Peel Residues Research Articles

Effective continuous acetone\u2013butanol\u2013ethanol production with full utilization of cassava by immobilized symbiotic TSH06

BackgroundButanol production by fermentation has recently attracted increasingly more attention because of its mild reaction conditions and environmentally friendly properties. However, traditional feedstocks, such as corn, are food supplies for human beings and are expensive and not suitable for butanol production at a large scale. In this study, acetone, butanol, and ethanol (ABE) fermentation with non-pretreated cassava using a symbiotic TSH06 was investigated.ResultsIn batch fermentation, the butanol concentration of 11.6 g/L was obtained with a productivity of 0.16 g/L/h, which was similar to that obtained from glucose system. A full utilization system of cassava was constructed to improve the fermentation performance, cassava flour was used as the substrate and cassava peel residue was used as the immobilization carrier. ABE fermentation with immobilized cells resulted in total ABE and butanol concentrations of 20 g/L and 13.3 g/L, which were 13.6% and 14.7% higher, respectively, than those of free cells. To further improve the solvent productivity, continuous fermentation was conducted with immobilized cells. In single-stage continuous fermentation, the concentrations of total ABE and butanol reached 9.3 g/L and 6.3 g/L with ABE and butanol productivities of 1.86 g/L/h and 1.26 g/L/h, respectively. In addition, both of the high product concentration and high solvent productivity were achieved in a three-stage continuous fermentation. The ABE productivity and concentration was 1.12 g/L/h and 16.8 g/L, respectively.ConclusionsThe results indicate that TSH06 could produce solvents from cassava effectively. This study shows that ABE fermentation with cassava as a substrate could be an efficient and economical method of butanol production.

Removal of Cr(VI) from water using pineapple peel derived biochars: Adsorption potential and re-usability assessment

In the present study, biochar was prepared using waste pineapple peel biomass with slow pyrolysis at 350, 450, 550 and 650°C to explore the effect of temperature treatment on characteristic properties of biochars. Various characterization parameters were analyzed to elucidate the temperature driven changes. Pyrolysis temperature had a significant impact on the properties of the developed biochar, leading to morphological and physiochemical changes. The relationship between pyrolysis temperature and induced physicochemical properties with Cr(VI) adsorption onto biochars was also investigated. Various adsorption parameters as pH (1.5–8), initial Cr(VI) concentration (10–500mg/L), biochar dose (0.5–10g/L) and adsorption time (0–96h) were studied. Freundlich isotherm (R2=0.957–0.972) and pseudo-second-order kinetics model (R2=0.981–0.994) best fitted the experimental data suggesting multilayer adsorption with chemical interactions between Cr(VI) ions and biochar surface. Biochar prepared at 350°C was found to have the highest adsorption capacity of 41.67mg/g among biochars. Complete Cr(VI) removal was achieved at 10mg/L Cr(VI) concentration with all the biochars. Rather than surface area polarity of biochar was found to be the influencing character of biochar for Cr(VI) adsorption. Feasibility of produced biochars for reuse was also explored. The study suggested that pineapple peel residue can be recycled to biochars with high carbon stability and can be used as a low-cost alternative adsorbent for wastewater treatment.

Chemical Pretreatments to Enrich the Acidogenic Phase in a System Coupled Packed Bed Reactor with a UASB Reactor Using Peels and Rotten Onion Waste

A large amount of onion wastes are produced by both domestically and industrially, making it necessary to search for a reuse process. These wastes causing odor and in some cases causes harm to the environment. At 2017, Mexico produced 1.6 million tons of which 10% are classified as organic waste. The aim of this study was to contribute to the reduction of onion peel residues, using chemical pretreatments (H2SO4, HCl, H3PO4 and NaOH) to enrich the acidogenic phase in the anaerobic digestion (AD) to improve the yield of methane in a system coupled packed bed reactor with an Up-flow Anaerobic Sludge Blanket reactor (UASB) using peels and rotten onion waste. In anaerobic digestion of white onion residues in a single stage (PBR1) presented inhibition due to the accumulation of VFA during the first days, which delay the onset of the methanogenic phase, which occurred 63 days after the start of the experiment. Pretreatment with H2SO4 (PBR2) decreased the start time of the methanogenic pathway, from 63 days to 35. In the same way, the coupling of the UASB reactor to the packed reactor (PBR3) allowed the decrease of the methanogenic step after 14 days, and the total time for this process was 35 days. The yield for PBR1 was 0.013 m3 CH4 kg VSrem−1, for PBR2 0.014 m3 CH4 kg VSrem−1 and PBR3 0.017 m3 CH4 kg VSrem−1. The total yield of PBR3 + UASB was 0.41 m3 CH4 kg VSrem−1.

