共查询到20条相似文献,搜索用时 31 毫秒
1.
A feeding technology that was suitable for improving the nisin production by Lactococcus lactis subsp. lactis W28 was established. The effects of initial sucrose concentration (ISC) in the fermentation broth, feeding time, and feeding
rate on the fermentation were studied. It was observed that a fed-batch culture (ISC = 10 g l−1) with 100 ml sucrose solution (190 g l−1) being evenly fed (9–10 ml h−1) into the fermenter after 3-h fermentation gave the best performance in terms of biomass and nisin yield. Under these conditions,
the total biomass and the total nisin yield were approximately 23% and 51% higher than those in batch fermentation, respectively.
When the sucrose concentration was controlled at 5–10 g l−1 in variable volume intermittent fed-batch fermentation (VVIF) with ISC = 10 g l−1, the total biomass and the total nisin yield were 29% and 60% above those in batch fermentation, respectively. The VVIF proved
to be effective to eliminate the substrate inhibition by maintaining sucrose at appropriate levels. It is also easy to be
scaled up, since various parameters involved in industrial production were taken into account. 相似文献
2.
The feasibility of using cull potatoes as substrate for the simultaneous production of nisin, a natural food preservative,
and lactic acid, a raw material for biopolymer production, was studied. Cull potatoes are potato tubers unacceptable for food
processing because ofsize or damage caused by bruising or disease. Although cull potatoes are enriched in various nutrients
including starch, minerals, and proteins, they alone still cannot provide enough essential nutrients for the growth and metabolism
of Lactococcus lactis subsp. lactis (ATCC 11454). Stimulation of bacterial growth, nisin biosynthesis, as well as lactic acid production was observed when additional
nutrients such as yeast extract, peptone from meat, peptone from soy (PS), corn steep solid (CSS), and distillers’ dried grains
with solubles were provided. Considering the cost and availability, PS and CSS were selected as nutrient supplements for nisin
and lactic acid coproduction. The conditions for nisin biosynthesis and lactic acid coproduction by L. lactis subsp. lactis in a cull potato-based medium were subsequently optimized using a statistically based experimental design. 相似文献
3.
Arachidonic acid (ARA) and eicosapentaenoic acid (EPA) were produced by Pythium irregulare fungus using soybean cotyledon fiber and soy skim, two co-products from soybean aqueous processing, as substrates in different fermentation systems. Parameters such as moisture content, substrate glucose addition, incubation time, and vegetable oil supplementation were found to be important in solid-state fermentation (SSF) of soybean fiber, which is to be used as animal feed with enriched long-chain polyunsaturated fatty acids (PUFA). Soybean fiber with 8 % (dwb) glucose supplementation for a 7-day SSF produced 1.3 mg of ARA and 1.6 mg of EPA in 1 g of dried substrate. When soy skim was used as substrate for submerged fermentation, total ARA yield of 125.7 mg/L and EPA yield of 92.4 mg/L were achieved with the supplementation of 7 % (w/v) soybean oil. This study demonstrates that the values of soybean fiber and soy skim co-products could be enhanced through the long-chain PUFA production by fermentation. 相似文献
4.
Chuanbin Liu Bo Hu Yan Liu Shulin Chen 《Applied biochemistry and biotechnology》1996,131(1-3):751-761
The production of nisin, a natural food preservative, by Lactococcus lactis subsp. lactis (ATCC 11454) is associated with the simultaneous formation of lactic acid during fermentation in a whey-based medium. As
a result of the low concentration and high separation cost of lactic acid, recovering lactic acid as a product may not be
economical, but its removal from the fermentation broth is important because the accumulation of lactic acid inhibits nisin
biosynthesis. In this study, lactic acid removal was accomplished by biological means. A mixed culture of L. lactis and Saccharomyces cerevisiae was established in order to stimulate the production of nisin via the in situ consumption of lactic acid by the yeast strain, which is capable of utilizing lactic acid as carbon source. The S. cerevisiae in the mixed culture did not compete with the nisin-producing bacteria because the yeast does not utilize lactose, the major
carbohydrate in whey for bacterial growth and nisin production. The results showed that lactic acid produced by the bacteria
was almost totally utilized by the yeast and the pH of the mixed culture could be maintained at around 6.0. Nisin production
by the mixed culture system reached 150.3 mg/L, which was 0.85 times higher than that by a pure culture of L. lactis. 相似文献
5.
