Sweet Potato Starch Wastewater Research Articles

Protein recovery from sweet potato starch wastewater using modified chitosan

This study reports an effective method to explore the significant role of modified chitosan in recovering a protein from starch wastewater of sweet potato. Fourier transform infrared (FT-IR) spectroscopy, energy dispersive X-ray analysis (EDX), polarizing optical microscopy (POM), and scanning electron microscope analysis (SEM) are used to characterize modified chitosan. Parameters, such as agitation time, chitosan dose, initial pH, and settling time, are monitored over the protein recovery process. Also, the second-order polynomial model was developed with Box Behnken design (BBD). 3-D response surface contour graphs are plotted to learn about the interactive effects of process parameters on protein recovery. The optimum operating conditions are determined by using the desired function methodology. Under these optimal conditions, 95% of the protein was recovered. An artificial neural network (ANN)-based model was developed for simulating protein recovery. Electrophoresis analysis has shown that recovered protein can be used as livestock feed ingredients.

Efficient Treatment of the Sweet Potato Starch Wastewater by Enhanced Flocculation–Coagulation of Environmentally Benign Materials

Efficient Treatment of the Sweet Potato Starch Wastewater by Enhanced Flocculation–Coagulation of Environmentally Benign Materials

Extraction and profiling of proteins in yellow powder from sweet potato starch wastewater using response surface methodology and proteomic approach.

Sweet potato starch industry produce generous high soluble solid wastewater containing various biochemicals such as proteins. The wastewater could be spray dried into a product called yellow powder (YP). Proteins in the YP were recovered and profiled in this study. The extraction conditions were optimized on dependent variables of YP material-water ratio, pH, and temperature using response surface methodology (RSM). Maximum protein yield (61.2%) using RSM were observed at a material-water ratio of 50 (mg/L), pH 9.5, and extraction temperature of 30℃. Subsequently, a total of 25 proteins were identified by proteomic analysis, which mainly were sporamins, β-amylase, starch phosphorylase, polyphenol oxidase, and superoxide dismutase. The extraction and profiling of proteins from YP would contribute to a comprehensive utilization and added value of the wastewater produced by sweet potato starch processing industry. PRACTICAL APPLICATION: This study reported the recovery (61.2%) of proteins and protein profile of yellow powder (byproducts) from sweet potato starch wastewater. These information could contribute to the valorization a yellow powder into high-value ingredients.

Utilization of Ultrafiltration Technology in the Treatment of Sweet Potato Starch Production Wastewater

In order to select a suitable ultrafiltration membrane to treat sweet potato starch wastewater, five different ultrafiltration membranes, including three ceramic membrane (N50, N100 and N200) and two organic membrane (PVDF and PES), were selected to study their effects on three kinds of wastewater from the production process of sweet potato starch. The results showed that all membrane flux decreased significantly in the time of 15 to 25 minutes and then maintained basically stable, of which the ceramic membrane N200 and N50 had relatively high stable membrane flux and the membrane flux of PVDF was higher than that of PES. After ultrafiltration, the light transmittance of wastewater was increased significantly, the remove rates of soluble solids, soluble protein and COD were 39.8%~64.6%, 73.7%~99.0% and 32.3%~73.2%, respectively. The performance of membrane N50, PVDF and PES was better than others. Considering the membrane flux and separation effectiveness, the membrane N50 or PVDF was recommended for further reducing the pressure of subsequent treatment and improving the recovery and of organic compounds in wastewater.

