Recovery of yeast invertase from ethanol fermentation broth

Summary Ethanol fermentation broth produced by an aggregated form ofSaccharomyces uvarum strain contained invertase when sucrose-based raw materials were used. The amount of invertase in the borth was in the range of 1.4 to 4.8 units/ml, which was affected by the dilution rate, the concentration of corn steep liquor, and the type of sugar used. The activity of invertase in the broth could be maintained at 0.8 units/ml over two months. When the broth was passed through DEAE-cellulose beads and eluted with a NaCl-Tris-HCl buffer solution, a 75% recovery yield of invertase with 9-fold purification and 30-fold concentration could be achieved.     

戊糖乳杆菌发酵培养基氮源条件的优化

对戊糖乳杆菌发酵培养基的氮源条件进行了优化。通过单因素实验及响应面分析优化利用木糖高产乳酸的戊糖乳杆菌发酵培养基的不同氮源组合。优化得到的牛肉膏与柠檬酸氢二铵复合的最佳组成为牛肉膏17.72 g/L,柠檬酸氢二铵1.91 g/L,得到乳酸实际最大产量42.37 g/L。添加玉米浆与酵母粉和无机氮源复合的最佳组成为玉米浆46.54 g/L,酵母粉21.95 g/L,柠檬酸氢二铵9.95 g/L,可得到乳酸最大产量41.06 g/L。通过响应面优化减少了有机氮源的种类。牛肉膏与柠檬酸氢二铵的复合得到了更高的乳酸产量,且减少了有机氮源用量,节约了成本。玉米浆与酵母粉的复合解决了单一玉米浆造成的木糖利用速率过低的问题,同样得到较高浓度的乳酸。     

Propionic acid production by immobilized cells of a propionate-tolerant strain of Propionibacterium acidipropionici

Cells of the propionate-tolerant strain Propionibacterium acidipropionici P200910, immobilized in calcium alginate beads, were tested for propionic and acetic acid production both in a semidefined laboratory medium and in corn steep liquor in batch, fed-batch, and continuous fermentation. Cell density was about 9.8 × 10⁹ cells/g (wet weight) of beads, and beads were added to the medium at 0.1 g (wet weight) beads/ml. Beads could be reused for several consecutive batch fermentations; propionic acid production in the tenth cycle was about 50%–70% of that in the first cycle. In batch culture complete substrate consumption (glucose in semidefined medium, lactate in corn steep liquor) and maximum acid production were seen within 36 h, and acid yields from the substrate were higher than in free-cell fermentations. Fed-batch fermentations were incubated up to 250 h. Maximum propionic acid concentrations obtained were 45.6 g/l in corn steep liquor and 57 g/l in semidefined medium; this is the highest concentration achieved to date in our laboratory. Maximum acetic acid concentrations were 17 g/l and 12 g/l, respectively. In continuous fermentation of semidefined medium, dilution rates up to 0.31 h^–1 could be used, which gave higher volumetric productivities (0.96 g l^–1 h^–1 for propionic acid and 0.26 g l^–1 h^–1 for acetic acid) than we have obtained with free cells. Corn steep liquor shows promise as an inexpensive medium for production of both acids by immobilized cells of propionibacteria.Journal paper no. J- 15614 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project no. 3122     

Batch and repeated batch production of l(+)-lactic acid by Enterococcus faecalis RKY1 using wood hydrolyzate and corn steep liquor

Lactic acid production was investigated for batch and repeated batch cultures of Enterococcus faecalis RKY1, using wood hydrolyzate and corn steep liquor. When wood hydrolyzate (equivalent to 50 g l⁻¹ glucose) supplemented with 15–60 g l⁻¹ corn steep liquor was used as a raw material for fermentation, up to 48.6 g l⁻¹ of lactic acid was produced with, volumetric productivities ranging between 0.8 and 1.4 g l⁻¹ h⁻¹. When a medium containing wood hydrolyzate and 15 g l⁻¹ corn steep liquor was supplemented with 1.5 g l⁻¹ yeast extract, we observed 1.9-fold and 1.6-fold increases in lactic acid productivity and cell growth, respectively. In this case, the nitrogen source cost for producing 1 kg lactic acid can be reduced to 23% of that for fermentation from wood hydrolyzate using 15 g l⁻¹ yeast extract as a single nitrogen source. In addition, lactic acid productivity could be maximized by conducting a cell-recycle repeated batch culture of E. faecalis RKY1. The maximum productivity for this process was determined to be 4.0 g l⁻¹ h⁻¹.     

