Low Moisture Anhydrous Ammonia Pretreatment of Four Lignocellulosic Materials—Distillers Dried Grains With Solubles, Corn Gluten Feed, Corn Fiber, and Oil Palm Frond

Lignin and hemicellulose structures in cellulosic materials serve as a barrier for enzyme reactions. A pretreatment step is often needed to break these components to allow the biomass to be utilized as a source of value-added products. Various available pretreatment methods possess common drawbacks of the high amount of liquid and chemical requirements, harsh process conditions, and the high amount of waste produced, which driving up the production costs of bioproducts. Low moisture anhydrous ammonia (LMAA) pretreatment capable of eliminating those drawbacks. In this study, Distillers Dried Grains with Solubles (DDGS), corn gluten feed (CGF), corn fiber (CF), and oil palm frond (OPF) with different moisture contents were subjected to LMAA pretreatment at the specific ammonia loading rate, 1 h ammoniation, and 75°C incubation temperature. This pretreatment successfully decreased the lignin content of the materials, increased their percentage of α-cellulose, and improved enzymatic digestibility for most of the materials tested. The effect of moisture content (30 and 50% db) was found to be more significant than that of incubation time (24 and 72 h)

Low moisture anhydrous ammonia (LMAA) pretreatment of lignocellulosic biomass and assessments for biobutanol production

Low-value biomass materials such as processing co-products and agricultural wastes possess abundant potential in value-added products production. The effort for utilization of these materials, especially as the substrate for fermentation process was limited by the low availability of fermentable sugar. This is due to the presence of lignin and hemicellulose in biomass structure, which entails appropriate pretreatment procedure to be conducted to expose the cellulose for the enzymatic reaction. Alkali-based pretreatments offer the attractive benefit of low inhibitor compound production. In this study, low moisture anhydrous ammonia (LMAA) pretreatment was conducted on selected biomass. Anhydrous ammonia, which is a gaseous state pretreatment agent, is naturally evaporated from the biomass after the process, therefore, have considerable potential to be recycled. Selected materials were Distillers Dried Grains with Solubles (DDGS), corn gluten feed (CGF), and corn fiber (CF) from corn processing industries and oil palm frond (OPF) from oil palm plantation site. These materials are either sold at a relatively low price or with no value at all. The study was conducted using raw materials at different moisture contents (30 % and 50 % db.) and several incubation periods (24, and 72 h). The changes in the percentages of lignin, α-cellulose, and hemicellulose in each biomass along with the changes enzymatic digestibilities percentages were assessed. There was no significant difference in the results for most of the cases between materials incubated at 24 h with those incubated for 72 h. For the moisture content (MC) effect, higher MC (50 %) CGF and CF gave significantly higher percentages of α-cellulose than those of 30 % MC, while the case was vice versa for DDGS and OPF. The compositional results were compared to the enzymatic digestibilities results to determine the best LMAA operating conditions. The results suggest that LMAA-treated DDGS, CGF, and CF could be additional feedstocks for the ethanol fermentation process. Other than fermentation into ethanol, glucose obtained from the hydrolysate of treated biomass is also a suitable substrate for butanol production or other fermentation-based products (i.e., biochemical). Works on cellulosic butanol production from a variety of raw materials are still lacking. Therefore, this study also attempts to assess the potential of LMAA-treated biomass for butanol production. OPF was used as the model substrate for all SuperPro Designer simulation works. Economies of scale effect have shown that acetone-butanol-ethanol (ABE) fermentation plant at 95.34 × 106 L butanol/y size gave the minimum butanol production cost ($2.05/L). The major operating expenditures (OpEx) contributor was utilities (41$ 1.63/L. In the next part of the study, improvements on the models were applied, which includes the application of the CHP system to supply the heat and power for the entire plant and on-site cooling water generation. The simulation also conducted using different pretreatment (LMAA, autohydrolysis, SAA, and NaOH) and products separation (in-situ stripping, adsorption, pervaporation, and dual extraction) approaches. The results have shown that among all pretreatment tested, NaOH pretreatment gave the best yield, while the best yield among all products separation techniques was given by adsorption process. Nevertheless, the lowest butanol production cost of $ 1.58/L was recorded from the combination of LMAA pretreatment and in-situ stripping process. In several of the chosen models, by considering xylose content and its potential in butanol production, further reduction of butanol production costs was recorded with promising profit generated. The final part of the study focused on the environmental impacts of all plant models simulated. The assessed impacts were global warming potential (GWP), ecotoxicity potential, and eutrophication potential. SAA pretreatment and pervaporation process recorded among the lowest GWP. LMAA in combination with in-situ stripping process recorded net energy value (NEV), net energy ratio (NER), and fossil energy ratio (FER) in the middle range among all other models simulated. The fact that these values were neither the lowest nor the highest might indicate that LMAA pretreatment possesses a potential for more detail study and commercialization. Techno-economic analysis and life-cycle assessment are necessary to determine the feasibility and sustainability of butanol production from cellulosic co-products and waste materials. The data is useful for further development effort of the processes