Lime peel pectin integrated with coconut water and lime peel extract as a new bioactive film sachet to retard soybean oil oxidation

Lime peel pectin films incorporated with natural antioxidants from lime peel residue extract and using coconut water (CW) as a plasticizer were developed and applied as a sachet to retard the oxidation of soybean oil. The films prepared with CW as plasticizer had the lowest water solubility and were flexible compared to films prepared with glycerol as plasticizer. High water vapor permeability was observed in the films with higher plasticizer amounts in both CW and glycerol. However, the combination of CW and lime peel extract improved the film water barrier. The incorporation of lime peel extract in the film increased the total phenolic content and therefore enhanced the antioxidant activity of the film. Moreover, all lime peel pectin films retarded soybean oil oxidation during 30 days of storage. These results indicated that lime peel residue was a good source for pectin production and a natural antioxidant in bioactive films or coatings for various food applications.

Valorization of Orange Peel Residues via Fluidized Bed Torrefaction: Comparison between Different Bed Materials

ABSTRACTAn experimental study was carried out to evaluate an alternative disposal route for waste orange peels, which includes their upgrade into a solid biofuel and, possibly, the production of valuable liquid bio-chemicals via fluidized bed torrefaction. The influence of the torrefaction temperature (200 and 250°C), the reaction time (5 and 15 min) and the use of different bed materials (Ticino sand and γ-alumina spheres) on the distribution and composition of the main output products (torrefied solids, condensable volatiles and permanent gases) was investigated. Results show that the torrefaction at 250°C transforms orange peels from low-value residue to high-quality energy carrier by increasing their energy content (by a factor of 1.5) and reducing the O/C ratio (up to 67%). The temperature strongly influences the process performance and is the key process variable. Conversely, almost no effect were detected by changing the reaction time and the kind of granular solids on both the distribution and the composition of the main torrefaction products. Although γ-alumina does not exhibit a remarkable catalytic activity in the investigated temperature range, its use instead of sand is recommended as its lower density makes the bed smoother to be fluidized.

Semi‐Siccative Oils and Bioactive Fractions Isolated from Reunion Island Fruit Co‐Product: Two Case Studies

This paper focused on the use of agro‐industrial wastes of strawberry guava (Psidium cattleianum) and passion fruit (Passiflora edulis) generated by the agricultural industry on Reunion Island, according to two routes: extraction of semi‐siccative oils from the seeds and extraction of bioactive compounds from residual pulp and peels. Oil content, fatty acid, carotenoids, tocopherol, and sterol concentrations are determined in the seed oils obtained by four different extraction processes using Soxhlet extraction, extraction by hexane and ethanol, mechanical pressing and supercritical‐carbon dioxide (SC‐CO2) extraction. The oil extraction yields ranged from 15 to 30% w/w for strawberry guava and passion fruit, respectively. Both oils are classified as semi‐siccative and had a similar total unsaturated fatty acid content (88%) with a prevalence of linoleic acid (70–78%). High contents in phytosterols and in α‐tocopherol are particularly detected in strawberry guava oil. The antioxidant activities of the bioactive compounds extracted by water and ethanol from pulp and peels are characterized by α,α‐diphenyl‐β‐picrylhydrazyl (DPPH) test. After purification on polymeric resin, significant antioxidant activities are recorded (half maximal inhibitory concentration (IC50) from 11 to 50 g L−1) and are related to polyphenol contents (20.7 to 42.5 g gallic acid equivalents (GAE)/100 g dry extract).Practical Applications: There is a great interest on the use of tropical fruit wastes because of their large availabilities. Strawberry guava and passion fruit are often used in the food industry, for juice and jam production. The seeds, pulp, and peel residues are in fact a by‐product of their industrial processing, which should be valuably processed instead of just throwing away. We can state that the extracted seed (rich in polyunsaturated fatty acids) of strawberry guava and passion fruit can be used in the industrial production of emulsions, paints, and varnishes. Within the positive aspects of the study, one can also distinguish the use of these tropical fruit by‐products as beneficial sources of many valuable bioactive compounds, for example, carotenoids, tocopherols, phytosterols, and especially polyphenols, for functional formulations. Moreover, it may be the experimental basis for further development and use in food industryGreen extraction processes are applied to two tropical fruit coproducts. Seed oils obtained are rich in unsaturated fatty acids (88%). Strawberry guava oil has high contents in α‐tocopherol and in sterols. Functional organic molecules are also isolated from residual peels and pulps. Results shows that strawberry guava extracts have antioxidant activities similar to Trolox.