Acetate production byClostridium thermoaceticum in corn steep liquor media

A low-cost nutrient medium based on corn steep liquor (CSL) was developed for the production of acetates byClostridium thermoaceticum. Pre-treatment of CSL with dolime and vitamin supplementation increased the rate of acetate production. Adding excess nutrients in a fed-batch mode minimized by-product formation and increased final acetate concentration from 19 g L^–1 to 40 g L^–1 acetic acid. High yields of acetic acid (0.95 g g^–1 glucose in fed-batch mode) was probably due to the conversion of the lactic acid in CSL into acetic acid by the organism.     

Production of mycelial biomass and exo-polymer by <Emphasis Type="Italic">Hericium erinaceus</Emphasis> CZ-2: Optimization of nutrients levels using response surface methodology

The Doehlert experimental design was used to optimize the production of mycelial biomass and exopolymer from Hericium erinaceus CZ-2 in this study. Statistical analysis showed that the linear and quadric terms of 3 variables: corn flour, yeast extract, and corn steep liquor had significant effects. The optimized combination of these 3 variables was confirmed through validation experiments. The optimal conditions for higher production of mycelial biomass (19.92 g/L) were estimated when the media composition concentrations were set as: 30.85 g/L, corn flour; 2.81 g/L, yeast extract; 16.9 mL/L, corn steep liquor; 10 g/L, glucose; 1 g/L, KH₂PO₄; and 0.5 g/L, MgSO₄·7H₂O; while a maximal exo-polymer yield (1.653 g/L) could be achieved when setting concentrations of: 32.71 g/L, corn flour; 2.35 g/L, Yeast extract; 14.42 mL/L, Corn steep liquor; 10 g/L, glucose; 1 g/L, KH₂PO₄; and 0.5 g/L, MgSO₄·7H₂O. The upscale production was also investigated using a 15 L fermentor using the optimized medium.     

Effects of Corn Steep Liquor and Thiamine on l-Glutamic Acid Fermentation of Hydrocarbons: IV. Utilization of Hydrocarbons by Microorganisms

The effect of nutrients of natural source, such as corn steep liquor, peptone, and yeast extract, on the fermentative production of L-glutamic acid from hydrocarbons by a Corynebacterium was studied. Corn steep liquor and meat extract were found to be remarkably stimulatory to L-glutamic acid production; about 5 g per liter of L-glutamic acid were accumulated in a culture broth containing 3% n-paraffins, 0.01% corn steep liquor, and mineral salts. Among nutritional factors contained in corn steep liquor, biotin had very little effect on the accumulation of L-glutamic acid, but thiamine was highly stimulatory to L-glutamic acid production. The optimal concentration of thiamine for L-glutamic acid production was 3 to 5 μg per liter, and for cell growth, 50 μg per liter. L-Glutamic acid was accumulated in negligible quantity when the amount of thiamine in the culture broth was sufficient to support abundant growth of bacterial cells.     

Statistical evaluation and modeling of cheap substrate-based cultivation medium of Chlorella vulgaris to enhance microalgae lipid as new potential feedstock for biolubricant

Chlorella vulgaris (C. vulgaris) microalga was investigated as a new potential feedstock for the production of biodegradable lubricant. In order to enhance microalgae lipid for biolubricant production, mixotrophic growth of C. vulgaris was optimized using statistical analysis of Plackett–Burman (P-B) and response surface methodology (RSM). A cheap substrate-based medium of molasses and corn steep liquor (CSL) was used instead of expensive mineral salts to reduce the total cost of microalgae production. The effects of molasses and CSL concentration (cheap substrates) and light intensity on the growth of microalgae and their lipid content were analyzed and modeled. Designed models by RSM showed good compatibility with a 95% confidence level when compared to the cultivation system. According to the models, optimal cultivation conditions were obtained with biomass productivity of 0.123 g L^?1 day^?1 and lipid dry weight of 0.64 g L^?1 as 35% of dry weight of C. vulgaris. The extracted microalgae lipid presented useful fatty acid for biolubricant production with viscosities of 42.00 cSt at 40°C and 8.500 cSt at 100°C, viscosity index of 185, flash point of 185°C, and pour point of ?6°C. These properties showed that microalgae lipid could be used as potential feedstock for biolubricant production.     

