO4 were found significant. CCD of significant parameters revealed maximum FPase activity (127.4 IU/mL/min) at the optimum concentration of yeast extract of 0.5 g/L, peptone of 0.5 g/L, FeSO4 of 0.2 g/L, and K2HPO4 of 0.02 g/L. ANOVA was used to analyze these results. The analysis of the results showed an F-value of 8.74 and a p-value 0.00. Maximum hydrolysis of 10% of raw Bombax ceiba seed pods using this indigenous cellulase was obtained after 24 h. Also, the study explored the potential of the obtained cellulase to be applied in denim biostoning finishing. The findings demonstrated the efficient use of the obtained enzyme in saccharification of raw Bombax ceiba seed pods, which can be of interest for production of biofuel, and in biostoning treatment of denim fabrics.

Production and optimization of l-asparaginase by Streptomyces koyangensis SK4 isolated from Arctic sediment.

Actinomycetes isolated from the Arctic sediment were evaluated for the production of the enzyme l-asparaginase, an enzyme used to treat acute lymphoblastic leukemia. The most potent strain Streptomyces koyangensis SK4 was selected for l-asparaginase enzyme production by submerged fermentation. The effect of various fermentation parameters on enzyme production was analyzed statistically using the Plackett-Burman design and response surface method. Effects of eight parameters including temperature, pH, incubation time, inoculum size, agitation speed, the concentration of starch, l-asparagine, and yeast extract were studied on l-asparaginase production by the Arctic isolate S. koyangensis SK4. Factors such as temperature, pH, incubation time, agitation speed, and l-asparagine concentration were found to be important factors influencing l-asparaginase production. Maximum enzyme activity of 136 IU/ml was obtained at 20°C on the seventh day of incubation in the asparagine dextrose broth maintained at pH 7.5, agitation speed 125 rpm, and l-asparagine concentration of 7.5 g/L. The statistical optimization method described in this study proved effective for increasing the l-asparaginase production by Arctic actinomycetes.

Bioactivity study and metabolic profiling of Colletotrichum alatae LCS1, an endophyte of club moss Lycopodium clavatum L.

Endophytes are silent microbial partners of green plants that ensure hosts’ survival in odd conditions. They are known as the factories of multipotent metabolites with diverse bioactivities beneficial to modern pharmaceuticals industry. Endophytic fungi have been screened from a variety of plants and it is the first-time endophytes of club moss is being studied for production of antibacterial and antioxidative compounds. The present study reveals that Lycopodium clavatum L. harbors a potent niche of bioactive endophytic fungi and Colletotrichum alatae LCS1 was the prime producer of antibacterial and antioxidative compounds among them. The minimum inhibitory and bactericidal concentrations of ethyl- acetate culture extract ranged from 15.62 to 250 μg/mL against four Gram negative and three Gram positive microorganisms including methicillin resistant Staphylococcus aureus (ATCC-33591). Bio-autogram based screening followed by Gas chromatographic analysis confirmed the occurrence of 17 bioactive compounds and α-bisabolol is known to be the prime one. Alfa bisabolol is a unique and versatile bioactive essential oil and facilitates variety of functions. Killing kinetics data along with leakage of macromolecules into extracellular environment supports the cidal activity of the antibacterial principles at MBC values. Isolate C. alatae LCS1 was optimized by one variable at a time system coupled with response surface methodology for broad spectrum antibacterial production. The organism yielded maximum response (22.66±0.894 mm of zone of inhibition against MRSA) in 250 mL Erlenmeyer flask containing 50 mL potato dextrose broth supplemented with (g/L) glucose, 7.53; yeast extract concentration, 0.47; NaCl, 0.10 with medium pH 6.46; after 134 hours of incubation at 26°C. Optimized fermentation parameters enhanced antibacterial activity up-to more than 50% than the pre-optimized one (10.33±0.57 mm). Endophytic LCS1 was also efficient in free radical scavenging tested by DPPH, ABTS, H2O2 and FRAP assay with an IC50 values of 23.38±5.32 to 82.873±6.479 μg/mL.

