Corn steep liquor as a nutritional source for biocementation and its impact on concrete structural properties

Microbial-induced carbonate precipitation (MICP) has a potential to improve the durability properties and remediate cracks in concrete. In the present study, the main emphasis is placed upon replacing the expensive laboratory nutrient broth (NB) with corn steep liquor (CSL), an industrial by-product, as an alternate nutrient medium during biocementation. The influence of organic nutrients (carbon and nitrogen content) of CSL and NB on the chemical and structural properties of concrete structures is studied. It has been observed that cement-setting properties were unaffected by CSL organic content, while NB medium influenced it. Carbon and nitrogen content in concrete structures was significantly lower in CSL-treated specimens than in NB-treated specimens. Decreased permeability and increased compressive strength were reported when NB is replaced with CSL in bacteria-treated specimens. The present study results suggest that CSL can be used as a replacement growth medium for MICP technology at commercial scale.     

Improvement of glycerol production by Candida krusei in batch and continuous cultures using corn steep liquor

No fermentation parameter was affected at phosphate concentration above 0.4 g l^–1 when KH₂PO₄ was used as phosphate source and the glucose consumption rate was difficult to control when corn steep liquor (CSL) was adopted as the phosphate source. However, if CSL was supplemented as a source of growth factors instead of as the phosphate source, not only glucose uptake and glycerol was improved, but also fermentation became easy to control and a steady state of continuous culture was easily obtained.     

Decrease in Hydraulic Conductivity of a Paddy Field using Biocalcification in situ

The hydraulic conductivity of a paddy field (Anthraquic Dystrustept), a silty clay soil containing more than 29% (w/w) of gravel, in Nagoya University Farm was reduced by in situ treatment of subsurface soil using bentonite and biocalcification (microbial calcium carbonate precipitation) through the addition of CaCl₂, urea, and corn steep liquor (CSL). The treatment decreased the hydraulic conductivity of the field from an average of 10^?3 cm/s to a range of 10^?5 to 10^?7 cm/s during 69 days, with reducing the proportion of pores of subsurface soil larger than 75 µm in diameter. The biocalcification effect was observed at 10-cm thickness from the treated subsurface. Laboratory soil core experiments demonstrated that the decrease in the hydraulic conductivity was not attributed to the effect of bentonite but mainly to the effect of biocalcification. The addition of CSL enhanced the urease activity of soil required for biocalcification, even at 4°C, as indicated by a decrease in urease activation energy temperature sensitivity. These experimental results agreed with the gradual decrease in hydraulic conductivity observed in the field when the average daily temperature was 7°C (days 24–69). It was suggested that the biocalcification is a potential technique to reduce the hydraulic conductivity of paddy field.     

Kinetic Modeling and Error Analysis for Decontamination of Different Petroleum Hydrocarbon Components in Biostimulation of Oily Soil Microcosm

A microcosm study was constructed to investigate the effect of complex co-substrate (corn steep liquor, CSL) addition on indigenous bacterial community, rate and extent of petroleum hydrocarbons (PH) degradation in an oily soil with total petroleum hydrocarbons (TPH) content of 63353 mg kg^?1. TPH degradation was found to be characterized by a rapid phase of degradation during the first three weeks where 76% removal of TPH occurred, followed by a slower degradation phase, where further 7% of the initial TPH was removed by the end of incubation period, 35 d. Branched alkanes are more resistant to microbial degradation than n-alkanes. Furthermore, the unresolved complex mixtures (UCM) of hydrocarbons are less degradable than n- and iso-alkanes. Pristane (Pr) was the most recalcitrant aliphatic compound studied in this work. These results in addition to the extensive bacterial growth observed (from 10⁷ to 10¹⁰ CFU g^?1 soil) give strong support that the addition of CSL resulted in increased degradation rates. The indigenous bacteria grew exponentially during the incubation period of 35 d with a growth rate of 0.26 d^?1. Kinetic modeling was performed to estimate the rates of biodegradation of each hydrocarbon type component in the studied system. Five different error functions were used in this study to evaluate the fitness of the model equation to the obtained experimental data. This showed that the degradation of ∑nC₂₀-nC_24, ∑nC₃₅-nC₄₂ and nC₁₈ can be better represented by a second order model, whereas the TPH, total resolvable peaks (TRP), nC₁₇, UCM, ∑nC₁₀-nC₁₄, ∑nC₁₅-nC_19, ∑nC₂₅-nC₂₉, ∑nC₃₀-nC_34, ∑nC_n, and ∑isoC_n and isoprenoids Pr and phytane (Ph) were similarly following the first order model.     