The present work presents an alternative approach to ethanol production from sweet sorghum: without detoxification, acid-impregnated
fresh sweet sorghum stem which contains soluble (glucose and sucrose) and insoluble carbohydrates (cellulose and hemicellulose)
was steam pretreated under mild temperature of 100 °C. Simultaneous saccharification and fermentation experiments were performed
on the pretreated slurries using Saccharomyces cerevisiae. Experimentally, ground fresh sweet sorghum stem was combined with H2SO3 at dosages of 0.25, 0.50, and 0.75 g/g dry matter (DM) and steam pretreated by varying the residence time (60, 120, or 240 min).
According to enzymatic hydrolysis results and ethanol yields, H2SO3 was a powerful and mild acid for improving enzymatic digestibility of sorghum stem. At a solid loading of 10% (w/v) and acid dosage of 0.25 g/g DM H2SO3 at 100 °C for 120 min, 44.5 g/L ethanol was obtained after 48 ± 4 h of simultaneous saccharification and fermentation. This
corresponded to an overall ethanol yield of 110% of the theoretical one, based on the soluble carbohydrates in the fresh sweet
sorghum stem. The concentrations of hydroxymethylfurfural and furfural of the sulfurous acid pretreated samples were below
0.4 g/L. Ethanol would not inhibit the cellulase activity, at least under the concentration of 34 g/L. 相似文献
6.
D. A. Viana M. N. Carneiro-Cunha J. M. Araújo B. Barros-Neto J. L. Lima-Filho A. Converti A. Pessoa-Júnior A. L. F. Porto 《Applied biochemistry and biotechnology》2010,160(6):1797-1807
Clavulanic acid (CA) is a β-lactam antibiotic, which has a potent β-lactamase inhibiting activity. The influence of five variables,
namely pH (6.0, 6.4, and 6.8), temperature (28°C, 30°C, and 32°C), agitation intensity (150, 200, and 250 rpm), glycerol concentration
(5.0, 7.5, and 10 g/L) and soybean flour concentration (5.0, 12.5, and 20 g/L), on CA production by a new isolate of Streptomyces (DAUFPE 3060) was investigated in 250-mL Erlenmeyer flasks using a fractional factorial design. Temperature and soybean flour
concentration were shown to be the two variables that exerted the most important effects on the production of CA at 95% confidence
level. The highest CA concentration (494 mg/L) was obtained after 48 h at 150 rpm, 32°C, pH 6.0, 5.0 g/L glycerol, and 20 g/L
soybean flour concentrations. Under these conditions, the yields of biomass and product on consumed substrate were 0.26 gX/gS and 64.3 mgP/gS, respectively. Fermentations performed in 3.0-L bench-scale fermenter allowed increasing the CA production by about 60%. 相似文献
7.
Chuanbin Liu Yan Liu Wei Liao Zhiyou Wen Shulin Chen 《Applied biochemistry and biotechnology》2004,114(1-3):627-638
A biorefinery process that utilizes cheese whey as substrate to simultaneously produce nisin, a natural food preservative,
and lactic acid, a raw material for biopolymer production, was studied. The conditions for nisin biosynthesis and lactic acid
coproduction by Lactococcus lactis subsp. lactis (ATCC 11454) in a whey-based medium were optimized using statistically based experimental designs. A Plackett-Burman design
was applied to screen seven parameters for significant factors for the production of nisin and lactic acid. Nutrient supplements,
including yeast extract, MgSO4, and KH2PO4, were found to be the significant factors affecting nisin and lactic acid formation. As a follow-up, a central-composite
design was applied to optimize these factors. Second-order polynomial models were developed to quantify the relationship between
nisin and lactic acid production and the variables. The optimal values of these variables were also determined. Finally, a
verification experiment was performed to confirm the optimal values that were predicted by the models. The experimented results
agreed well with the model prediction, giving a similar production of 19.3 g/L of lactic acid and 92.9 mg/L of nisin. 相似文献
8.
Sugarcane bagasse and chicken manure were anaerobically fermented to carboxylic acids using a mixed culture of marine microorganisms
at 55 °C. Using the MixAlco process— an example of consolidated bioprocessing— the resulting carboxylate salts can be converted
to mixed alcohol fuels or gasoline. To enhance digestibility, sugarcane bagasse was lime pretreated with 0.1 g Ca(OH)2/g dry biomass at 100 °C for 2 h. Four-stage countercurrent fermentation of 80% sugarcane bagasse/20% chicken manure was performed
at various volatile solids (VS) loading rates and liquid residence times. Calcium carbonate was used as a buffer during fermentation.