Life-Cycle Assessment (LCA) of Different Pretreatment and Product Separation Technologies for Butanol Bioprocessing from Oil Palm Frond

Environmental impact assessment is a crucial aspect of biofuels production to ensure that the process generates emissions within the designated limits. In typical cellulosic biofuel production process, the pretreatment and downstream processing stages were reported to require a high amount of chemicals and energy, thus generating high emissions. Cellulosic butanol production while using low moisture anhydrous ammonia (LMAA) pretreatment was expected to have a low chemical, water, and energy footprint, especially when the process was combined with more efficient downstream processing technologies. In this study, the quantification of environmental impact potentials from cellulosic butanol production plants was conducted with modeled different pretreatment and product separation approaches. The results have shown that LMAA pretreatment possessed a potential for commercialization by having low energy requirements when compared to the other modeled pretreatments. With high safety measures that reduce the possibility of anhydrous ammonia leaking to the air, LMAA pretreatment resulted in GWP of 5.72 kg CO2 eq./L butanol, ecotoxicity potential of 2.84 × 10−6 CTU eco/L butanol, and eutrophication potential of 0.011 kg N eq./L butanol. The lowest energy requirement in biobutanol production (19.43 MJ/L), as well as better life-cycle energy metrics performances (NEV of 24.69 MJ/L and NER of 2.27) and environmental impacts potentials (GWP of 3.92 kg N eq./L butanol and ecotoxicity potential of 2.14 × 10−4 CTU eco/L butanol), were recorded when the LMAA pretreatment was combined with the membrane pervaporation process in the product separation stage

Techno-Economic Analysis (TEA) of Different Pretreatment and Product Separation Technologies for Cellulosic Butanol Production from Oil Palm Frond

Among the driving factors for the high production cost of cellulosic butanol lies the pretreatment and product separation sections, which often demand high amounts of energy, chemicals, and water. In this study, techno-economic analysis of several pretreatments and product separation technologies were conducted and compared. Among the pretreatment technologies evaluated, low-moisture anhydrous ammonia (LMAA) pretreatment has shown notable potential with a pretreatment cost of $0.16/L butanol. Other pretreatment technologies evaluated were autohydrolysis, soaking in aqueous ammonia (SAA), and soaking in sodium hydroxide solution (NaOH) with pretreatment costs of$1.98/L, $3.77/L, and$0.61/L, respectively. Evaluation of different product separation technologies for acetone-butanol-ethanol (ABE) fermentation process have shown that in situ stripping has the lowest separation cost, which was $0.21/L. Other product separation technologies tested were dual extraction, adsorption, and membrane pervaporation, with the separation costs of$0.38/L, $2.25/L, and$0.45/L, respectively. The evaluations have shown that production of cellulosic butanol using combined LMAA pretreatment and in situ stripping or with dual extraction recorded among the lowest butanol production cost. However, dual extraction model has a total solvent productivity of approximately 6% higher than those of in situ stripping model

Low Metal Loading Palladium Mixed-Oxides Catalyst for the Synthesis of Glycerol Carbonate

Glycerol carbonate can be readily synthesized from glycerol and urea catalyzed by PdZnO, PdSnO2, SnO2, and ZnO. The superior catalytic activity of ZnO over SnO2 is mainly due to basicity property. The incorporation of low metal loading of Pd on both SnO2 and ZnO produced higher yield of glycerol carbonate to bulk material counterpart. In addition, the sol-gel technique was shown to have higher turn-over frequency (TOF) due to highly disperse Pd with small crystallite size

Optimisation of solid liquid extraction of Orthosiphon stamineus leaves using response surface methodology technique