Fermentative production of succinic acid from glucose and corn steep liquor byAnaerobiospirillum succiniciproducens

Anaerobiospirillum succiniciproducens requires expensive complex nitrogen sources such as yeast extract and polypeptone for its growth and succinic acid production. It was found thatA. succiniciproducens was able to grow in a minimal medium containing glucose when supplemented with corn steep liquor (CSL) as the sole complex nitrogen source. The concentration of CSL had a significant effect on the glucose consumption byA. succiniciproducens. When 10–15 g/L of CSL was supplemented, cells were grown to an OD₆₆₀ of 3.5 and produced 17.8 g/L succinic acid with 20 g/L glucose. These results are similar to those obtained by supplementing yeast extract and polypeptone, thereby suggesting that succinic acid can be produced more economically using glucose and CSL.     

The effect of corn steep liquor on the transformation of steroids

Summary As a nutrient in growth medium, corn steep liquor (CSL) may suppress 1-dehydrogenation of hydrocortisone 17-acetate byBacillus lentus, 11-hydroxylation of 6-fluoro-16-methyldeoxycorticosterone 21-acetate (FM-DOCA) byCurvularia lunata, and favor the formation of side-products. By means of step-down multiple regression analysis it was found that part of the variation in degree of steroid transformation in dependence on CSL quality can be explained by variable contents of SO₂, calcium and phosphorus for dehydrogenation and by ash, calcium, proline, and zinc for hydroxylation.     

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.     

An industrial medium for improved production of carotenoids from a mutant strain of Phaffia rhodozyma

A medium based on less expensive nutrient sources, such as corn starch hydrolyzate (hydrol), corn steep liquor (CSL), urea and potassium phosphate was used for the growth of the yeast Phaffia rhodozyma 2A2N strain. A central composite experimental design has been employed to derive a statistical model on the effect of hydrol and CSL on carotenoid production. An initial concentration of sugars as glucose equivalent 73?g/l in hydrol and 43?g/l CSL were found optimal for the maximization of final carotenoid production in shake flask cultures. The carotenoid production was increased by adding urea and phosphate sources. Laboratory scale fermentation was performed with the optimized medium and total carotenoid production of 52.4?mg/l was obtained using constant fed-batch culture.     

Effect of corn steep liquor on xanthan production by Xanthomonas campestris

Summary The addition of corn steep liquor (CSL) to batch cultures of Xanthomonas campestris using sucrose as carbon source stimulated cell growth rate, viscosity and xanthan production as compared to non-supplemented cultures. The addition of CSL to a basal medium at a dose of 1 g/l, increased xanthan production and viscosity by 22% and 44% respectively. CSL also shortened the cultivation time and promoted a more efficient sucrose utilization for polymer synthesis. After 72 h of incubation the xanthan yield per sucrose consumed in the CSL-amended culture was 0.63 g/g, this is, 15% higher than without CSL addition. At higher doses of CSL cell growth rate was also increased but not polymer production.     

Production of d-lactic acid by Lactobacillus delbrueckii ssp. delbrueckii from orange peel waste: techno-economical assessment of nitrogen sources

In this study, the effect of several organic nitrogen sources (namely peptone, meat extract—ME, yeast extract—YE, and corn steep liquor—CSL) on d-lactic acid production by Lactobacillus delbrueckii ssp. delbrueckii has been studied. While lactic acid bacteria (LAB) are well-known for their complex nutritional requirements, organic nitrogen source-related cost can be as high as 38% of total operational costs (OPEX), being its nature and concentration critical factors in the growth and productivity of the selected strain. Corn steep liquor (CSL) has been chosen for its adequacy, on the grounds of the d-lactic acid yield, productivity, and its cost per kilogram of product. Finally, orange peel waste hydrolysate supplemented with 37 g/l CSL has been employed for d-lactic acid production, reaching a final yield of 88% and a productivity of 2.35 g/l h. CSL cost has been estimated at 90.78$/ton of d-lactate.