The highest acid productivity of 0.79 g/(L day) occurred at a total acid concentration of 21.5 g/L. The highest conversion
(0.59 g VS digested/g VS fed) and yield (0.18 g total acids/g VS fed) occurred at a total acid concentration of 15.5 g/L.
The continuum particle distribution model (CPDM) predicted the experimental total acid concentrations and conversions at an
average error of 10.14% and 12.68%, respectively. CPDM optimizations show that high conversion (>80%) and total acid concentration
of 21.3 g/L are possible with 300 g substrate/(L liquid), 30 days liquid residence time, and 3 g/(L day) solid loading rate.
Thermophilic fermentation has a higher acetate content (∼63 wt%) than mesophilic fermentation (∼39 wt%). 相似文献
9.
Simşek O Buzrul S Akkoç N Alpas H Akçelik M 《Applied biochemistry and biotechnology》2009,158(2):387-397
The purpose of this study is to determine the survival and nisin production behaviors of two strains of Lactococcus lactis under different stress conditions that represent the food ecosystem. In this respect, the survival ratios of two nisin producers
were determined under different pH, temperature, NaCl, and bile salt concentrations. Then, nisin production levels of the
strains were determined at each stress conditions. Both strains had similar growth or inactivation patterns under the same
stress conditions. NaCl and bile salt stresses on the survival ratio of the strains could be successfully described by the
exponential decay function, whereas Gaussian function produced good fits for temperature and pH stresses. The nisin activity
of two nisin producers (in their mid-exponential and/or early stationary phase) decreased dramatically under all stress conditions,
except osmotic (NaCl) and low temperature applications. The results of this study showed that two nisin producers had similar
adaptive responses under severe stress conditions, which could be described by appropriate mathematical equations. Moreover,
the effect of harsh environment on the nisin activity of L. lactis strains depends on the stress factors applied. 相似文献
10.
Thereza Christina Vessoni Penna Angela Faustino Jozala Letícia Célia De Lencastre Novaes Adalberto Pessoa Jr. Olivia Cholewa 《Applied biochemistry and biotechnology》2005,122(1-3):619-637
Nisin is a bacteriocin that inhibits the germination and growth of Gram-positive bacteria. With nisin expression related to growth conditions of Lactococcus lactis subsp. lactis, the effects of growth parameters, media components, and incubation time were studied to optimize expression. L. lactis ATCC 11454 was grown (100 rpm at 30°C for 36 h) in both M17 and MRS standard broth media (pH 6.0–7.0) supplemented with sucrose (1.0–12.5 g/L), potassium phosphate (0.13 g/L), asparagine (0.5 g/L), and sucrose (0.24 g/L), and diluted 1:1 with liquid nonfat milk. Liquid nonfat milk, undiluted, was also used as another medium (9% total solids, pH 6.5). Nisin production was assayed by agar diffusion using Lactobacillus sake ATCC 15521 (30°C for 24 h) as the sensitive test organism. The titers of nisin expressed and released in culture media were quantified and expressed in arbitrary units (AU/L of medium) and converted into known concentrations of “standard nisin” (Nisaplin®, g/L). The detection of nisin activity was <0.01 AU/L in M17 and MRS broths, and 7.5 AU/L in M17 with 0.14% sucrose or 0.13% other supplements, and the activity increased to 142.5 AU/L in M17 diluted with liquid nonfat milk (1:1). The 25% milk added to either 25% M17 or 25% MRS provided the highest levels of nisin assayed. 相似文献
11.
Isci A Himmelsbach JN Strohl J Pometto AL Raman DR Anex RP 《Applied biochemistry and biotechnology》2009,157(3):453-462
Aqueous-ammonia-steeped switchgrass was subject to simultaneous saccharification and fermentation (SSF) in two pilot-scale
bioreactors (50- and 350-L working volume). Switchgrass was pretreated by soaking in ammonium hydroxide (30%) with solid to
liquid ratio of 5 L ammonium hydroxide per kilogram dry switchgrass for 5 days in 75-L steeping vessels without agitation
at ambient temperatures (15 to 33 °C). SSF of the pretreated biomass was carried out using Saccharomyces cerevisiae (D5A) at approximately 2% glucan and 77 filter paper units per gram cellulose enzyme loading (Spezyme CP). The 50-L fermentation
was carried out aseptically, whereas the 350-L fermentation was semiaseptic. The percentage of maximum theoretical ethanol
yields achieved was 73% in the 50-L reactor and 52–74% in the 350-L reactor due to the difference in asepsis. The 350-L fermentation
was contaminated by acid-producing bacteria (lactic and acetic acid concentrations approaching 10 g/L), and this resulted
in lower ethanol production. Despite this problem, the pilot-scale SSF of aqueous-ammonia-pretreated switchgrass has shown
promising results similar to laboratory-scale experiments. This work demonstrates challenges in pilot-scale fermentations
with material handling, aseptic conditions, and bacterial contamination for cellulosic fermentations to biofuels. 相似文献
12.