Agarwood (Aquilaria malaccensis) diversity conservation by in vitro culture with IAA and yeast extract

Abstract. Samanhudi, Sakya AT, Setyawati A, Muawanah M. 2022. Agarwood (Aquilaria malaccensis) diversity conservation by in vitro culture with IAA and yeast extract. Biodiversitas 23: 2457-2463. Agarwood (Aquilaria malaccensis) is a scare plant with high economic value and many benefits. Tissue culture is an effective way of producing plants in large quantities, in a short time with uniform results. This study aims to get the proper concentration of IAA and yeast extract for agarwood growth in vitro. The research was conducted in December 2019-June 2020 at the Laboratory of Plant Physiology and Plant Biotechnology, Faculty of Agriculture, Universitas Sebelas Maret, Surakarta. The design used is Randomized Complete Block Design (RCBD) in 2 factors: first factor was IAA concentration with 4 level: 0; 0,5; 1; 1.5 mgL-1 and second factor was yeast extract concentration with 4 levels: 0; 200; 400; 800 mgL-1. Obtained 16 combinations of treatments repeated 3 times so that there are 48 units of experiments. Observed variables: the time of appearance of shoots, the number of shoots, the height of shoots, the number of leaves, and the number of roots. Root count data is described and data other than root count is analyzed ANOVA, if real influence is further tested DMRT 5%. The IAA affects the height of shoots and the number of agarwood leaves in vitro rooted plantlets has 5 plantlets.

Feather-Degrading Bacillus cereus HD1: Genomic Analysis and Its Optimization for Keratinase Production and Feather Degradation.

Keratinase is an important enzyme that is used to degrade feather wastes produced by poultry industries and slaughterhouses that accumulate rapidly over time. The search for keratinase-producing microorganisms is important to potentially substitute physicochemical treatments of feather waste. In this study, the genome of Bacillus cereus HD1 and its keratinolytic prowess was investigated. The whole-genome shotgun size is 5,668,864bp consisting of 6083 genes, 69 tRNAs, and 10 rRNAs. The genomic analyses revealed 15 potential keratinase genes and other enzymes that might assist keratin degradation, such as disulfide reductase and cysteine dioxygenase. The optimal conditions for feather degradation and keratinase production by B. cereus HD1 such as incubation time, pH, temperature, yeast extract, and glycerol concentrations were determined to be 5days, pH 8, 37°C, 0.05% (w/v), and 0.1% (v/v), respectively. Under optimized conditions, B. cereus HD1 exhibited feather degradation of 65%, with bacterial growth and maximum keratinase activity of 1.3 × 1011CFU/mL and 41U/mL, respectively, after 5days of incubation in a feather basal medium. The findings obtained from this study may facilitate further research into utilizing B. cereus HD1 as a prominent keratinolytic enzymes production host and warrant potential biotechnological applications.

Biodegradation of Azo Dye by Bacterial Species Isolated from Dye Contaminated Area of Jetpur, Gujarat

The varieties of synthetic azo dyes are widely used in textile industries to generate range of color tones in the textile and paper industries. Such textile dyes are toxic for the animals, birds and human along with environment. It is needful to remove those dyes from the effluent. The degradation of such dyes is accompanied by the involvement of dye degradating microorganisms. The purpose of this research is to isolate, identify, and screen bacterial species capable of decolorizing reactive pink, congo red, and malachite green. Soil and water samples were collected from the dye contaminated area of Jetpur, Gujarat, India. Dye degradating bacteria were isolated and selected through primary and secondary screening. The effect of yeast extract amount on the dye degradation properties of bacteria was examined using a visible spectrophotometer.
 After secondary screening MD2, MD8, MD20, MD31, MD33 and MD34 were selected for further analysis. All isolated are able to degrade reactive pink, congo red, and malachite green after 120hrs of incubation at a 4mgl-1 concentration of yeast extract. Dye degradation remains constant for 4 mgl-1 and 2 mgl-1 but gets reduced in 1 mgl-1 of yeast extract concentration. Wheat germination rate in control was 65% compared to 96%, 88%, and 85% in MD2, MD8, MD20 respectively. Sorghum germination rate in control was 62% while in isolates no MD31, MD33, MD34 were 96%, 87%, 83% and 65%.

Development of EPS-rich herbal shampoo base fermented using Cyclea peltata leaf powder and Lactobacillus plantarum.