Copper adsorptive removal from aqueous solution by orange peel residue carbon nanoparticles synthesized by combustion method using response surface methodology

In the present study, new and low-cost orange peel residue carbon nanoparticles as an adsorbent for the removal of copper ions was prepared. The orange peel residue carbon nanoparticles were synthesized by combustion technique by urea as fuel, and characteristics were analysed with BET, FESEM, and FTIR tests. FESEM and BET analysis display smaller particle size (100% below 30 nm), regular and narrow particle size distribution and higher specific surface area for combustion synthesized sample. The central composite design (CCD) under response surface methodology (RSM) by Design Expert software was employed to evaluate the effect of solution pH, initial copper concentration, contact time, and the ratio of fuel to adsorbent (F/A) on the removal efficiency of copper ions. Results of analysis of variance (ANOVA) showed that the initial copper concentration and pH were the most significant parameters for Cu2+ removal. The optimization of Cu2+ removal was carried out by four parameters (pH, the initial concentration of the Cu2+ solution, contact time and F/A) that were chosen in five surfaces. The numerical optimization showed that the optimum removal (94%) obtained at pH = 5, initial Cu2+ concentration = 36 ppm, contact time = 75 min, and F/A = 0.96. The experimental isotherm data were analysed using Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich (D–R) isotherms. The Temkin equation was found to be in good accordance with equilibrium data for Cu2+ adsorption onto OPCM. The results indicated that the orange peel nanoparticle is efficient and economical for Cu2+ ions removal from aqueous solution.

A co-immobilization of pectinase and cellulase onto magnetic nanoparticles for antioxidant extraction from waste fruit peels

Abstract The major obstruction in efficient extraction of intracellular bioactive components is highly complex cell wall structure which is made up of rigid polysaccharides. An enhancement in the release of bioactive compounds from plants and fruits can be facilitated by hydrolysing cellular cellulosic material along with pectin. In this context, co-immobilized magnetic nanobiocatalyst was prepared by simultaneous immobilization of Pectinex® and Celluclast® 1.5 L onto amino-functionalized magnetic nanoparticles (MNPs) by 75 mM cross-linker concentration (glutaraldehyde) with 12.5 h cross-linking time for efficient extraction. The prepared nanobiocatalyst was characterized by FT-IR, TGA, SEM and XRD. In thermal stability studies, magnetic nanobiocatalyst showed two folds increased half-life in the temperature range of 50–70 °C as compared to native form. Further, the magnetic biocatalyst retained up to 80% of residual activity even after ten successive cycles. At the end, the antioxidants were extracted from peel residues of orange, mango and banana by using co-immobilized magnetic nanobiocatalyst and mixture of individually immobilized enzymes. This showed more than two fold higher free radical scavenging activity as compared to conventional solvent based extraction.

Pyrus pyrifolia fruit peel as sustainable source for spherical and porous network based nanocellulose synthesis via one-pot hydrolysis system

In the present study, we attempted revalorization of pear (Pyrus pyrifolia L.) peel residue into high value-added nanomaterials. A green and facile one-pot isolation procedure was designed to simplify the isolation process of nanocellulose directly from pear peel residue. The one-pot approach employed in this work is interesting as the reaction involved less harmful chemicals usage and non-multiple steps. The reaction was carried out by adding hydrogen peroxide as an oxidant and chromium (III) nitrate as catalyst in the acidic medium under mild process conditions. FTIR spectroscopy proved that the pear peel derived nanocellulose was purely cellulose phases without the presence of non-cellulosic layer. XRD study indicated that the isolated nanocellulose possessed of cellulose I polymorph with high crystallinity index of 85.7%. FESEM analysis clearly revealed that the considerable size reduction during one-pot process. Remarkably, TEM analysis revealed that the isolated nanocellulose consisted of network-liked nature and spherical shaped morphologies with high aspect ratio of 24.6. TGA showed nanocellulose has lower thermal stability compared to pear peel residue. This study provided a cost-effective method and straightforward one-pot process for fabrication of nanocellulose from pear peel residue. This is the first investigation on the nanocellulose extraction from pear fruit.