Silva NL Betancur GJ Vasquez MP Gomes Ede B Pereira N 《Applied biochemistry and biotechnology》2011,163(7):928-936
Current research indicates the ethanol fuel production from lignocellulosic materials, such as residual wood chips from the
cellulose industry, as new emerging technology. This work aimed at evaluating the ethanol production from hemicellulose of
eucalyptus chips by diluted acid pretreatment and the subsequent fermentation of the generated hydrolysate by a flocculating
strain of Pichia stipitis. The remaining solid fraction generated after pretreatment was subjected to enzymatic hydrolysis, which was carried out simultaneously
with glucose fermentation [saccharification and fermentation (SSF) process] using a strain of Saccharomyces cerevisiae. The acid pretreatment was evaluated using a central composite design for sulfuric acid concentration (1.0–4.0 v/v) and solid to liquid ratio (1:2–1:4, grams to milliliter) as independent variables. A maximum xylose concentration of 50 g/L
was obtained in the hemicellulosic hydrolysate. The fermentation of hemicellulosic hydrolysate and the SSF process were performed
in bioreactors and the final ethanol concentrations of 15.3 g/L and 28.7 g/L were obtained, respectively. 相似文献
13.
Clostridium acetobutylicum strains used in most Chinese ABE (acetone–butanol–ethanol) plants favorably ferment starchy materials like corn, cassava,
etc., rather than sugar materials. This is one major problem of ABE industry in China and significantly limits the exploitation
of cheap waste sugar materials. In this work, cane molasses were utilized as substrate in ABE production by Clostridium saccharobutylicum DSM 13864. Under optimum conditions, total solvent of 19.80 g/L (13.40 g/L butanol) was reached after 72 h of fermentation
in an Erlenmeyer flask. In a 5-L bioreactor, total solvent of 17.88 g/L was attained after 36 h of fermentation, and the productivity
and yield were 0.50 g/L/h and 0.33 g ABE/g sugar consumption, respectively. To further enhance the productivity, a two-stage
semicontinuous fermentation process was steadily operated for over 8 days (205 h, 26 cycles) with average productivity (stage
II) of 1.05 g/L/h and cell concentration (stage I) of 7.43 OD660, respectively. The average batch fermentation time (stage I and II) was reduced to 21−25 h with average solvent of 15.27 g/L.
This study provides valuable process data for the development of industrial ABE fermentation process using cane molasses as
substrate. 相似文献
14.
Spindler Diane D. Wyman Charles E. Grohmann Karel 《Applied biochemistry and biotechnology》1991,(1):773-786
Four promising woody crops (Populusmaximowiczii x nigra (NE388), P.trichocarpa x deltoides (Nll), P.tremuloides, and SweetgumLiquidambar styraciflua) were pretreated by dilute sulfuric acid and evaluated in the simultaneous saccharification and fermentation (SSF) process
for ethanol production. The yeastSaccharomyces cerevisiae was used in the fermentations alone, and in mixed cultures with β -glucosidase producingBrettanomyces dausenii. Commercial Genencor 150L cellulase enyme was either employed alone or supplemented with β- glucosidase. All SSFs were run at 37 …C for 8 d and compared to saccharifications at 45…C under the same enzyme loadings.S. cerevisiae alone achieved the highest ethanol yields and rates of hydrolysis at the higher enzyme loadings, whereas the mixed culture
performed better at the lower enzyme loadings without β -glucosidase supplementation. The best overall rates of fermentation
(3 d) and final theoretical ethanol yields (86–90%) were achieved with P.maximowiczii x nigra (NE388) and SweetgumLiquidambar styraciflua, followed by P.tremuloides and P.trichocarpa xdeltoides (N1l) with slightly slower rates and lower yields. Although there were some differences in SSF performance, all these pretreated
woody crops show promise as substrates for ethanol production. 相似文献
15.