Nanoparticle as a novel foam controller for enhanced protein separation from sweet potato starch wastewater

This is an article describing a novel technology where hydrophobic nanoparticle acts as a foam controller to facilitate protein separation. Valuable sweet potato protein (SPP), a protein model, mainly exits in sweet potato starch wastewater (SPSW), and its separation is desperately needed to enable a sustainable utilization of waste and reduce the environmental burden. We firstly used hydrophobic silica nanoparticle (SNP) in situ modified by dodecyl dimethyl betaine (BS12) as a foam stabilizer instead of surfactants to improve SPSW foam stability. Somewhat unexpectedly, the particle also intensified the interfacial adsorption of SPP. Subsequently, a foam separation column with a vertical ellipsoid-shaped channel (VEC) was proposed to gently strengthen foam drainage and then enhance the enrichment ratio of SPP (ESPP). Most importantly, the negative impact of VEC on the recovery percentage of SPP (RSPP) was found to be negligible in the presence of modified SNP because it maintained the film thickness. After the foam separation, unmodified SNP served as a defoamer to accelerate bubble breakage. Eventually, RSPP and ESPP reached 80.6 ± 4.0% and 9.1 ± 0.5, respectively, using the SNP as a foam controller. We expect this technology to be a complementary and/or alternative strategy for protein separation.

The performance and archaeal community shifts in a modified anaerobic baffled reactor treating sweet potato starch wastewater at ambient temperatures

A conventional anaerobic baffled reactors (ABRs) treating high strength sweet potato starch wastewater at ambient temperatures resulted in acidification and bad performances. After modification, the acidification was remitted and COD removal efficiencies reached 92.73% at high temperatures and were maintained at 71.19% at low temperatures. Moreover, as much as 1.014 ± 0.056 L CH4/L/d were collected at Stage III. The q-PCR results revealed that the largest methanogen populations emerged at Stage III as well, which was 5.29 × 108 mcrA copies per milliliter sludge. A comparable shift in the archaeal community structure at different stages and acetoclastic methanogens Methanosaeta predominated the archaeal community in every compartment in Stages I (63.73%) and II (48.63%). Finally, the net energy gains analysis at mesophilic, thermophilic, and ambient temperature revealed that modified ABR at ambient temperature was not only economical but also profitable and could generated 3.68 KJ energy per gram COD removed.

Manipulation of nitrogen leaching from tea field soil using a Trichoderma viride biofertilizer.

With the increasing use of chemical fertilizers, negative environmental impacts have greatly increased as a result from agricultural fields. The fungus Trichoderma viride used as a biofertilizer can efficiently reduce nitrous oxide (N2O) emissions from subtropical tea fields in southern China. In this paper, it was further found that T. viride biofertilizer could alleviate nitrogen (N) leaching in tea fields. Gross N leaching was 1.51kgha-1year-1 with no external fertilizer input, but when 225kgNha-1year-1was applied, it increased to 12.38kgha-1year-1 using T. viride biofertilizer but 53.46kgha-1year-1 using urea. Stepwise linear regression analysis identified the factors responsible for N leaching to be soil nitrate concentration and soil interflow, simulated here using the water balance simulation model (WaSiM-ETH). Finally, mass-scale production of T. viride biofertilizer from waste reutilization using sweet potato starch wastewater and rice straw was found to be cost-effective and feasible. These procedures could be considered a best management practice to reduce N leaching from tea fields in subtropical areas of central China and to reduce pollution from other agricultural waste products.

Occurrence and transformations of carbon, nitrogen, and phosphorus related to particle size fraction of sweet potato starch wastewater during hydrolytic acidification processes.

Sweet potato starch wastewater (SPSW) is an industrial food-processing waste product, which is a significant pollution source due to its high chemical oxygen demand (COD), nitrogen, and phosphorus loads. The influence of hydrolytic acidification (HA) process on C, N, and P as well as other main parameters were evaluated. It is essential to treat these wastewaters with effective methods such as HA, a general pretreatment application. In this study, we investigate the scientific link between the changes of different fractions of C, N, and P with particle size distribution in response to the newly introduced HA process. Results showed that the levels of COD, TN, and TP remained ultimately stable; pH and suspended solids (SSs) decreased obviously. HA process exhibits excellent capability of reducing the larger particulars (with diameter of >5μm) into smaller ones (with diameter of <0.1μm). The most significant initial concentration contribution to COD, TN, and TP pollution came from particles and matter with a diameter of >5μm, at 41.8, 57.3, and 43.5%, respectively. While the most significant contribution to COD, TN, and TP was resulting from micro-molecular size particles (<0.1μm) after 48h. The smallest particles (<0.1μm) were the most dominant contribution to all pollutants measured, with COD, TN, and TP contributions of 63.2, 50.4, and 59.3%, respectively. While the contribution of larger particles (particle size >5μm) reduced to 10.2, 15.3, and 7.1%, respectively.