A low-cost medium for mannitol production by Lactobacillus intermedius NRRL B-3693

The production of mannitol by Lactobacillus intermedius NNRL B-3693 using molasses as an inexpensive carbon source was evaluated. The bacterium produced mannitol (104 g/l) from molasses and fructose syrups (1:1; total sugars, 150 g/l; fructose:glucose 4:1) in 16 h. Several kinds of inexpensive organic and inorganic nitrogen sources and corn steep liquor were evaluated for their potential to replace more expensive nitrogen sources derived from Bacto-peptone and yeast extract. Soy peptone D (5 g/l) and corn steep liquor (50 g/l) were found to be suitable substitutes for Bacto-peptone (5 g/l) and Bacto-yeast extract (5 g/l), respectively. The bacterium produced 105 g mannitol per liter from the molasses and fructose syrup (1:1, total sugars 150 g/l; fructose:glucose 4:1) in 22 h using a combination of soy peptone D (5 g/l) and corn steep liquor (50 g/l). This is the first report on the production of mannitol by fermentation using molasses and corn steep liquor.Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.     

Optimization of Xylanase Production by Thermomyces Lanuginosus in Tomato Seed Meal Using Response Surface Methodology

Summary A 3² central composite experimental design was performed with the aim of optimizing xylanase production by Thermomyces lanuginosus grown on corn cobs in submerged cultures. Xylanase production was first tested on different nitrogen sources (tomato skin, tomato seed meal, corn steep liquor, meat peptone, bacto-tryptone and yeast extract). Tomato seed meal was the selected substrate to test the effect of two variables on xylanase production (corn cobs and tomato seed meal concentrations). A second-order quadratic model and a response surface method showed that the optimum condition for xylanase production was corn cobs 4.6% (w/v) and tomato seed meal 2.1% (w/v). The optimum conditions found were transferred to 7-l bioreactors, where activities as high as 1630 U/ml were obtained.     

Optimization of medium composition for improving biomass production of Lactobacillus plantarum Pi06 using the Taguchi array design and the Box-Behnken method

An immune-enhancing strain, Lactobacillus plantarum Pi06, isolated from a healthy infant was used for biomass production following optimization of the medium in shake-flask culture. Preliminary studies showed that commercial MRS medium and cultivation under static conditions generated higher biomass production than four other tested media with or without a shaking condition. The selected medium composition, consisting of glucose, yeast extract, soy peptone, ammonium citrate, and corn steep liquor, was further optimized using a systematic method that integrated the Taguchi array design and the Box-Behnken method. The response effects of these factors were first investigated using Taguchi design under an L ₁₆ (4⁵) array. The suggested medium composition, derived from Statistica 7.1 using the Taguchi design, was applied to cultivate cells and a biomass of 7.16 g dry cell weight (DCW)/L was obtained. Response surface methodology based on the Box-Behnken method for the three response variables of glucose, yeast extract, and corn steep liquor was then used to further increase the biomass level to 8.94 g DCW/L. The resulting optimum medium consisted of 35 g/L glucose, 35 g/L yeast extract, and 40 mL/L corn steep liquor. Compared with the initial medium, the biomass yield was improved from 4.31 to 8.94 g DCW/L, an enhancement of approximately 107%.     

Phenazine-1-carboxylic acid production in a chromosomally non-scar triple-deleted mutant Pseudomonas aeruginosa using statistical experimental designs to optimize yield

We constructed a non-scar triple-deleted mutant Pseudomonas aeruginosa to improve phenazine-1-carboxylic acid (PCA) yield and then optimized the culture conditions for PCA production. Using a non-scar deletion strategy, the 5′-untranslated region of the phz1 gene cluster and two genes, phzM and phzS, were knocked out of the P. aeruginosa strain M18 genome. The potential ability for high-yield PCA production in this triple-deleted mutant M18MSU1 was successfully realized by using statistical experimental designs. A 2^5–1 fractional factorial design was used to show that the three culture components of soybean meal, corn steep liquor and ethanol had the most significant effect on PCA production. Using a central composite design, the concentration of the three components was optimized. The maximum PCA production was predicted to be 4,725.1 mg/L. With the optimal medium containing soybean meal 74.25 g/L, corn steep liquor 13.01 g/L and ethanol 21.84 ml/L, a PCA production of 4,771.2 mg/L was obtained in the validation experiments, which was nearly twofold of that before optimization and tenfold of that in the wild-type strain. This non-scar triple-deleted mutant M18MSU1 may be a suitable strain for industrial production of this biologically synthesized fungicide due to its high PCA production, presumed safety, thermal adaptability and cost-effectiveness.     

