Inexpensive Agricultural By-product Research Articles

Sustainable packaging biocomposites from polylactic acid and wheat straw: Enhanced physical performance by solid state shear milling process

As a sustainable and inexpensive agricultural byproduct, wheat straw has gained major interest as filler in green composites in recent years, but previous studies about PLA/wheat straw composites have reported modest enhancement or even major reduction in physical performance. Here, we report a new method for both production cellulose nanofibrils and achieving excellent dispersion in composites free of solvent for the first time, and enhanced physical performance is obtained via solid state shear milling process (SSSM). The SSSM pretreatment process led wheat straw an ultrafine particle size and even the separation of cellulose nanofibrils from micro-sized pristine cellulose fibers. Both optical and electron microscopy revealed that composites made by SSSM process exhibit excellent dispersion of hemicellulose, lignin and cellulose nanofibrils which derived from wheat straw. Such PLA/wheat straw composites exhibited fast crystallization rate with 0.8 min crystallization half-time and 41.4% crystallinity, leading major enhancement in flexural modulus which exceed the known value reported in the literature. In addition, a heat deflection temperature of 73 °C is observed with 30%wt wheat straw, which is much higher than neat PLA. Furthermore, high water vapor permeability is observed in composites, enabling food packaging applications especially for respiring fresh products such as fruits and vegetable. The approach presented in this paper highlights a novel technique for recovering wheat straw in producing value-added products.

Enzymatic in situ saccharification of sugarcane bagasse pretreated with low loading of alkalic salts Na2SO3/Na3PO4 by autoclaving

Sugarcane bagasse (SCB) is an abundant, renewable and inexpensive agricultural byproduct for the production of biofuel and other biobased products. To effectively saccharify SCB with cellulases, combination with dilute alkali salts Na2SO3/Na3PO4 (0.4% Na3PO4, 0.03% Na2SO3) at 7.5% sulfidity and hot water (DASHW) in “one-pot” pretreatment media by autoclaving at 110°C for 40min was attempted to pretreat SCB in this study. Furthermore, FT-IR, XRD and SEM were employed to characterize the changes in the cellulose structural characteristics (porosity, morphology, and crystallinity) of the pretreated Na2SO3/Na3PO4-SCB solid residue, which indicated that combination pretreatment could effectively remove lignin and hemicellulose for enhancing enzymatic saccharification. After 72h, the reducing sugars and glucose from the enzymatic in situ hydrolysis of 50g/L Na2SO3/Na3PO4-SCB in dilute Na2SO3/Na3PO4 (0.27% Na3PO4, 0.02% Na2SO3) media were obtained at 33.8 and 21.8g/L, respectively. Finally, the SCB-hydrolysates containing 20g/L glucose were used for ethanol fermentation in the presence of dilute alkali salts. After 48h, the ethanol yield was 0.42g ethanol/g glucose, which represents 82.1% of the theoretical yield. In conclusion, this study provided an effective pretreatment strategy for enhancing SCB’s saccharification, which has potential application of other lignocellulosic materials.

Optimization of Inexpensive Agricultural By-Products as Raw Materials for Bacitracin Production in Bacillus licheniformis DW2.

Bacitracin is a broad-spectrum antibiotic used extensively as a feed additive. In this study, inexpensive agricultural by-products were used as nitrogen sources for bacitracin production. Based on both the orthogonal tests, a combination of 7% soybean meal (SBM) +2% low protein rapeseed cake (LPRC) was optimal for bacitracin production. Compared to the original formula, the titer of bacitracin increased by 20.5% reaching 910.4U/ml in flasks. The titer of bacitracin and the ratio of bacitracin A increased by 12.4 and 6.8% in a 50-l fermentor. Furthermore, this study also explored the effects of exogenously adding different amino acids on the yield of bacitracin. The addition of Cys and Glu enhanced bacitracin production by 5.7 and 5.0%, respectively. This study provided the inexpensive nutrient inputs into efficient bacitracin production and also the insight to further research enabling better utilization of oil cakes for economic viability of the bioprocess industry.

