Lignocellulosic Mixtures Research Articles

Assessment of fed-batch strategies for enhanced cellulase production from a waste lignocellulosic mixture

Several problems are being encountered in the submerged fermentation (SMF) for cellulase production, globally. In this work, in a laboratory scale operation, three different fed-batch strategies were demonstrated to attempt circumventing the problems related to a batch SMF. The processes used novel surgical waste cotton and cardboard substrate mixture and a cellulolytic fungus Trichoderma harzanium ATCC® 20846™. FPase activities of: 1.94 ± 0.05 IU/mL, 2.12 ± 0.07 IU/mL, and 1.92 ± 0.2 IU/mL were obtained for the exponential feeding strategy; pulse feeding strategy, and pH stat, respectively. For all the three fed-batch SMFs, the biomass yield coefficients (Yx/s, Yx/O2); Oxygen Uptake Rates (OUR); maintenance coefficients (mO2, ms); mass transfer co-efficients (KLa); Oxygen Transfer Rates (OTR); and the effects of viscosity, sugar accumulation, and agitation on cellulase production; were estimated. Pulse feeding strategy yielded enhancements in enzyme activities than the other two feeding strategies. Basic financial analyses have been presented.

A study on cellulase production from a mixture of lignocellulosic wastes

The production of cellulase with enhanced enzyme activities has been a challenge for the biofuel industries. In this work, to prove the technical feasibility of using an alternate source of cellulose for cellulase production, a novel lignocellulosic mixture of waste surgical cotton and packaging cardboard, and a cellulolytic fungus Trichoderma harzanium ATCC® 20846™ were employed. After a 9 day Solid State Fermentation (SSF), FPase activities were, 2.405 IU/mL, 3.145 IU/mL, 3.230 IU/mL for untreated, dilute acid pre-treated, and ammonia pre-treated substrate mixtures, respectively. After a 120 -h Submerged Fermentation (SMF), the enzyme activities were: FPase 1.94 IU/mL, CMCase 12.47 IU/mL, beta Glucosidases 3165.4 IU/mL, and xylanases 756.6IU/mL. The biomass yield coefficients (Yx/s, Yx/O2); Oxygen Uptake Rate (OUR); maintenance coefficients (mO2); mass transfer coefficient (KLa); Oxygen Transfer Rate (OTR); the effects of viscosity and sugar accumulation, have been studied for the submerged fermentation process. A basic financial analysis has been presented.

Noodle waste based biorefinery: an approach to address fuel, waste management and sustainability

ABSTRACTNoodle waste contains significant amounts of starch, lignocellulosic material and oil. Pretreatment involving extraction followed by centrifugation is necessary to separate the oil from the starch and lignocellulosic mixtures. The isolated oil is subjected to a separation process to make it water and solvent free. Then, using esterification and transesterification reactions, the oil is converted to biodiesel by chemical (97.8–98.5% yield) and enzymatic (95.4% yield) methods. The residual starch and lignocellosic mixtures are hydrolyzed enzymatically to form small sugar units, such as glucose and fructose. The obtained hydrolysate is then fermented to produce bioethanol (conversion rate 96.8%). The hydrolysate can also be used as a nutrient for growing microorganisms for the production of lipids, enzymes and pigments. Additionally, noodle waste can be converted to animal feed.

Mixed Lignocellulosic Biomass Degradation and Utilization for Bacterial Cellulase Production

Feedstock supply challenges provide impetus into the exploration of lignocellulosic mixtures in bioprocessing. Such mixtures have not been fully explored for bacterial cellulase production. Four bacterial species were evaluated for ability to utilize a mixture of oil palm and rice residues (MS) for cellulase production. Bacillus aerius, Bacillus anthracis, Cellvibrio japonicus and Klebsiella pneumoniae with ability to utilize MS for growth were investigated. A two-step sequential strategy was employed in selecting the candidate for cellulase production and degradation of MS. B. aerius displayed better cellulolytic ability than the others during plate screening on carboxymethyl cellulose-enriched medium. However, C. japonicus produced the highest activities of endoglucanase and total cellulase during targeted screening on MS. Analyses revealed that sequential pretreatment with NaOH and moist heat increased the accessibility and disrupted the surface morphology of MS for subsequent bacterial utilisation. C. japonicus achieved significant degradation of MS with 52.33 % substrate dry weight loss after 7 days as compared to B. aerius which degraded 21.33 % of MS in the same period. Substrate was hydrolyzed via the amorphous region. The low residual concentration of reducing sugars in the medium suggested that C. japonicus converted the liberated sugars into other products.