Production of fuel ethanol from rye and triticale by very-high-gravity (VHG) fermentation 总被引:1,自引:0,他引:1
S. Wang K. C. Thomas W. M. Ingledew K. Sosulski F. W. Sosulski 《Applied biochemistry and biotechnology》1998,69(3):157-175
Very-high-gravity (VHG) rye and triticale mashes, containing about 28.5 g dissolved solids/100 mL of mash supernatant, were
prepared by adjusting water:grain ratios to 2:1. Because of high viscosity, which develops during mashing, it was necessary
to pretreat ground rye-water slurries with viscosity-reducing enzymes. There were no viscosity problems during the preparation
of triticale mashes. Fermentations were conducted at 20°C, with and without 16 mM urea as a nitrogenous supplement. All fermentations
were completed within 120–144 h. Supplementation with urea shortened the times required for completion of fermentation by
33% for triticale and by 40% for rye. The fermentation efficiencies for both grains ranged between 90 and 93%. These values
are comparable to those reported for wheat, implying competitiveness of rye and triticale as fermentation feedstocks to replace
wheat. The final ethanol yields were 409 L for rye and 417–435 L for triticale/t (dry basis). For a given size of fermentation
vessel, 33% more grain was used in the VHG fermentation process than in normal gravity fermentation. This resulted in a 35–56%
increase in ethanol concentration in the beer, when fermentors were filled to a constant volume. The corresponding reduction
in water use by about one-third would result in savings in energy consumption in mash heating, mash cooling, and ethanol distillation.
Fermentation efficiencies and final ethanol yields obtained per unit weight of grain fermented were not significantly different
from the normal gravity fermentations. 相似文献
16.
Xia WJ Luo ZB Dong HP Yu L Cui QF Bi YQ 《Applied biochemistry and biotechnology》2012,166(5):1148-1166
A bacterial strain was isolated and cultured from the oil excavation areas in tropical zone in northern China. The biochemical
characteristics and partial sequenced 16S rRNA gene of isolate, WJ-1, was identical to those of cultured representatives of
the species Pseudomonas aeruginosa. This bacterium was able to produce a type of biosurfactant. Compositional analysis revealed that the extracted biosurfactant
was composed of high percentage lipid (∼74%, w/w) and carbohydrate (∼20%, w/w) in addition to a minor fraction of protein (∼6%, w/w). The best production of 50.2 g/l was obtained when the cells were grown on minimal salt medium containing 6.0% (w/v) glucose and 0.75% (w/v) sodium nitrate supplemented with 0.1% (v/v) element solution at 37 °C and 180 rpm after 96 h. The optimum biosurfactant production pH value was found to be 6.0–8.0.
The biosurfactant of WJ-1, with the critical micelle concentration of 0.014 g/L, could reduce surface tension to 24.5 mN/m
and emulsified kerosene up to EI24 ≈95. The results obtained from time course study indicated that the surface tension reduction and emulsification potential
was increased in the same way to cell growth. However, maximum biosurfactant production occurred and established in the stationary
growth phase (after 90 h). Thin layer chromatography, Fourier transform infrared spectrum, and mass spectrum analysis indicate
the extracted biosurfactant was affiliated with rhamnolipid. The core holder flooding experiments demonstrated that the oil
recovery efficiency of strain and its biosurfactant was 23.02% residual oil. 相似文献
17.
Li S Li F Chen XS Wang L Xu J Tang L Mao ZG 《Applied biochemistry and biotechnology》2012,166(2):414-423
The productivity of ε-poly-l-lysine (ε-PL) in currently reported wild-type strains is low. Here we improved glucose tolerance of a Streptomyces graminearus strain LS-B1 by genome shuffling while simultaneously enhancing the ε-PL productivity. The starting population was generated
by ultraviolet irradiation and nitrosoguanidine mutagenesis and then subjected for recursive protoplast fusion. The positive
colonies from library, created by fusing the inactivated protoplasts were screened on agar plates containing different concentrations
of glucose. Characterization of all recombinants and wild-type strain in shake-flask fermentation indicated the compatibility
of two phenotypes of glucose tolerance and ε-PL yield enhancement. The best performing recombinant, F3-4, was isolated after
three rounds of genome shuffling, whose ε-PL production was about 88% higher than that of the parent strain. In batch fermentation
test, the ε-PL concentration was obtained as 2.4 g/L by F3-4 compared with 1.6 g/L of wild type. Fed-batch fermentation by
F3-4 was carried out and the ε-PL production accumulated to 13.5 g/L when initial glucose concentration was improved from
50 to 85 g/L. Enzyme activities of hexokinase, pyruvate kinase, and citrate synthase revealed that the glycolytic pathway
and tricarboxylic acid circle way in F3-4 were more active than those in wild type, which was a possible reason for enhanced
ε-PL production. 相似文献
18.