Use of solid digestate for lignocellulolytic enzymes production through submerged fungal fermentation

Studies were performed on the use of the solid fraction of digestate (D) for the production of lignocellulolytic enzymes (endo- and exo-glucanase, xylanase, β-glucosidase and laccase) by fungi, in comparison with wheat straw (benchmark) (W). To date, this is the first report on the use of such an inexpensive substrate in a liquid environment. Submerged instead of solid state fermentation was applied to overcome pH inhibition and increase surface accessibility. A total of 21 fungal strains were tested: the most performing ones were Irpex lacteus DSM1183 for both β-glucosidase (52 IU/g with D, + 400% compared to W) and endo-glucanase (236 IU/g with D, + 470% compared to W), Schizophyllum commune CBS30132 for xylanase (715 IU/g with W, + 145% compared to D) and Pleurotus ostreatus ATCC96997 for laccase (124 IU/g with D, +230% compared to D).Cultures from S. commune and P. ostreatus were analyzed at the beginning and at the end of the growth test to determine soluble COD, total (TS) and volatile (VS) solids. COD was always lower at the end of the test suggesting a faster uptake than hydrolysis. P. ostreatus evidenced a higher VS reduction (−11% rather than −32%), suggesting a more effective growth of this strain on D.Results may open up new avenues for the utilization of solid digestate, an inexpensive agricultural by-product, for the production of value-added products as well as to increase biodegradation of lignocellulosic materials.

Full replacement of menhaden fish meal protein by low-gossypol cottonseed flour protein in the diet of juvenile black sea bass Centropristis striata

Eight isonitrogenous (46% crude protein) and isolipidic (14% crude lipid) diets were formulated for juvenile black sea bass Centropristis striata to replace menhaden fish meal (FM) protein (59.5% CP) by three cottonseed meal (CSM) proteins: a CSM prepared from glandless seed (GCSM, 50.4% CP), a CSM that had been solvent extracted with acidic ethanol to remove the gossypol (SCSM, 53.8% CP), and a CSM prepared from regular (glanded) cottonseed (RCSM, 45% CP). Three diets replaced 50, 75 and 100% of FM protein with GCSM, and three diets replaced 50, 75 and 100% of FM protein with SCSM. One diet replaced 100% FM protein with RCSM protein. A control diet (0% CSM) was formulated with high FM protein and other practical protein sources. l-methionine and l-lysine were supplemented to the diets to equal the control diet. Fifteen fish were stocked in each of twenty-four 75-L tanks, and each test diet was fed to triplicate groups of fish (mean initial weight=7.7±0.10g) for 56days at 22–24°C, 32–35 salinity, and ambient photoperiod conditions. Fish were fed twice per day to apparent satiation. Final (day 56) mean body weight (BW, 24.16–31.62g), body weight gain (BWG, 211.2–311.3%), specific growth rate (SGR, 1.70–2.18%/d), and feed intake (FI, 0.37–0.43g/fish/d) were not significantly different (P>0.05) among the control, GCSM or SCSM treatments, but were reduced (P<0.05) for the 100% RCSM treatment (20.09g, 159.5%, 1.45%/d, and 0.25g/fish/d, respectively). Lower palatability of the RCSM diet was attributable to the anti-nutrient compound gossypol. No significant differences in survival (84.1–97.8%), feed conversion ratio (FCR, 1.05–1.33), protein efficiency ratio (PER, 1.62–2.08), or whole body protein or lipid composition were observed among the fish fed the low-gossypol diets. Gossypol (25.9mg/kg) was only detectable in the livers of fish fed the high-gossypol RCSM diet. Fish whole body essential amino acid compositions did not differ significantly among treatments. Whole body n − 3 PUFAs decreased, while n−6 PUFAs increased with increasing CSM protein in the diets. The apparent digestibility coefficient of protein was high (83.1–87.1%) for all treatments. For juvenile black sea bass, 75% FM in the diet can be replaced with low-gossypol CSM protein prepared by solvent-extraction, and 100% of FM can be replaced with low-gossypol CSM protein prepared from glandless seed with no adverse effects on survival, growth or feed utilization. Statement of relevanceCotton seed flour is an inexpensive agricultural by-product. The results demonstrate successful replacement of fish meal protein with genetically-improved cottonseed flour protein in the diet of black sea bass. These findings may substantially lower aquafeed costs (a key operational cost) for finfish growout operations to boost profitability and accelerate expansion of commercial production of black sea bass and other finfish species.

