It has been proven that the work described in this thesis entitled "Integrated bioprocess design and development strategies for the production of optically pure lactic acid: a sustainable approach for Cassava-based agro-food industry waste" by Mr. DLA is one of the potentials. option that can be value added to cassava fibrous waste (CFW) generated in different stages.
Introduction and Review of Literature
Green Monomers
Cassava Current Scenario
- Cassava Production
- Cassava Utilization
- Economic Viability
- Value Addition
Such a strategy for the production of DLA from the large amount of fibrous cassava waste generated in the industry will not only be feasible but also a superior techno-economic business. Demands for cassava production have increased accordingly with population expansion and urbanization.
Biomass Waste Valorization
- Need
- Marketability and Competetiveness
- Socio Environment Impact and Acceptance
The marketability of cassava-based products will be highly dependent on the outstanding characteristics and quality of the final value-added product and on the extent to which it competes with other products made from other starchy raw materials (corn, sweet potato, rice grains, etc.). Marketability can be improved by monitoring the performance of the products and their impact on society.
D- Lactic Acid
- Market Demand and Stakeholders
- Feedstock Availability and Processing Difficulty
- Critical Process Parameters and Fermentation Barriers
- Purification Hurdles and Energy Accountability
- Existing Technology and Bioprocessing Strategies
Raw material is one of the major cost factors in the production of bulk chemicals such as DLA. Thus, the average size of well-defined starch particles in CFW was measured to be 9.4 μm. Also, the purification of lactic acid is one of the most crucial and costly steps in the entire production process.
Stubenrauch, Reactive extraction of lactic acid using tri-n-octylamine: structure of the ionic phase, Chem.
Research Gap
Conclusion
The decrease in the contact angle of the CCN matrix along with an increase in coating concentration was due to the improvement of the smoothness. A slight reduction in the relative activity of the immobilized nanofiber was observed for each recycling cycle. These results and their justifications are crucial for the interpretation of the subsequent DLA production kinetics.
An efficient method required as purification is one of the most expensive steps in the entire DLA production process.
Objectives
Parajó, Production of D(-)-lactic acid from cellulose by simultaneous saccharification and fermentation using Lactobacillus coryniformis subsp. Taniguchi, Production of D-lactic acid from defatted rice bran by simultaneous saccharification and fermentation, Bioresour.
Introduction
A steady increase in CFW shear resulted in a drastic reduction in viscosity, and a steep decrease was observed (Figure 2.5a) above a shear rate of 100 s-1. This improvement in smoothness was achieved by filling chitosan on the air pockets of the CCN matrix.
Materials and Methods
Chemicals
All chemicals are of analytical grade and are procured from Merck, India and Hi-Media, India. Analytical grade chloroform and N,N-dimethylformamide (DMF) used for polymer solution were purchased from Merck, India.
Feedstock processability analysis
All rheological analyzes were performed under fixed voltage and frequency sweep in the range from 0.1 to 500 Hz. Metal composition analysis was performed using an atomic absorption spectrophotometer (Spectra AA 220 FS, Varian, The Netherlands).
Preparation and characterization of CCN matrix
FESEM analysis of the nanofiber matrix was performed with a similar procedure mentioned as in section 2 of raw material processing. The water affinity of the chitosan-coated PLA nanofiber layer was identified by the water contact angle.
Immobilization of α - amylase onto CCN matrix for CFW hydrolysis
Free enzyme hydrolysis was performed by mixing 0.2 mg.ml-1 α-amylase solution in 1% (w/v) gelatinized starch mixed in 0.1 M sodium acetate buffer, and the mixture was incubated at 60°C for 36 hours . Similarly, hydrolysis using immobilized enzyme was carried out under similar conditions as in the case of hydrolysis of free enzyme, except that the free α-amylase solution was replaced by 50 mg.ml-1 α-amylase-immobilized CCN matrix .
Results
- Feedstock processability
- Characterization of Electrospun CCN matrix
- Immobilization of α - amylase onto CCN matrix and its use in CFW hydrolysis
The characteristic peak observed at 1638 cm-1 is due to the bound water molecule present in starch and the same explains the hydrophilic nature of starch. However, the relative activity was observed to be greater than 90% for all six reuse cycles performed in this study (Figure 2.11).
Discussion
Furthermore, the reduction in strain is an additional advantage as it allows the packing material to remain intact throughout the operation of the packed bed reactor. Sequentially, the reduced hydrophobicity and nanoproperties associated with the packing material are an additional advantage for the successful implementation of the current packing material in the pilot-scale packed bed reactor system.
Conclusion
As already mentioned in Section 3.2, the CCN matrix used in this study was adapted for viscous solution processing. The abundant availability of CFW and the ease associated with the automated production of the CCN matrix by the electrospinning process indicate the scalability of this study for the commercial production of fermentable sugars.
Cost-effective waste valorization of cassava fibrous waste into enantiomerically pure D-lactic acid: process engineering and kinetic modeling approach. The valorization of cassava fibrous waste (CFW) in the synthesis of D(-)lactic acid (DLA) is of enormous importance, especially for the production of thermostable biodegradable polymers.
Introduction
From Figure 3.4, the effect of inhibition can be understood by a constant decrease in µ above 20 gL-1. According to the result obtained in Section 3.3.1.1, the preliminary screening of HFLAB organisms identified Lactobacillus.