Orthosiphon stamineus is one of the popular medicinal plants in Southeast Asia. O. stamineus leaves are used in numerous applications related to medicinal purposes and are believed to cure certain health conditions such as hypertension, gout and fever. The aim of this study was to investigate the effect of three parameters involved in extraction process including extraction temperature, extraction duration and solvent to solid ratio on extraction yield, antioxidant activity and referral markers of O. stamineus leaves. The optimisation of extraction processes was evaluated with the aid of Design-Expert software using response surface methodology (RSM). The optimum extraction parameter for O. stamineus leaves were recorded at the extraction temperature of 60°C, 30:1 (ml:g) solvent to solid ratio and 6 hours extraction duration with 30Wt% extract, 67 and 1 mg/L concentration of Rosmarinic acid and Sinensetin, respectively. Antioxidant activity for optimized extract is 96.56% and 91.51% of SOD and DPPH method, respectively

Watermelon waste as a growth media substitute for bacterial cellulose production

Local fruits in Malaysia include tropical fruits that are rich in sugars. This includes watermelon which is grown largely on the east coast of Malaysia. However, due to reasons such as unpredictable weather changes, as well as the poor practice of harvesting and storage, a large portion of this fruit ends up rotten and dumped. The use of this fruit waste as a growth medium for bacterial cellulose production is seen as an excellent way to utilize it, in addition to encouraging the production of low-cost bacterial cellulose. Watermelon waste contains approximately 7 % sugars, a trace amount of protein and lipid, and the rest is moisture content. The treated watermelon waste from selected parameters was used in the fermentation of bacterial cellulose using Gluconacetobacter xylinus in an inoculum concentration of 8 and 10 %. The produced bacterial cellulose was quantified, analysed and compared to those using synthetic media. The moisture content, total solid, volatile solid, and fixed solid of watermelon were investigated which its recorded 97.45 %, 2.55 %, 2.18 %, and 0.76 % respectively. The carbohydrate content for treated watermelon was analysed by using phenol-sulphuric acid method, which the highest carbohydrate present was at 100 ℃ with watermelon waste to water ratio of 1:2, and 90 minutes incubation time. The BC pellicle’s produced was determined based on its BC yield, thickness, carbohydrate concentration before and after 16 days fermentation, and FTIR-ATR. The highest BC yield recorded was 1.0 cm (5.8090 mg/mL), which was cultured in treated watermelon waste only at 10 % inoculum density

Whole genome sequencing analysis of Komagataeibacter nataicola reveals its potential in food waste valorisation for cellulose production

Background: Komagataeibacter nataicola (K. nataicola) is a gram-negative acetic acid bacterium that produces natural bacterial cellulose (BC) as a fermentation product under acidic conditions. The goal of this work was to study the complete genome of K. nataicola and gain insight into the functional genes in K. nataicola that are responsible for BC synthesis in acidic environments. Methods and result; The pure culture of K. nataicola was obtained from yeast-glucose-calcium carbonate (YGC) agar, followed by genomic DNA extraction, and subjected to whole genome sequencing on a Nanopore flongle flow cell. The genome of K. nataicola consists of a 3,767,936 bp chromosome with six contigs and 4,557 protein coding sequences. The maximum likelihood phylogenetic tree and average nucleotide identity analysis confirmed that the bacterial isolate was K. nataicola. The gene annotation via RAST server discovered the presence of cellulose synthase, along with three genes associated with lactate utilization and eight genes involved in lactate fermentation that could potentially contribute to the increase in acid concentration during BC synthesis. Conclusion: A more comprehensive genome study of K. nataicola may shed light into biological pathway in BC productivity as well as benefit the analysis of metabolites generated and understanding of biological and chemical interactions in BC production later

Preliminary assessment on pretreatment methods for landfill waste utilization in biohydrogen production

Landfill waste consists of a mixture of components that have high potential as a substrate for hosting various microorganisms’ growth. Utilizing this waste as a fermentation substrate is seen as an economical solution for the management of the waste. Treating this waste is crucial to remove unnecessary components for the growth of specific organisms to ensure a high reaction yield. Fermentative hydrogen production from this waste specifically requires the hydrogen-consuming bacteria to be reduced. In this work, heat, ultraviolet (UV) radiation, acid, and alkaline pretreatment were conducted on the landfill waste. The changes in the reduced sugar content and appearance of bacterial colonies were observed and compared. Heat pretreatment at 65 °C was found to give among the best increase (74 – 88%) in reducing sugar content and reduction (50 – 85%) in the number of aerobic bacterial colonies detected. Global warming potential and eutrophication potential recorded from simulated heat pretreatment plant was comparable to other heat-based pretreatment reported by other researchers with a potential reduction in severity as the plant size increased