Utilization of Lignocellulose-based Orange Peel Waste for Induced Sporulation of Trichoderma asperellum via Box-Behnken Matrix Design

The feasibility of using orange peel residues as a substrate for induced sporulation of Trichoderma asperellum was evaluated. The Box-Behnken matrix (BBM) design was used to screen the effects of several parameters, including the effect of pH, inoculum, and moisture under solid-state fermentation culture conditions. The study was performed in two experimental steps (screening and optimization). Moisture content and pH were determined to be the most influential parameters on spore production during the screening stage. A Box-Behnken design was used to optimize and to define the interaction of the selected parameters. The moisture content was determined as the most significant parameter affecting spore production. An inoculum of 1 × 106 spores g-1, pH 6.07, and moisture content of 69.0% was the combination of conditions observed to achieve the maximum production of 2.04 × 109 spores g-1. The experimental value of 2.16 × 109 spores g-1 (from the experimental model) showed a good fit to the regressed model, with a standard error of 5%. Based on this work, a high yield of spores was obtained at 144 h of cultivation time, indicating that it is a feasible approach to use orange peel as a substrate for biomass and spore production.

DIVERSIFIKASI RESIDU PRODUK OLAHAN HOME INDUSTRY SIRUP JERUK KALAMANSI DI KABUPATEN BENGKULU TENGAH

Community Service Activities for Residual Diversification of Processed Products Home Industry Syrup Kalamansi in Bengkulu Tengah has been completed. This activity aims to reduce the residual volume of unused Kalamansi syrup yields, the production of high value essential oils and various essential and economically valuable essential oil-based citrus oil products. In this activity we have conducted training on the way of extraction of essential oil from citrus peel residue and crude fiber (dregs) leftover of Kalamansi syrup using direct steam distillation method, followed by training of various essential oil based health products in form of aromatherapy roll oil, and Antiseptic liquid soap. From the results of the activities that have been done, the essential oil from the residue of K alamansi syrup made of clear liquid smelling orange K alamansi. It has also been produced several products made from active essential oil of orange Kalamansi such as wind oil roll on, liquid bath soap, lotion and liquid washing soap. The four products have a typical citrus scent K alamansi, but need to be refined formula to produce a quality product and selling value. Keywords : Citrus Kalamansi, Steam Distillation, essential oils, wind aromatheraphy oil.

Orange processing waste valorisation for the production of bio-based pigments using the fungal strains Monascus purpureus and Penicillium purpurogenum

Abstract Orange processing wastes have been evaluated for the production of pigments by the fungal strains Monascus purpureus ATCC 16365 and Penicillium purpurogenum CBS 113139. Solid state fermentations were initially conducted on waste orange peels with the fungal strain M. purpureus aiming to assess various pigment extraction methods, the effect of particle size as well as the effect of nitrogen addition and incubation time. Under the optimum conditions, solid state fermentations were also performed with the strain P. purpuronegum to evaluate pigment production on waste orange peels. M. purpureus was more efficient than P. purpurogenum for the production of pigments during solid state fermentation, yielding 9 absorbance units (AU) per g of dry fermented substrate. Semi-solid state fermentations were subsequently conducted by suspending waste orange peels in liquid media leading to pigment production of up to 0.95 AU mL−1. Submerged fermentations were carried out with both fungal strains using aqueous extracts from either boiled or hydrodistilled orange peel residues as the sole fermentation medium showing that up to 0.58 AU mL−1 of pigment production could be achieved. Each fermentation feedstock and fermentation mode influenced significantly the production of pigments by each fungal strain used.