Studies show that the extensive use of chemical shampoos has a negative impact on health. Given the recent trends, the use of herbal shampoos is gaining importance. Cyclea peltata is a common plant in Kerala's coastal region that has traditionally been used to aid in wound healing, allergy relief, and hair and scalp improvement. Greenly produced silver nanoparticles made from plant sources have a wide range of medical applications. The main objective is to optimize the base of the shampoo with better solid content by OFAT studies and characterize the silver nanoparticles synthesized using post optimized shampoo base. Cyclea peltata leaves were fermented with Lactobacillus plantarum for the shampoo formulation, substituting the chemical basis gelatin with an herbal fermented foundation. Silver nanoparticles combined with an herbal formulation should be as safe as herbal shampoo while also being as effective as chemical shampoo. Variation of concentration of Cyclea peltata leaf powder, variation of sucrose concentration, variation of concentration of yeast extract, variation of L.plantarum inoculum, variation of temperature, variation of agitation speed, and variation of time were all studied using the OFAT (One Factor At a Time) method. Silver nanoparticles synthesized using post optimized shampoo bases were also characterized by particle size, zeta potential, and FTIR analysis in order to better understand their properties. The results clearly indicated that all the six factors had a significant effect on the growth and production of EPS. The pH considered for the shampoo base is above 5so as to maintain the acidic mantle of the scalp. Green synthesized silver nanoparticles from post optimized shampoo base were obtained within 17th hour of incubation, with single surface plasmon resonance at 420nm. Nanoparticles showed a peak at -11.6mv of zeta potential which means that the particles are less agglomerative and stable. Similar groups were seen in ftir spectrum of fermented silver nanoparticles and the plant extract which confirmed the capping of nanoparticles with plant phytochemicals. The study successfully prepared and characterized green synthesized silver nanoparticles from post optimized shampoo base and also optimized the shampoo base based on the EPS production. Characterization of the silver nanoparticles found that the nanoparticles synthesized were stable, less agglomerative,and had several useful components present in it.

Optimization of Skim Milk Based Medium for Biomass Production of Probiotic Lactobacillus Acidophilus ATCC 4356 Using Face Central Composite Design-Response Surface Methodology Approach

The use of commercial media to support probiotic bacterial growth is limited by its cost and off-flavour generated in food products. Thus, this study optimized skim milk and yeast extract concentration as a cultivation medium for optimal Lactobacillus acidophilus ATCC 4356 biomasses using FCCD-RSM. The statistical analysis showed that the optimal compositions of skim milk and yeast extract were at 9.46 g/L and 1.07 g/L, respectively by setting the goal of optimization for biomass production to be at maximum level and the factor concentration in selected range. Besides, pH profiling showed pH value declined from 4.262 to 4.061 during cultivation due to organic acid produced from carbohydrate metabolism at the predicted response in optimal conditions (0.979 OD600) generated by the RSM tool. However, the experimental and predicted results were not significant difference (P>0.05) with low error percentage. As conclusion, the optimized skim milk (10g/L) and yeast extract (1g/L) obtained from RSM model and experimental values can be used to support better biomass production for L. acidophilus and prepare the cells for further application.

Yeast Extract Affecting the Transformation of Biogenic Tooeleite and Its Stability

Highly toxic As(III) is the main form of As in wastewater. The retention of As by tooeleite has gradually attracted attention in recent years due to its great potential for the direct removal of As(III). The existence of natural As-bearing minerals is closely related to microorganisms and organic matters. In this study, yeast extract was found to enhance the stability of biogenic tooeleite by Acidithiobacillus ferrooxidans (A. ferrooxidans). The effects of pH, Fe/As and yeast extract concentration were systematically studied, and the toxicity characteristic leaching procedure (TCLP) was conducted to evaluate the short-term stability of tooeleite. The mineral synthesized in the presence of yeast extract showed that the As leaching concentration decreased from 13.78 mg/L to 7.23 mg/L and the stability increased by more than 40%. In addition, various characteristics confirmed that the precursor was changed from amorphous schwertmannite to basic ferric sulfate in the presence of yeast extract, and then transformed to relatively purer tooeleite with less hollow structure and excellent dispersion, which is favorable for the stability of tooeleite. This result indicated that yeast extract resulted in the formation of different precursors and thus affected the transformation and stability of tooeleite.