Hydrothermal pretreatment of several lignocellulosic mixtures containing wheat straw and two hardwood residues available in Southern Europe

This work studied the processing of biomass mixtures containing three lignocellulosic materials largely available in Southern Europe, eucalyptus residues (ER), wheat straw (WS) and olive tree pruning (OP). The mixtures were chemically characterized, and their pretreatment, by autohydrolysis, evaluated within a severity factor (logR0) ranging from 1.73 up to 4.24. A simple modeling strategy was used to optimize the autohydrolysis conditions based on the chemical characterization of the liquid fraction. The solid fraction was characterized to quantify the polysaccharide and lignin content. The pretreatment conditions for maximal saccharides recovery in the liquid fraction were at a severity range (logR0) of 3.65–3.72, independently of the mixture tested, which suggests that autohydrolysis can effectively process mixtures of lignocellulosic materials for further biochemical conversion processes.

Assessment of degradation potential of aliphatic hydrocarbons by autochthonous filamentous fungi from a historically polluted clay soil

The present work was aimed at isolating and identifying the main members of the mycobiota of a clay soil historically contaminated by mid- and long-chain aliphatic hydrocarbons (AH) and to subsequently assess their hydrocarbon-degrading ability. All the isolates were Ascomycetes and, among them, the most interesting was Pseudoallescheria sp. 18A, which displayed both the ability to use AH as the sole carbon source and to profusely colonize a wheat straw:poplar wood chip (70:30, w/w) lignocellulosic mixture (LM) selected as the amendment for subsequent soil remediation microcosms. After a 60d mycoaugmentation with Pseudoallescheria sp. of the aforementioned soil, mixed with the sterile LM (5:1 mass ratio), a 79.7% AH reduction and a significant detoxification, inferred by a drop in mortality of Folsomia candida from 90 to 24%, were observed. However, similar degradation and detoxification outcomes were found in the non-inoculated incubation control soil that had been amended with the sterile LM. This was due to the biostimulation exerted by the amendment on the resident microbiota, fungi in particular, the activity and density of which were low, instead, in the non-amended incubation control soil.

Selective Signal Detection in Solid-State NMR Using Rotor-Synchronized Dipolar Dephasing for the Analysis of Hemicellulose in Lignocellulosic Biomass

Solid-state dipolar dephasing filtered (DDF)-INADEQUATE experiments were used to detect the hemicellulosic signals of lignocellulosic mixtures; here dipolar dephasing was used as a signal filter to...

Mechanical and Physical Properties of Cement-Bonded Perticleboard Made from Tea Residues and Hardboards

The residues of tea factory and waste hardboards are generally incinerated without utilizing their heat performances. The first objective of this study was to manufacture cement bonded particleboard using residues of tea factory (Camellia sinenses L.) and waste hardboards. The second objective was to evaluate modulus of rupture (MOR), modulus of elasticity (MOE), internal bonding strength (IB), water absorption (WA) and thickness swelling (TS) properties of the boards produced. The boards were produced at two density levels of 800 and 1200 kg/m3 and at five lignocellulosic mixture ratios of poplar chips/hardboards/tea residues (1/0/0; 1/1/0; 1/0/1; 0/1/0; 0/0/1, based on weigth). All the boards were produced at lignocellulosic material/cement ratio of 1:2.75 on a weight to weight basis. As cement curing accelerators, Al2(SO4)3 and Na2SiO3 were used at ratios of 1.5% and 3.5%, based on cement weight, respectively. The MOR values ranged from 0.8 to 10.99 MPa and MOE values ranged from 254 to 2979 MPa. The mean values of WA and TS after 24 h of water soaking of the cemen bonded particleboards ranged from 28% to 43.5% and 1.3% to 8.08%, respectively.