Materials and Methods
- Raw material
- Organism and culture conditions
- Production medium
- Screening of elite strain
- Screening of nitrogen source by OFAT approach
- Bioreactor experiments
- Analytical methods
- Kinetic modelling
- Biomass growth kinetics
- DLA production kinetics
- Substrate consumption kinetics
- Kinetic parameters estimation
Results
- Screening experiments
- Selection of elite strain and suitable carbon source
- Selection of nitrogen source and optimal concentration
- Kinetic modelling
The control run (without supplementing the nitrogen source) gave low DLA titer (7.05 gL-1), suggesting the importance of the role of nitrogen source selection in DLA production. The solved differential equations 3.4, 3.6 and 3.8 representing growth, DLA formation and CFWEH utilization were plotted with their respective offline values at different substrate concentrations of growth promoting (Figure 3.2) and inhibitory concentrations (Figure 3.3).
Discussion
- Growth kinetics
- Utilization of CFWEH
The death constant, kd, determined by simulation was 0.01 h-1 and insignificant compared to the higher growth rate. It was found that the specific rate of substrate utilization (1.54 gg-1h-1) is lower compared to other LAB species, i.e.
Conclusion
Sonomoto, Lactic acid production from lignocellulose-derived sugars using lactic acid bacteria: overview and limits, J. Aguirre-Ezkauriatza, a Ramírez-Medrano, a Rodríguez-Sánchez, Kinetic analysis and mathematical modeling of the growth and lactic acid production of Lactobacillus casei var .
Introduction
This present study focuses on improving the bioprocessing of DLA production by lactic acid bacteria (LAB), using hydrolyzate of CFW at laboratory scale fermentation process and subsequent kinetic modeling. Homo-fermentative lactic acid bacteria (HFLAB) are specialized genera that are characterized by strong D/L-lactate dehydrogenase activity and are able to metabolize any hexoses/pentoses more efficiently into lactic acid.
Materials and Methods
- Raw Materials and Enzymes
- Organism, storage and culture methods
- Process strategies
- Nitrogen source screening and optimization (Screw cap culture)
- Kinetic modeling of L. delbreuckii (Bioreactor operation)
- Static flask culture
- Bioreactor cultivation of L. debreuckii for DLA production
- Analytical Methods
- Microbial model elucidating L. delbreuckii growth
- Kinetic modeling – Procedure
Screening of the elite nitrogen source for DLA production was performed in autoclaved screw-capped tubes containing medium (100 mL) with CFWEH as the main carbon source (20 gL-1 conc.) supplemented with different nitrogen sources (25 gL-1 conc.), as shown in Table 4.1. A one-factor-at-time (OFAT) approach was used to elucidate the optimal concentration of the selected nitrogen source.
Results
- Preference of L. delbreuckii on different nitrogen sources
- Microbial growth and DLA production kinetics
By solving experimental data containing biomass, CFWEH and DLA concentrations for different initial substrate concentrations, Table 4.4 demonstrates the predicted kinetic parameters. Models included in Table 4.5 were tested for fit with the offline estimated μ values and inhibitory tendency was found (Figure 4.3) due to excess substrate and product inhibition.
Discussion
- Implications of different nitrogen sources in CFWEH fermentation
- L. delbreuckii growth-related kinetic parameters
- Inhibitory kinetics due to CFWEH supply and DLA productivity
Due to the mechanical nature of the model, the concluded μ values (in the h-1 range) were slightly higher than the real determination, i.e. the efficiency coefficient (𝑌𝑃 . ⁄𝑆) of each reactor plant (Table 4.6) contributes 85–95% of CFWEH and organic acid synthesis is likely to interfere with other household activities.
Conclusion
Execution of process flow based on the kinetic models on a laboratory scale provides knowledge about the design of the production process on a larger scale.
Comparitive assessment from Chapter 3 and Chapter 4: An observatory and concluding
Such operational limitations can be reduced by incorporating suitable buffering means into the medium. For this study, the model reliably predicts every parameter of the system and presents a comparison between both organisms.
Sivaprakasam, Improved production of optically pure D (–) lactic acid from nutrient rich Borassus flabellifer sugar and whey protein hydrolyzate based – fermentation medium, Biotechnol. Process intensification strategy for D lactic acid purification: A novel biocatalytic enzyme coupled with solvent technology and esterification.
Introduction
The key modification is to use different lipases derived from different organisms that show tolerance to organic solvents were used in the esterification reaction [18]. The use of solvent-stable lipase is unavoidable since a high concentration of organic solvents was used in the esterification reaction.
Materials and Methods
- Chemicals
- Enzyme catalyzed esterification by solvent engineering strategy for Methyl D-Lactate
The effect of different solvents used for lipase pretreatment was screened by using three different solvents viz. For lipase pretreatment, 50 mg of respective lipase enzymes were incubated in 100 μl of different solvents as mentioned previously.
Results
- Comparative performance of Immobilized enzyme and its activity
- Solvent engineering approach for enzymatic esterification
MDL ester production was investigated using Amano CL IM and Amano PS IM enzymes pretreated with hydrophobic and hydrophilic solvents. At the end of 18 h, Amano CL IM enzyme pretreated with tetrahydrofuran and methanol resulted in methyl D-lactate conversion efficiencies of 24.4% and 22.1%, respectively (Figure 5.1).
Discussion
A two-fold increase in the process efficiency with reactant diluted in an aqueous in comparison with the reactant diluted in water shows the extension of the present strategy to the actual fermentation broth containing DLA monomers. Thus, further studies are envisaged in the near future using the present Amano CL IM enzyme for esterification of real fermentation broth on a simultaneous reactive distillation setup.
Conclusion
Higher efficiency of the process with a slightly higher concentration of methanol is regularly observed in various literature dealing with biodiesel production. This can be attributed to the obvious reason of reducing the content of DLA – a key reactant in the reaction or its highlighting the threshold level of methanol tolerance for the Amano CL IM enzyme used in this study.
Huang, Production of high purity ethyl acetate using reactive distillation: An experimental and start-up procedure, Chem. Although many host organisms are available to produce DLA via the fermentation pathway, lactic acid bacteria (LAB) can be favored for natural lactic acid production.