Response surface methodology designation for optimization of lactic acid production by Streptococcus thermophilus isolated from industrial yogurt

Using inexpensive sources is a crucial point in the production of valuable compounds such as lactic acid. In the present study, the production of lactic acid by an efficient isolate of S. thermophilus was optimized using whey as a carbon source and yeast extract as a nitrogen source. MRS culture medium with 6.5 % NaCl was used for the isolation of streptococci from industrial yogurt samples and the selected isolate was identified using the 16S rRNA gene sequencing. Evaluation of lactic acid production was done by the Randox method. Lactic acid production by the selected isolate was optimized by response surface methodology (RSM) in MRS broth regarding to different concentrations of whey and yeast extract. The isolate that produced the highest amount (8.9 g.L-1) of lactic acid within 52 h growth in MRS broth was identified as a strain of S. thermophilus by molecular identification. Optimization of concentrations of carbon and nitrogen sources resulted in the induction of lactic acid production by Streptococcus thermophilus up to 24.18 g.L-1 in the presence of 3.5 % of whey and 5 % of yeast extract as external carbon and nitrogen sources in the MRS medium, which was similar to the value predicted by RSM. Yeast extract was found to be more effective on lactic acid production than whey. Optimization of lactic acid production by low-cost substrates whey and yeast extract resulted in high induction of lactic acid production by S. thermophilus compared to some other studies that used other cost-effective substrates and/or bacteria isolated from traditional dairy products.

Optimization of Lipid Production by Schizochytrium limacinum Biomass Modified with Ethyl Methane Sulfonate and Grown on Waste Glycerol.

One of the most promising avenues of biofuel research relates to using waste as a starting feedstock to produce liquid or gaseous energy carriers. The global production of waste glycerol by the refinery industry is rising year after year. The aim of the present study was to examine the effect of ethyl methane sulfonate (EMS) on the growth rates and intracellular lipid accumulation in heterotrophically-cultured Schizochytrium limacinum microalgae, grown on waste glycerol as the carbon source. The strain S. limacinum E20, produced by incubating a reference strain in EMS for 20 min, was found to perform the best in terms of producing biomass (0.054 gDW/dm3·h) and accumulating intracellular bio-oil (0.021 g/dm3·h). The selected parameters proved to be optimal for S. limacinum E20 biomass growth at the following values: temperature 27.3 °C, glycerol level 249.0 g/dm3, oxygen in the culture 26%, and yeast extract concentration 45.0 g/dm3. In turn, the optimal values for lipid production in an S. limacinum E20 culture were: temperature 24.2 °C, glycerol level 223.0 g/dm3, oxygen in the culture 10%, and yeast extract concentration 10.0 g/dm3. As the process conditions are different for biomass growth and for intracellular lipid accumulation, it is recommended to use a two-step culture process, which resulted in a lipid synthesis rate of 0.41 g/dm3·h.

Hydrolyzed feather keratin obtained by microbial fermentation encapsulated with maltodextrin – A sustainable approach to increase digestible protein in feed

Feathers are a bulky and problematic by-product of the poultry industry, consisting mainly of keratin that can be used as a protein source if appropriately hydrolyzed. The strain B4 successfully hydrolyzed feathers, reaching a maximum soluble protein concentration of 2.97 g/l with a productivity of 0.65 g/l/d in feather media previously standardized. After improving feather and yeast extract concentrations, the soluble protein increased to 9.26 g/l and the productivity to 1.53 g/l/d. The hydrolysate, showing peptides mass ranging from 500 to 1057 m/z, was microencapsulated with maltodextrin by spray-drying to produce powdered hydrolyzed feather (PHF). PHF had 11.4 g/100g of crude protein, 75.01 g/100g of starch, and 2.37% of moisture. The most abundant amino acids in PHF are leucine, valine, and glutamic acid, besides a high histidine and lysine concentration. Bacillus sp. B4 was also microencapsulated, and after 14 months, 80% of cells remained viable. This study describes a new biotechnological product based on microencapsulated feather hydrolysate. PHF was stable, soluble, with low moisture content, rich in amino acids, and maintained the viability of potential probiotic cells as Bacillus sp. B4, showing potential as a functional supplement for animal nutrition. • Feathers can be efficiently hydrolyzed by Bacillus sp. B4 in low mass peptides. • The hydrolysate was microencapsulated with maltodextrin to produce a powder (PHF). • PHF was rich in leucine, valine, glutamic acid, histidine, and lysine. • Bacillus sp. B4 was successfully microencapsulated with hydrolysate. • For the first time, feather hydrolysate was microencapsulated by spray-drying.