Effect of Trichoderma viride biofertilizer on ammonia volatilization from an alkaline soil in Northern China

Ammonia (NH3) volatilization is one of the primary pathways of nitrogen (N) loss from soils after chemical fertilizer is applied, especially from the alkaline soils in Northern China, which results in lower efficiency for chemical fertilizers. Therefore, we conducted an incubation experiment using an alkaline soil from Tianjin (pH8.37–8.43) to evaluate the suppression effect of Trichoderma viride (T. viride) biofertilizer on NH3 volatilization, and compared the differences in microbial community structure among all samples. The results showed that viable T. viride biofertilizer (T) decreased NH3 volatilization by 42.21% compared with conventional fertilizer ((CK), urea), while nonviable T. viride biofertilizer (TS) decreased NH3 volatilization by 32.42%. NH3 volatilization was significantly higher in CK and sweet potato starch wastewater (SPSW) treatments during the peak period. T. viride biofertilizer also improved the transfer of ammonium from soil to sweet sorghum. Plant dry weights increased 91.23% and 61.08% for T and TS, respectively, compared to CK. Moreover, T. viride biofertilizer enhanced nitrification by increasing the abundance of ammonium-oxidizing archaea (AOA) and ammonium-oxidizing bacteria (AOB). The results of high-throughput sequencing indicated that the microbial community structure and composition were significantly changed by the application of T. viride biofertilizer. This study demonstrated the immense potential of T. viride biofertilizer in reducing NH3 volatilization from alkaline soil and simultaneously improving the utilization of fertilizer N by sweet sorghum.

Hydrogen and lipid production from starch wastewater by co-culture of anaerobic sludge and oleaginous microalgae with simultaneous COD, nitrogen and phosphorus removal

Anaerobic sludge (AS) and microalgae were co-cultured to enhance the energy conversion and nutrients removal from starch wastewater. Mixed ratio, starch concentration and initial pH played critical roles on the hydrogen and lipid production of the co-culture system. The maximum hydrogen production of 1508.3 mL L−1 and total lipid concentration of 0.36 g L−1 were obtained under the optimized mixed ratio (algae:AS) of 30:1, starch concentration of 6 g L−1 and initial pH of 8. The main soluble metabolites in dark fermentation were acetate and butyrate, most of which can be consumed in co-cultivation. When sweet potato starch wastewater was used as the substrate, the highest COD, TN and TP removal and energy conversion efficiencies reached 80.5%, 88.7%, 80.1% and 34.2%, which were 176%, 178%, 200% and 119% higher than that of the control group (dark fermentation), respectively. This research provided a novel approach and achieved efficient simultaneous energy recovery and nutrients removal from starch wastewater by the co-culture system.

Protein Recovery from Sweet Potato Starch Wastewater by Foam Separation

In this study, an inclined foam separation column was designed to effectively recover protein from sweet potato starch wastewater. The effects of the influent protein concentration, pH, air flow rate, influent volume, foaming time, and inclined column angle on foam separation performance were assessed. The optimum foam separation conditions consisted of influent protein concentration 4.51 mg/mL, pH 4, air flow rate 0.15 mL/min, influent volume 500 mL, foaming time 100 min, and inclined column angle 30°. In these conditions, protein recovery percentage and enrichment ratios were 84.1% and 1.3, respectively. The biochemical oxygen demand (BOD5) and chemical oxygen demand (CODCr) of the residual solution (620 and 950 mg/mL, respectively) were lower than those of the original (influent) solution.

Mitigating nitrous oxide emissions from tea field soil using bioaugmentation with a Trichoderma viride biofertilizer.