Lactococcus lactis CM1, an isolate from homemade “Dahi,” a traditional fermented milk from India, used maltose as carbon source to produce a
high level of bacteriocin. The bacterial cell mass and the bacteriocin production correlated with the initial pH of the medium
and were highest when the initial pH was 11.0. The level of bacteriocin reached its peak at the late log phase with concomitant
reduction of culture pH to 4.2, regardless of the initial pH of the medium. A combination of maltose and an initial medium
pH of 11 resulted in the highest bacteriocin production. The antibacterial spectrum of the bacteriocin was closely similar
to that of nisin and it inhibited a number of food spoilage and pathogenic bacteria. Upon sodium dodecyl sulfate polyacrylamide
gel electrophoresis, the compound migrated close to the position of nisin (3.5 kDa). However, it had higher stability than
nisin at a wide range of pH and temperature. PCR amplification using nisin gene-specific primers and sequencing of the amplified
DNA revealed the structural gene for the bacteriocin to be identical to that of nisZ. 相似文献
19.
High solids simultaneous saccharification and fermentation of pretreated wheat straw to ethanol 总被引:1,自引:0,他引:1
A. Mohagheghi M. Tucker K. Grohmann C. Wyman 《Applied biochemistry and biotechnology》1992,33(2):67-81
Wheat straw was pretreated with dilute (0.5%) sulfuric acid at 140°C for 1 h. Pretreated straw solids were washed with deionized
water to neutrality and then stored frozen at –20°C. The approximate composition of the pretreated straw solids was 64% cellulose,
33% lignin, and 2% xylan. The cellulose in the pretreated wheat straw solids was converted to ethanol in batch simultaneous
saccharification and fermentation experiments at 37°C using cellulase enzyme fromTrichoderma reesei (Genencor 150 L) with or without supplementation with β–glucosidase fromAspergillus niger (Novozyme 188) to produce glucose sugar and the yeastSaccharomyces cerevisiae to ferment the glucose into ethanol. The initial cellulose concentrations were adjusted to 7.5, 10, 12.5, 15, 17.5, and 20%
(w/w). Since wheat straw particles do not form slurries at these concentrations and cannot be mixed with conventional impeller
mixers used in laboratory fermenters, a simple rotary fermenter was designed and fabricated for these experiments. The results
of the simultaneous saccharification and fermentation (SSF) experiments indicate that the cellulose in pretreated wheat straw
can be efficiently fermented into ethanol for up to a 15% cellulose concentration (24.4% straw concentration). 相似文献
20.
de Lima CJ Ribeiro EJ Sérvulo EF Resende MM Cardoso VL 《Applied biochemistry and biotechnology》2009,152(1):156-168
Pseudomonas aeruginosa PACL strain, isolated from oil-contaminated soil taken from a lagoon, was used to investigate the efficiency and magnitude
of biosurfactant production, using different waste frying soybean oils, by submerged fermentation in stirred tank reactors
of 6 and 10 l capacities. A complete factorial experimental design was used, with the goal of optimizing the aeration rate
(0.5, 1.0, and 1.5 vvm) and agitation speed (300, 550, and 800 rpm). Aeration was identified as the primary variable affecting
the process, with a maximum rhamnose concentration occurring at an aeration rate of 0.5 vvm. At optimum levels, a maximum
rhamnose concentration of 3.3 g/l, an emulsification index of 100%, and a minimum surface tension of 26.0 dynes/cm were achieved.
Under these conditions, the biosurfactant production derived from using a mixture of waste frying soybean oil (WFSO) as a
carbon source was compared to production when non-used soybean oil (NUSO), or waste soybean oils used to fry specific foods,
were used. NUSO produced the highest level of rhamnolipids, although the waste soybean oils also resulted in biosurfactant
production of 75–90% of the maximum value. Under ideal conditions, the kinetic behavior and the modeling of the rhamnose production,
nutrient consumption, and cellular growth were established. The resulting model predicted data points that corresponded well
to the empirical information. 相似文献