     

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.     

Optimization of a corn steep medium for production of ethanol from synthesis gas fermentation by <Emphasis Type="Italic">Clostridium ragsdalei</Emphasis>

Fermentation of biomass derived synthesis gas to ethanol is a sustainable approach that can provide more usable energy and environmental benefits than food-based biofuels. The effects of various medium components on ethanol production by Clostridium ragsdalei utilizing syngas components (CO:CO₂) were investigated, and corn steep liquor (CSL) was used as an inexpensive nutrient source for ethanol production by C. ragsdalei. Elimination of Mg²⁺, NH₄ ⁺ and PO₄ ³⁻ decreased ethanol production from 38 to 3.7, 23 and 5.93 mM, respectively. Eliminating Na⁺, Ca²⁺, and K⁺ or increasing Ca²⁺, Mg²⁺, K⁺, NH₄ ⁺ and PO₄ ³⁻ concentrations had no effect on ethanol production. However, increased Na⁺ concentration (171 mM) inhibited growth and ethanol production. Yeast extract (0.5 g l⁻¹) and trace metals were necessary for growth of C. ragsdalei. CSL alone did not support growth and ethanol production. Nutrients limiting in CSL were trace metals, NH₄ ⁺ and reducing agent (Cys: cysteine sulfide). Supplementation of trace metals, NH₄ ⁺ and CyS to CSL (20 g l⁻¹, wet weight basis) yielded better growth and similar ethanol production as compared to control medium. Using 10 g l⁻¹, the nutritional limitation led to reduced ethanol production. Higher concentrations of CSL (50 and 100 g l⁻¹) were inhibitory for cell growth and ethanol production. The CSL could replace yeast extract, vitamins and minerals (excluding NH₄ ⁺). The optimized CSL medium produced 120 and 50 mM of ethanol and acetate, respectively. The CSL could provide as an inexpensive source of most of the nutrients required for the syngas fermentation, and thus could improve the economics of ethanol production from biomass derived synthesis gas by C. ragsdalei.     

Hyperproduction of N-acetylneuraminate lyase by the gene-cloned strain ofEscherichia coli

Summary Optimal culture medium for production ofN-acetylneuraminate lyase (NANA lyase) by the gene-cloned strain ofEscherichia coli, E. coli(pNALl), was screened to develop the process for the industrial production of NANA lyase. Out of nutrients tested, corn steep liquor (CSL) and sugarcane molasses were superior nutrient sources for the enzyme production. Hyperproduction (6–8 units/ml-broth) was achieved on the medium consisted of CSL and molasses.     

Fermentation of n-Paraffins by Yeast

Nutritional requirement of Candida lipolytica AJ 5004 and its productivity of α-ketoglutarate were further studied.

It became clear that this yeast required only thiamine as grown factor, and even if the yeast was cultured in chemically defined medium containing adequate amount of thiamine, it was able to produce as high yield of α-ketoglutarate as in the medium containing 0.02% of corn steep liquor.

It was also shown that the rate of convertion of n-paraffin to α-ketoglutarate gradually increased as the concentration of n-paraffins was decreased or as the incubation time was prolonged. A very high rate of conversion, 71%, was obtained after prolonged culture, for 5 days, with a culture medium containing 8% of n-paraffins.

The productivity of α-ketoglutarate from C₉- to C₂₀-alkanes by the yeast was maximum in the range from C₁₅ to C₁₉, especially from C₁₇ to C₁₉.     

Equilibrium oxygen concentration in fermentation fluids

Summary The equilibrium oxygen concentration (C₀) was determined in a complex fermentation media containing sucrose, lysine, molasses, corn steep liquor, antifoam agents and biomass. In simple systems, with all the components being dissolved, C₀ represents the oxygen solubility and linearly decreases with increasing solute concentrations. In complex solutions with multi-phase structure an increase in C₀ can be detected. It suggests that C₀ consists of two components — one being oxygen solubility, the other being determined by the amount of oxygen adsorbed on the interphase and bound by macromolecules. The presence of biomass leads to a decrease in C₀.     