Isolation and characterization of halophilic strains from beef jerky

Beef jerky is a typically Brazilian food product that consists of adding salt (sodium chloride, NaCl) to bovine meat. Salt is used as main preservative when preparing jerked meat, however, certain species of microorganisms, known as halophiles, optimally develop in the presence of high salt concentrations, thus salty food may contain halophiles and cause undesirable alterations in the products. In this context, this study aims to isolate, characterize, and assess the growth parameters of halophilic strains isolated from beef jerky. Two halophilic strains were isolated: C11 strain, with cocci-shaped morphological features from white cream color, and V22 strain, with red pleomorphism. Both the lineages were gran-negative, catalase, and oxidase positive, with optimum growth time after 15 incubation days at 37 °C. The strains were neutrophilic, growing only at pH 7.0 and subjected to a 2x3 factorial experimental design to assess and optimize the growth of strains at different concentrations of NaCl, MgCl2, and yeast extract. We found that for both the optimal growth conditions, the studied variables ranged from 25 to 35 g L-1 of MgCl2, 5 g L-1 of yeast extract, but for NaCl, the C11 strain did not grow in medium containing 300 g L-1 (optimally at 200), while the V22 showed no growth in medium containing 100 g L-1 (optimally at 300). Therefore, the features of the isolates suggest that they belong to the Halobacteriaceae family.

The Potential of the Oil-Producing Oleaginous Yeast Rhodotorula mucilaginosa for Sustainable Production of Bio-Oil Energy

At the 2021 United Nations Climate Change Conference (COP26), many countries in the world agreed to reach the goal of net-zero greenhouse gas emissions by 2050. This issue constrains energy use, petrochemical use, and related manufacturing production patterns. It is undeniable that the diesel engine of large equipment is still widely used in engineering applications, and it will not disappear in a short time. Many industrial projects still have to face the use of diesel engines. This study was focused on the development of oil-producing microorganisms to generate lipids. The oleaginous yeast Rhodotorula mucilaginosa (R. mucilaginosa) was selected for liquid-state cultivation, and the conditions for growth of the yeast cells were assessed. For the liquid fermentation culture with a fixed inoculation amount of 5%, it was determined that a suitable oil-producing culture was obtained on the sixth day, and the optimum conditions involved a carbon source concentration of 60 g/L, a yeast extract concentration of 0.5 g/L, and a KH2PO4 concentration of 7.0 g/L for each batch of culture experiments. In addition, the extraction method and solvent for the extraction of R. mucilaginosa lipids were chosen. The acid-heat method using the green organic solvent ethyl acetate exhibited the best performance for extraction of yeast lipids under environmentally friendly and safe conditions. The analysis of lipids showed that the fatty acids obtained primarily contained C16:0, C18:1 and C18:2, and especially C18:1 (41%) lipids, indicating that R. mucilaginosa lipids are a good bio-oil source for the production of biodiesel.

Effect of Yeast Assimilable Nitrogen Content on Fermentation Kinetics, Wine Chemical Composition and Sensory Character in the Production of Assyrtiko Wines

Two wild-type Saccharomyces cerevisiae yeast strains (Sa and Sb) were tested for white wine production using Assyrtiko grape of Santorini. A third commercial Saccharomyces strain was also studied for comparison reasons. Two concentrations of yeast extract and diammonium phosphate (DAP) were added to the must (150 and 250 mg/L) in order to evaluate the effect of nitrogen content on the final wine quality. Analytical methods (HPLC, GC-MS) and sensory analysis were employed to assess the quality of the wines. Fermentation kinetics were monitored throughout the experiment. By the second day of fermentation, all strains showed an approximate consumption of 70% of amino acids. Differences among strains were observed regarding inorganic nitrogen requirements. Sb strain resulted in higher concentrations of higher alcohols (1.9-fold) and ketones (5.6-fold) and lower concentrations of esters (1.2-fold) compared to the control, while Sa strain resulted in higher content of fatty acids (2.1-fold). Both indigenous strains scored better results in aroma quality, body and acidity compared to control. The overall evaluation of the data highlights the great potential of the indigenous S. cerevisiae strains as fermentation starters providing promising results in the sector of terroir wines.