Land-use conversion from woodlands to tea fields in subtropical areas of central China leads to increased nitrous oxide (N2O) emissions, partly due to increased nitrogen fertilizer use. A field investigation of N2O using a static closed chamber-gas chromatography revealed that the average N2O fluxes in tea fields with 225 kg N ha−1 yr−1 fertilizer application were 9.4 ± 6.2 times higher than those of woodlands. Accordingly, it is urgent to develop practices for mitigating N2O emissions from tea fields. By liquid-state fermentation of sweet potato starch wastewater and solid-state fermentation of paddy straw with application of Trichoderma viride, we provided the tea plantation with biofertilizer containing 2.4 t C ha−1 and 58.7 kg N ha−1. Compared to use of synthetic N fertilizer, use of biofertilizer at 225 kg N ha−1 yr−1 significantly reduced N2O emissions by 33.3%–71.8% and increased the tea yield by 16.2%–62.2%. Therefore, the process of bioconversion/bioaugmentation tested in this study was found to be a cost-effective and feasible approach to reducing N2O emissions and can be considered the best management practice for tea fields.

Study on Environmental Materials with Treatment of Sweet Potato Starch Wastewater by Hydrolysis Acidification Sedimentation Process

This study aimed at the application conditions of environmental materials in sweet potato starch wastewater by hydrolysis acidification process. The removal rates of COD and soluble protein were investigated to find suitable natural setting time, the quantity of acidic steeping liquor and pH. The results showed that traditional fermentation not only consumes time but also scarcely removal efficiency in short time. 40% acidic steeping liquor was added as an optimum dosage for effective treatment. In addition, the effort of pH (3.0-9.0) on the hydrolysis acidification of wastewater was investigated. The removal rates of COD and soluble protein reached 26.9% and 76.3% respectively at pH4.0. Therefore, pH was adjusted to isoelectric point that can effectively reduce the burden of subsequent wastewater treatment.

Study on Environmental Materials with Treatment of Sweet Potato Starch Wastewater by Coagulation Precipitation Method

This study aimed at, pre-treatment of sweet potato starch wastewater and acquisition the application conditions of environmental materials though coagulation precipitation. The removal rates of COD and turbidity were investigated by process to find kind and quantity of suitable coagulant, quantity of coagulate aids, pH and setting time. The results showed that poly aluminum ferric chloride (PAFC) was chosen as an optimum coagulant for effective treatment. The optimal coagulation precipitation conditions were determined as follows: pH8, dosage of PAFC 1200mg/l, PAM100mg/l, sedimentation time 30 min. At optimum conditions of coagulation precipitation stages, the removal rate of COD and turbidity reached 25.8% and 67.5%, respectively. Therefore, coagulation process reduced the burden of subsequent wastewater treating.

Treatment of Sweet Potato Starch Wastewater with UASB

A pilot-scale upflow anaerobic sludge blanket (UASB) reactor was used to study the sweet potato starch wastewater treatment performance and its influencing factors. Under normal temperature conditions, the operating parameters of sweet potato starch wastewater from UASB treatment was optimized, and the better conditions from different influent CODcr concentrations was obtained. The impacts from trace elements MgCl2, FeCl2, CoCl2, NiCl2 on physiological and biochemical characteristics of anaerobic granular sludge was developed.

Operating Characteristic of IC Reactor Treating Wastewater of Sweet Potato Starch

The operating characteristics of IC reactor were studied when wastewater of sweet potato starch was utilized to domesticate the granular sludge. The effect of temperature on the treatment of sweet potato starch wastewater using IC reactor was specially researched. Results showed that the COD removal rate improved gradually in the process of the granular sludge in the IC reactor was domesticated by wastewater of sweet potato starch, and the activity of granular sludge also increasingly recovered. When the domestication was finished, the volume loading rate and the COD removal rate could attain 21.9kgCOD/ (m3 •d) and 84%, respectively. When the system temperature was between 29～35°C,the COD removal rate could be above 80%. However, when the temperature decreased, the COD removal rate reduced sharply.