Evaluation of different biological and chemical treatments in agroindustrial residues for the production of fungal glucanases and xylanases

The production and use of fibrolytic enzyme complex in the hydrolysis of lignocellulosic materials is an important strategy for renewable bioenergy. The different carbon sources (residues) with or without some pretreatments (biological or chemical) were analyzed in order to increase the production of fibrolytic enzyme. Glycosyl hydrolases and xylanases were produced using Trichoderma reesei QM9414. The influence of some crude or pre-treated agro-industrial residues as a carbon source was previously investigated using shake-flask cultures. Subsequently, the selection of the best culture medium was studied under different pH and temperature conditions in stirred tank bioreactor. Fibrolytic activities reached a maximum of 0.85 ± 0.07 FPU mL−1 (total cellulase), 3.14 ± 0.01 CMC mL−1 (endoglucanase) and 1.25 ± 0.14 U mL−1 (exoglucanase) with the orange peel residue; and 93.08 ± 3.27 U mL−1 (xylanase) with sugarcane bagasse under alkali pretreatment. In the stirred tank bioreactor the cellulolytic activity increased to 1.76 ± 0.00 FPU mL−1, about 2 times higher than in the shake-flasks or under studied conditions. The biosynthesis of the fibrolytic complex using agroindustrial residues supplemented was shown to reach a higher total cellulose production.

Effect of Ultra-fine Pulverization on the Properties of Tomato Peel Residues

To investigate the effect of ultra-fine pulverization technology on properties of tomato peel residues, a series of analytical techniques including laser particle size analysis, scanning electron microscopy, X-ray energy-dispersive spectroscopy, infrared spectroscopy, zeta potential and antioxidant activity assay have been applied to comparative analysis of particle size distribution, specific surface area, microstructure, absorption intensity ratio of chemical functional groups, stability and solubility of dispersion solution, in vitro antioxidative activity and other biological activities of the powder samples prepared from tomato peel residues subjected to ultra-fine pulverization. The results showed that the structure and cell wall of the ultra-fine powder (300 mesh powder) prepared from tomato peel residues revealed more serious damage when compared with the coarse powder (80 mesh powder), the smaller diameter of the 300 mesh powder was reduced by 10 times, but the specific surface area of the 300 mesh powder was increased by four times when compared with the 80 mesh powder; meanwhile, the relative content of each functional group with high absorption intensity was higher than that in 80 mesh powder prepared from tomato peel residues; in addition, the dispersion stability of 300 mesh powder from tomato peel residues was better than that of 80 mesh powder in aqueous solution. Moreover, in vitro antioxidant activity of ultra-fine power was significantly higher than that of the coarse power. This study may help for tomato in deep processing.

Improving Polyphenol Extraction from Lemon Residues by Pulsed Electric Fields

In this contribution, the influence of Pulsed Electric Fields (PEF) of different intensities (3–9 kV/cm and 0–300 μs) on the extraction of Total Phenols from lemon peel residues by pressing was investigated. According to the cellular disintegration index, the optimum treatment time for the increase in permeability was determined as 30 pulses of 30 μs. It was determined that the effect of PEF was independent of lemon residue size. The effectiveness of pressing-assisted extraction was evaluated by measuring the Total Phenol Content (TPC), the real antioxidant capacity and the concentrations of the main lemon polyphenols, the flavonones hesperidin and eriocitrin. The variables studied in the extraction were time, pressure applied and intensity of the electric fields. This study concludes that electric field intensity of 7 kV/cm increased the efficiency of polyphenol extraction by 300%, giving maximum values of 84 mg of hesperidin in 100 g FW and 176 mg of eriocitrin in 100 g FW. Thus, it was concluded that PEF provides a new methodology to improve polyphenol extraction with a non-thermal, environment-friendly technology, and this represents a method for increasing economic benefits of industrial processes.

Syngas production by catalytic steam gasification of citrus residues

This study investigate the feasibility to use citrus peel residues to produce hydrogen rich syngas by steam gasification process. Thermodynamic evaluations were performed by simulation modelling thus preliminary experiment was carried out at 1023 K and S/B ratio 1.5 wt/wt. The effect of different types of catalytic materials (minerals and synthetic catalyst) on steam gasification process was investigated in terms of efficiency, hydrogen formation tendency and outlet stream composition.It is found that concentrations of H2 and CO of 58.80 mol% and 25.34 mol% can be produced by citrus peels conversion. Moreover, both carbon and hydrogen gasification efficiencies can be enhanced using dolomite, MgO and Ni/Al2O3 in the reactor (from 43.7% to 54.9% and from 34.3% to 54.1% for CGE and H2GE, respectively). Dolomite resulted the best catalyst for citrus peels steam gasification under the examined operative condition with CGE and H2GE rates of 54.9% and 54.1%, respectively. Ni catalyst resulted to be affected by carbon formation and sintering on time on stream.