Effect of nitrogen source on pullulan production by Aureobasidium pullulans grown in a batch bioreactor

Pullulan production by Aureobasidium pullulans ATCC 201253 using selected nitrogen sources was studied in a medium using corn syrup as a carbon source. Independent of the corn syrup concentration present, the use of corn steep liquor or hydrolysed soy protein as a nitrogen source instead of ammonium sulphate did not elevate polysaccharide production by ATCC 201253 cells grown in an aerated, batch bioreactor containing 4 litres of medium. Pullulan production on corn steep liquor or hydrolysed soy protein as a nitrogen source became more comparable as the concentration of corn syrup was increased. Cell weights after 7 days of growth on any of the nitrogen sources were similar. The viscosity of the polysaccharide on day 7 was highest for cells grown on ammonium sulphate and 12.5% corn syrup. The pullulan content of the polysaccharide elaborated by ammonium sulphate-grown cells on day 7 decreased as the corn syrup level rose in the medium while the pullulan content of polysaccharide produced by cells grown on corn steep liquor or soytone generally increased.     

Citric acid production by a novel Aspergillus niger isolate: II. Optimization of process parameters through statistical experimental designs

In this work, sequential optimization strategy, based on statistical designs, was employed to enhance the production of citric acid in submerged culture. For screening of fermentation medium composition significantly influencing citric acid production, the two-level Plackett-Burman design was used. Under our experimental conditions, beet molasses and corn steep liquor were found to be the major factors of the acid production. A near optimum medium formulation was obtained using this method with increased citric acid yield by five-folds. Response surface methodology (RSM) was adopted to acquire the best process conditions. In this respect, the three-level Box-Behnken design was applied. A polynomial model was created to correlate the relationship between the three variables (beet molasses, corn steep liquor and inoculum concentration) and citric acid yield. Estimated optimum composition for the production of citric acid is as follows pretreated beet molasses, 240.1g/l; corn steep liquor, 10.5g/l; and spores concentration, 10(8)spores/ml. The optimum citric acid yield was 87.81% which is 14 times than the basal medium. The five level central composite design was used for outlining the optimum values of the fermentation factors initial pH, aeration rate and temperature on citric acid production. Estimated optimum values for the production of citric acid are as follows initial pH 4.0; aeration rate, 6500ml/min and fermentation temperature, 31.5 degrees C.     

Optimization of polyhydroxybutyrate production by <Emphasis Type="Italic">Bacillus</Emphasis> sp. CFR 256 with corn steep liquor as a nitrogen source

Polyhydroxyalkanotes (PHAs), the eco-friendly biopolymers produced by many bacteria, are gaining importance in curtailing the environmental pollution by replacing the non-biodegradable plastics derived from petroleum. The present study was carried out to economize the polyhydroxybutyrate (PHB) production by optimizing the fermentation medium using corn steep liquor (CSL), a by-product of starch processing industry, as a cheap nitrogen source, by Bacillus sp. CFR 256. Response surface methodology (RSM) was used to optimize the fermentation medium using the variables such as corn steep liquor (5–25 g l⁻¹), Na₂HPO₄ 2H₂O (2.2–6.2 g l⁻¹), KH₂PO₄ (0.5–2.5 g l⁻¹), sucrose (5–55 g l⁻¹) and inoculum concentration (1–25 ml l⁻¹). Central composite rotatable design (CCRD) experiments were carried out to study the complex interactions of the variables. The optimum conditions for maximum PHB production were (g l⁻¹): CSL-25, Na₂HPO₄ 2H₂O-2.2, KH₂PO₄ − 0.5, sucrose − 55 and inoculum − 10 (ml l⁻¹). After 72 h of fermentation, the amount of PHA produced was 8.20 g l⁻¹ (51.20% of dry cell biomass). It is the first report on optimization of fermentation medium using CSL as a nitrogen source, for PHB production by Bacillus sp.     

Effect of Corn Steep Liquor on Mycelial Growth and Aflatoxin Production in Aspergillus parasiticus

Total aflatoxin concentrations produced by Aspergillus parasiticus, isolate 64-R8, in Czapek's broth fortified with corn steep liquor increased proportionately as the concentration of corn steep was increased from 0.5 to 8.0% (v/v) until maximal growth, as measured by dry mycelial weight, was reached. Thereafter, aflatoxin concentrations declined more rapidly than the rate of autolysis of mycelial material. Data are presented which indicate that the concentration of corn steep liquor also affects the ratio of production of aflatoxin B(1) and B(2) to that of aflatoxin G(1) and G(2). Further, this ratio also varies with time of incubation. Although both growth of the fungus and aflatoxin production are stimulated by the addition of corn steep to the basic medium, the stimulation of toxin production is much greater than fungus growth.     