Cost-effective optimization of gellan gum production by Sphingomonas paucimobilis using corn steep liquor

Abstract

Gellan gum, produced by Sphingomonas paucimobilis, is increasingly used in food and pharmaceutical industries as stabilizing, emulsifying, texturing and gelling agents. However, its high production costs may limit its full commercial potential. Therefore, in this study, we investigated ways to reduce gellan gum production costs and improve yields. We first revealed corn steep liquor (CSL) as a cost-effective nutrient source that can improve gellan gum yields. We then systematically optimized culture conditions even further, and revealed that the addition of Triton X-100 surfactant and selected inorganic nitrogen sources improved gellan gum production. Under our optimized conditions (glucose 33.75?g/L, CSL 10?g/L, urea 2.5?g/L, MgSO₄ 1.08?g/L, KH₂PO₄ 3.24?g/L, K₂SO₄ 1?g/L and Triton X-100 0.75?g/L), we yielded a maximum concentration of 14.41?g/L, which was about 1.5-fold higher than non-optimized CSL-based medium. Our findings highlight the use of CSL as a cost effective and promising nutrient source for industrial production of gellan gum.     

Influence of alkali-treated cornsteep liquor containing medium on protein A production byStaphylococcus aureus

Staphylococcus aureus cultivated in liquid media containing untreated cornsteep liquor (CSL) and alkali-treated CSL produced similar biomass yields (6.5–6.9 g/L). However, contents of protein A in the biomass was 0.5% and 1.56% for untreated CSL and treated CSL, respectively. Addition of treated CSL at 20 g/L achieved optimal enhancement of protein A production (0.11 g/L). Probable factors associated in treated CSL for the enhanced protein A production are discussed.     

A Low-Cost Fermentation Medium for Thermophilic Protease Production by Streptomyces sp. 594 Using Feather Meal and Corn Steep Liquor

Protease production by Streptomyces sp. 594 was obtained after submerged fermentation (SF) and solid-state fermentation (SSF) using feather meal (FM) and corn steep liquor (CSL) as sole sources of carbon and nitrogen. Enzyme productions were 13.4 U ml⁻¹ in SF and 21.5 U g⁻¹ in SSF; these values were approximately 86% and 39% higher, respectively, than those obtained previously when yeast extract was used in place of CSL. The proteases, which belong to the serine and metalloproteinase classes, were active at high temperatures (55°C to 90°C) and over a wide range of pH values (5.0 to 10.0). Thus, these thermophilic proteases have shown interesting properties for industrial purposes. As far as we are concerned, this is the first contribution toward the microbial production of thermophilic proteases by a streptomycete using a low-cost medium composed of industrial poultry (FM) and corn processing by-products (CSL).     

Batch and continuous cultures of<Emphasis Type="Italic"> Mannheimia succiniciproducens</Emphasis> MBEL55E for the production of succinic acid from whey and corn steep liquor

Mannheimia succiniciproducens MBEL55E isolated from bovine rumen is able to produce a large amount of succinic acid in a medium containing glucose, peptone, and yeast extract. In order to reduce the cost of the medium, whey and corn steep liquor (CSL) were used as substrates for the production of succinic acid by M. succiniciproducens MBEL55E. Anaerobic batch cultures of M. succiniciproducens MBEL55E in a whey-based medium containing CSL resulted in the production of succinic acid with a yield of 71% and productivity of 1.18 g/l/h, which are similar to those obtained in a whey-based medium containing yeast extract (72% and 1.21 g/l/h). Anaerobic continuous culture of M. succiniciproducens MBEL55E in a whey-based medium containing CSL resulted in a succinic acid yield of 69% and a succinic acid productivity as high as 3.90 g/l/h. These results show that succinic acid can be produced efficiently and economically by M. succiniciproducens MBEL55E from whey and CSL.     

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.