Bioprocessing of Agricultural Waste (Banana Pseudostem) by Solid-State Fermentation (SSF) for Production of Cellulase

Cellulase was produced by Cellulomonas uda utilizing banana stem waste by solid state fermentation (SSF). The different parameters effects considered like particle size of substrate, pH(incubation and extraction), incubation period, temperature (incubation and extraction), media components (yeast extract and peptone) and moisture of substrate on the production of cellulase was investigated. The optimum activity of cellulase produced by Cellulomonas uda on banana waste for particle size (6.97 IU/min for 1mm), extraction pH (7.13 IU/min for pH 7), incubation pH(6.97 IU/min for pH 7), extraction temperature (7.10 IU/min for 500C), incubation temperature (7.20 IU/min for 450C), incubation period (7.20 IU/min on 3rd day), moisture content (7.12 IU/min for 100% ), peptone content ( 7.23 IU/min for 0.5 gm) and yeast extract content (7.18 IU/min for 0.30gm) was recorded. The cellulase produced by Cellulomonas uda by using banana stem waste indicates the socio-econic utilization of agricultural waste. After purification and characterization; cellulase enzyme can be used in industrial processes.

Enhancing Saccharomyces cerevisiae Taxane Biosynthesis and Overcoming Nutritional Stress-Induced Pseudohyphal Growth.

The recent technological advancements in synthetic biology have demonstrated the extensive potential socio-economic benefits at laboratory scale. However, translations of such technologies to industrial scale fermentations remains a major bottleneck. The existence and lack of understanding of the major discrepancies in cultivation conditions between scales often leads to the selection of suboptimal bioprocessing conditions, crippling industrial scale productivity. In this study, strategic design of experiments approaches were coupled with state-of-the-art bioreactor tools to characterize and overcome nutritional stress for the enhanced production of precursors to the blockbuster chemotherapy drug, Taxol, in S. cerevisiae cell factories. The batch-to-batch variation in yeast extract composition was found to trigger nutritional stress at a mini-bioreactor scale, resulting in profound changes in cellular morphology and the inhibition of taxane production. The cells shifted from the typical budding morphology into striking pseudohyphal cells. Doubling initial yeast extract and peptone concentrations (2YP) delayed filamentous growth, and taxane accumulation improved to 108 mg/L. Through coupling a statistical definitive screening design approach with the state-of-the-art high-throughput micro-bioreactors, the total taxane titers were improved a further two-fold, compared to the 2YP culture, to 229 mg/L. Filamentous growth was absent in nutrient-limited microscale cultures, underlining the complex and multifactorial nature of yeast stress responses. Validation of the optimal microscale conditions in 1L bioreactors successfully alleviated nutritional stress and improved the titers to 387 mg/L. Production of the key Taxol precursor, T5αAc, was improved two-fold to 22 mg/L compared to previous maxima. The present study highlights the importance of following an interdisciplinary approach combining synthetic biology and bioprocessing technologies for effective process optimization and scale-up.

Optimization of dextran production from Leuconostoc strains isolated from different dairy products from Ouargla region Algeria

Leuconostoc (Ln) sp. belongs to a group of lactic acid bacteria, which has the capacity to produce dextran (an exopolysaccharides) in the presence of su-crose. dextran is industrially important, it was the first microbial exopolysac-charide affirmed for commercial use. This study aimed to optimize the pro-duction of the synthesized dextran by Ln strains species isolated from differ-ent dairy products. Morphological, cultural, physiological and biochemical characteristics were employed to identify 23 isolated strains. We have identi-fied the species: Ln. gelidum, Ln. carnosum, Ln. citreum, Ln. fallax, Ln. mesen-teroides subsp mesenteroides, Ln. mesenteroides subsp dextranicum, Ln. mesenteroides subsp cremoris. 20 strains had the capacity to produce dex-tran from sucrose. The precipitation and quantification of EPS on MRSs (Mark rogosa et sharpe sucrose) medium revealed a difference between the strains, by the total sugars assay method, the amount of EPS varied between 0.63 ± 0.19 and 2.41 ± 0.17 g / L of strains LnF70 and LnC1 (isolated from goat's milk), respectively. The dextran production from MRSs medium was better than from liquid MSE. The optimization of production on MRSs medi-um with different concentration of glucose, yeast extract and sucrose showed that the strains had good production with a concentration of 2% glucose, 0.3% yeast extract and 10% sucrose.