Production of single cell protein using waste capsicum powder produced during capsanthin extraction

Aims: To produce single cell protein (SCP) by using waste capsicum powder produced during capsanthin extraction as a substrate. Methods and results: The extraction [CPM (capsicum powder medium)] from waste capsicum powder was used as culture medium to cultivate four yeast strains. The main composition of CPM was determined. The average concentration of total sugar, total nitrogen and phosphorous of CPM were 16·3, 3·7 g l^?1 and 785·4 mg l^?1, respectively. Four yeast strains were cultured in two CPMs, and the cell mass, protein content of cells and specific growth rate of cells were determined. Addition of corn steep liquor significantly increased the cell mass production. Presence of capsaicin in CPM did not show inhibition of cell growth of yeast tested. Conclusions: CPM contained sufficient nutrients and could be used as a good medium to produce SCP. Candida utilis 1769 was chosen as the biomass producer because of its highest SCP formation (6·8 g l^?1) and higher specific growth rate (0·12 h^?1). The amino acid composition of its protein was well balanced. Significance and Impact of the Study: Utilization of waste capsicum powder can reduce environmental pollution and increase protein supply for animal feed.     

Use of a sequential strategy of experimental design to optimize the inulinase production in a batch bioreactor

A potential application of inulinase in the food industry is the production of fructoligosaccharides (FOS) by the transfructosilation of sucrose. The FOSs present many interesting functional properties besides their ability to increase the shelf-life and flavor of many products. The use of an industrial medium represents a good alternative to producing inulinase at low cost, since the activity may improve, or at least remain the same, as that obtained using a synthetic medium. This work was an optimization study of the inulinase production by Kluyveromyces marxianus NRRL Y-7571 using industrial pre-treated culture medium in a bioreactor employing a sequential strategy of experimental design. Initially, a Plackett–Burman (Screening Design) design was used, where the studied variables were molasses, corn steep liquor, yeast extract concentration, and agitation and aeration rates. After the analysis of the effects, a central composite rotational design (CCRD) was carried out. The optimized condition for the inulinase production was: 250 g/l of molasses, 80 g/l of corn steep liquor, 6 g/l of yeast extract, 300 rpm of agitation and 1.5 vvm aeration rate, which resulted in an enzymatic activity of 1,317 ± 65 U/ml.     

Solid-state fermentation-supported enhanced production of α-galactosidase by a deoxyglucose-resistant mutant of <Emphasis Type="Italic">Aspergillus niger</Emphasis> and thermostabilization of the production process

The aim of the present investigation was to comparatively evaluate the behaviour of A. niger and its derepressed mutant in production of α-galactosidase in submerged (SmF) and solid state fermentation (SSF) using basal Vogel’s medium or corn steep liquor as nitrogen source and observe the response of latter source under both cultural techniques under different temperature regimes, and determine if SSF can be exploited in a wide range of temperature expected to vary in this fermentation system. All studies were performed in both systems under pre-optimized cultural conditions. Higher melting temperature and negative values of entropy of activation in SSF indicated that the genetic system of both organisms was thermodynamically resistant in the presence of corn steep liquor but sensitive to inactivation in the presence of Vogel’s nitrogen sources in submerged fermentation. This was reflected as the organisms demanded higher magnitudes of energy for product formation in the presence of ammonium salts. Studies on influence of corn steep liquor revealed that it had stabilizing effect too in both fermentation systems but the mutant strain was more stable in both fermentation systems. Because of these properties, the mutant organism may be exploited for bulk production of α-galactosidase in SSF under condition where temperature may fluctuate during fermentation.     

Production of Bakers' Yeast in Cheese Whey Ultrafiltrate

A process for the production of bakers' yeast in whey ultrafiltrate (WU) is described. Lactose in WU was converted to lactic acid and galactose by fermentation. Streptococcus thermophilus was selected for this purpose. Preculturing of S. thermophilus in skim milk considerably reduced its lag. Lactic fermentation in 2.3×-concentrated WU was delayed compared with that in unconcentrated whey, and fermentation could not be completed within 60 h. The growth rate of bakers' yeast in fermented WU differed among strains. The rate of galactose utilization was similar for all strains, but differences in lactic acid utilization occurred. Optimal pH ranges for galactose and lactic acid utilization were 5.5 to 6.0 and 5.0 to 5.5, respectively. The addition of 4 g of corn steep liquor per liter to fermented WU increased cell yields. Two sources of nitrogen were available for growth of Saccharomyces cerevisiae: amino acids (corn steep liquor) and ammonium (added during the lactic acid fermentation). Ammonium was mostly assimilated during growth on lactic acid. This process could permit the substitution of molasses by WU for the industrial production of bakers' yeast.