The Potential of Date-palm Leaf Ash as Low-cost Adsorbent for the Removal of Pb(II) Ion from Aqueous Solution

This study investigated the feasibility of Date-palm) Phoenix dactylifera (Leaf Ash (DLA) (an inexpensive agricultural-byproduct) as an application to adsorb Pb(II) ions. An adsorption process was carried out to evaluate initial concentration Pb(II) ions, adsorbent dose, contact time, pH and temperature on the systematic removal of Pb(II). The effects were examined and results showed that removal efficiency decreased with an increase of initial Pb(II) concentration and optimum removal efficiency of 99.72% was at 50 mg/l Pb(II) solution, 0.5 g/l DLA dose and pH level of 5. The results showed that with increased dose of adsorbent dose, Pb(II) adsorption also increased. The equilibrium data were analyzed using the Langmuir and Freundlich isotherm models by nonlinear regression analysis at 20, 30 and 40 ˚C. It was found that the Langmuir isotherm model fitted better than the Freundlich isotherm model. However, the kinetic adsorption of Pb(II) ions was tried using three kinetic models, the pseudo-first-order, the pseudo-second-order and the intra-particle diffusion model and these tests demonstrated that the overall adsorption process was the one most suited to the pseudo-second-order kinetic model. Thermodynamic parameters, Gibbs free energy (∆G˚), enthalpy (∆H˚), and entropy (∆S˚) were also evaluated, with application of the van’t Hoff equation that describes the dependence of equilibrium constant on temperature. Final evaluation of the thermodynamics of Pb(II) adsorption onto DLA demonstrated that adsorption was spontaneous and endothermic.

On-farm evaluation of the effect of coffee pulp supplementation on milk yield and dry matter intake of dairy cows grazing tropical grasses in central Mexico

Tropical grasses are the primary nutrient resource for cattle production in the tropics, and they provide low-cost nutrients to cattle. However, its production is constrained by seasonal changes and quality; hence, appropriate usage of relatively inexpensive agricultural by-products is important to profitable livestock production. The objective of the study was to evaluate the effect of supplementing coffee pulp to dairy cows grazing tropical grasses on milk yield and forage intake. Four multiparous crossed Holstein-Brown Swiss-Zebu cows of similar weight and milk yield were used. The effect of 10%, 15% and 20% inclusion of coffee pulp in dairy concentrates on milk yield and forage intake was analysed using a 4 × 4 Latin square design. Results showed that there were no significant effects (P > 0.05) in grass dry matter intake, milk yield, milk composition body weight and body condition score due to the inclusion of coffee pulp in the dairy concentrates. It is concluded that coffee pulp can be included at levels of 20% in the concentrate without compromising significantly (P > 0.05) milk yield, milk composition and grass dry matter intake. It also was concluded that cost of concentrate is reduced in 20% by the inclusion of coffee pulp.

Overproduction of laccase by a monokaryotic strain of Pycnoporus cinnabarinus using ethanol as inducer

Laccase production by the monokaryotic strain Pycnoporus cinnabarinus ss3 was studied using ethanol as inducer in the culture medium. The effect of ethanol was tested at 10, 20, 30, 35 and 45 g l-1 and compared with that of ferulic acid, known until now as the most efficient inducer for laccase expression by P. cinnabarinus ss3. In the presence of 35 g l-1 ethanol, laccase activity (266 600 U l-1) and productivity (19 000 U l-1 day-1) were nine and fivefold higher compared with ferulic acid-induced cultures, and 155- and 65-fold higher compared with non-induced cultures, respectively. In vivo, ethanol added to the culture medium of P. cinnabarinus ss3 favoured a continuous and high expression of laccase gene. Under these conditions, P. cinnabarinus ss3 produced preferentially the isoenzyme LAC I. Ethanol added in vitro to the purified P. cinnabarinus ss3 laccase typically inhibited the enzymatic activity. In spite of an initial inhibitory effect on mycelial growth, ethanol was shown to be a very strong inducer for laccase expression by P. cinnabarinus ss3 allowing an average yield of 1-1.5 g l-1 laccase. This study identified P. cinnabarinus ss3 as an outstanding producer of laccase in the presence of ethanol as inducer. Ethanol is an inexpensive agricultural by-product and the process is simple to scale-up for industrial production.