Synthesis and Characterization of Nanocrystalline Cellulose Derived from Pineapple Peel Residues

Synthesis and Characterization of Nanocrystalline Cellulose Derived from Pineapple Peel Residues

APROVECHAMIENTO DE LOS RESIDUOS SÓLIDOS ORGÁNICOS DE LAS FRUTAS MEDIANTE DIGESTIÓN ANAEROBIA

Debido al gran volumen de residuos de frutas que se generan diariamente en diversas operaciones relacionadas con el procesamiento de frutas, verduras, entre otros, y las actividades económicas de origen agroindustrial, se plantea que es posible realizar la digestión anaeróbica de estos residuos biodegradables. Es por esta razón que la investigación tiene como finalidad discutir las bases teóricas que fundamentan el aprovechamiento de los residuos sólidos orgánicos de las frutas mediante procesos de digestión anaerobia. En la actualidad los residuos sólidos orgánicos (fracción húmeda) de la industria no tienen un objetivo específico para su uso, la mayoría de ellos son enviados al basurero. Dada la necesidad de aprovechar los residuos de cáscaras de frutas se requieren biorreactores debidamente diseñados y construidos. El uso de combinaciones de residuos sólidos orgánicos de las frutas en procesos de digestión anaeróbica puede potenciar la producción o rendimiento de metano y a su vez generar mayor productividad y factibilidad desde la perspectiva económica. En este sentido, la piña y naranja pueden ser evaluadas para determinar la relación óptima para obtener mayores rendimientos de producción energética (metano). Palabras clave: bioconversión, metano, subproductos, frutas, digestión anaerobia.

Hydrogen rich syngas production by air-steam gasification of citrus peel residues from citrus juice manufacturing: Experimental and simulation activities

Hydrogen rich syngas could play a relevant role as clean source of energy and chemicals. Further environmental and economic advantages can be reached if syngas is produced by residues or wastes. This work aims at exploring the potential of citrus peel (CP) air-steam gasification for the production of hydrogen rich syngas. The study of the gasification process was developed by means of a bench-scale fluidized bed reactor, which operates in a temperature range of 700–850 °C and with a variable steam to biomass ration (S/B) from 0.5 to 1.25. The experimental results were used to validate a developed air-steam gasification model. Limited to the investigated conditions, both experimental and model results found that the highest hydrogen yield was obtained at 750 °C and S/B = 1.25, reaching 0.65 and 0.69 Nm3/kgbiom respectively. The pyrolysis results have been used for simulating the pyrolysis step that is part of the gasification model. The gasification and combustion steps were modeled using a thermodynamic approach based on the minimization of the Gibbs free energy.

Optimization of enzymatic hydrolysis and fermentation conditions for improved bioethanol production from potato peel residues.

The aim of this work was the optimization of the enzyme hydrolysis of potato peel residues (PPR) for bioethanol production. The process included a pretreatment step followed by an enzyme hydrolysis using crude enzyme system composed of cellulase, amylase and hemicellulase, produced by a mixed culture of Aspergillus niger and Trichoderma reesei. Hydrothermal, alkali and acid pretreatments were considered with regards to the enhancement of enzyme hydrolysis of potato peel residues. The obtained results showed that hydrothermal pretreatment lead to a higher enzyme hydrolysis yield compared to both acid and alkali pretreatments. Enzyme hydrolysis was also optimized for parameters such as temperature, pH, substrate loading and surfactant loading using a response surface methodology. Under optimized conditions, 77 gL-1 of reducing sugars were obtained. Yeast fermentation of the released reducing sugars led to an ethanol titer of 30 gL-1 after supplementation of the culture medium with ammonium sulfate. Moreover, a comparative study between acid and enzyme hydrolysis of potato peel residues was investigated. Results showed that enzyme hydrolysis offers higher yield of bioethanol production than acid hydrolysis. These results highlight the potential of second generation bioethanol production from potato peel residues treated with onsite produced hydrolytic enzymes. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:397-406, 2017.