Highest Bioconversion Efficiency Research Articles

The Efficiency of Black Soldier Fly Larvae with Vegetable, Fruit and Food Waste as Biological Tool for Sustainable Management of Organic Waste

This study investigated the sustainable management of wet organic waste using Black Soldier Fly Larvae (BSFL) for an innovative biological approach to waste management. The organic wet wastes such as fruit, vegetable, and food wastes were processed and fed to BSFL larvae from day 5 and the bioconversion process was carried out at Black Soldier Fly Unit, Tamil Nadu Agricultural University for 21 days. Among the three wastes, the highest bioconversion efficiency was recorded in fruit waste with 67% Substrate Reduction, 10.8% Efficiency of Conversion of Digested feed, 5.7% Bio Conversion Rate, and 4.18 Waste Reduction Index after 21 days. Whereas vegetable and food waste achieved similar bioconversion efficiency. The results suggest that BSFL-based bioconversion can be an effective and eco-friendly waste management and resource recovery technique to significantly lower the volumes of organic wet waste while converting it into high-value biomass and leading to a circular economy model.

Use of fermented spent coffee grounds as a substrate supplement for rearing black soldier fly larvae, Hermetia illucens (L), (Diptera: Stratiomyidae).

Spent coffee grounds (SCG), an increasingly abundant waste product with environmental disposal problems, has been used as a dietary supplement for many animals and have the potential to be used as a dietary supplement for black soldier fly (BSF) larvae; however, its effective use is still under scrutiny. To date, no studies have considered the use of SCG after microbial fermentation (fSCG) and its effects on BSF life history. A mixture of fruit and vegetable pulp residue supplemented with one of six different fSCG percentages (0%, 20%, 40%, 60%, 80%, and 100% by weight) were provided as a diet substrate in order to evaluate the effect of the fSCG quantity on BSF growth, yield, and conversion ability. The addition of fSCG to the pulp diet prolonged larval development times, while 100% fSCG affected the larval survival rate and resulted in a male-biased adult sex ratio. The 20-40% fSCG and 40-60% fSCG treatments supported the largest prepupal and mature larval sizes, respectively. The highest waste reduction efficiency and feed conversion rate by BSF larvae was found with 20% fSCG, similar to the control (0% fSCG). From the short rearing time, high yield, and high bioconversion efficiency, a 20% fSCG supplementation of the mixed pulp was recommended for rearing BSF larvae. These data are valuable for coffee by-product waste management in urban areas.

The physical structure of compost and C and N utilization during composting and mushroom growth in Agaricus bisporus cultivation with rice, wheat, and reed straw-based composts.

The cultivation of Agaricus bisporus with compost made from wheat (Triticum aestivum L.), rice (Oryza sativa L.), and reed (Phragmites australis Trin.) straw was investigated. Straw degradation was analyzed at the microscopic level, and the corresponding changes in the breakdown of different lignocellulose components during different phases of composting and mushroom production helped in understanding the yield-limiting factors of using different straws to grow mushrooms. The wheat straw compost resulted in the highest mushroom production and had the highest bioconversion efficiency. The rice straw was limited by the softer texture, which resulted in low-porosity and overdecomposed compost in the composting process and decreased the amount of available lignocellulose during mycelial growth. Although reed straw had the largest carbon resources, its utilization rate was the lowest. The hard structure, low water holding capacity, and high porosity increased the recalcitrance of reed straw to degradation and prolonged the composting time, which resulted in large N and C losses and an increased C/N ratio. Moreover, reed straw failed to transform into "ready-to-consume C" in composting. Therefore, a high C/N ratio and deficiency of available nutrition decreased the utilization efficiency of the lignocellulosic components by A. bisporus during mycelial colonization and mushroom production. The investigation revealed that degradability by and availability to microbiota and A. bisporus seemed to be the overriding factors for optimizing the composting process with different straw types. KEY POINTS: • The physical structure of compost has a significant influence on the composting process. • Degradability and availability are key factors in compost quality evaluation. • Lignocellulose utilization efficiency positively correlated with mushroom yield.

Enzymatic response of ryegrass cellulose and hemicellulose valorization introduced by sequential alkaline extractions

BackgroundIn view of the natural resistance of hemicelluloses in lignocellulosic biomass on bioconversion of cellulose into fermentable sugars, alkali extraction is considered as an effective method for gradually fractionating hemicelluloses and increasing the bioconversion efficiency of cellulose. In the present study, sequential alkaline extractions were performed on the delignified ryegrass material to achieve high bioconversion efficiency of cellulose and comprehensively investigated the structural features of hemicellulosic fractions for further applications.ResultsSequential alkaline extractions removed hemicelluloses from cellulose-rich substrates and degraded part of amorphous cellulose, reducing yields of cellulose-rich substrates from 73.0 to 27.7% and increasing crystallinity indexes from 31.7 to 41.0%. Alkaline extraction enhanced bioconversion of cellulose by removal of hemicelluloses and swelling of cellulose, increasing of enzymatic hydrolysis from 72.3 to 95.3%. In addition, alkaline extraction gradually fractionated hemicelluloses into six fractions, containing arabinoxylans as the main polysaccharides and part of β-glucans. Simultaneously, increasing of alkaline concentration degraded hemicellulosic polysaccharides, which resulted in a decreasing their molecular weights from 67,510 to 50,720 g/mol.ConclusionsThe present study demonstrated that the sequential alkaline extraction conditions had significant effects on the enzymatic hydrolysis efficiency of cellulose and the investigation of the physicochemical properties of hemicellulose. Overall, the investigation the enzymatic hydrolysis efficiency of cellulose-rich substrates and the structural features of hemicelluloses from ryegrass will provide useful information for the efficient utilization of cellulose and hemicelluloses in biorefineries.

English

Mushroom production is an economically viable biotechnology process for conversion of various agro-industrial wastes into food. Mushroom, a fruiting body of macrofungi has been valued throughout the world as either food or medicine for more than three thousand years ago. The mushroom grows on a vast number of substrate and environment. Substrate compromises different agro-industrial residues that possess varied property for supporting the growth of mushroom. Though, the most appropriate composition of the substrate should be selected to obtain a better result. Hence, the study was conducted to select appropriate substrate for production of oyster mushroom and to identify the suitable combination from a selected substrate to get a high yield of oyster mushroom. The effects of different selected agro industrial residues on growth and bioconversion efficiency of oyster mushroom was determined. For this study, Oyster mushroom (Pleurotus ostreatus) were grown on different substrates namely cotton seed, enset waste, sawdust, and teff straw with different composition. The spawn was produced using three grains to know the performance of oyster mushroom. The main step used for oyster mushroom production includes preparation of culture media, spawn production, preparation of the substrate, fruiting, and harvesting. The highest bioconversion efficiency and yield were obtained from the combination of sawdust and teff straw. While the lowest yield and bioconversion efficacy was obtained from combination teff straw and enset waste. Key words: Mushroom, oyster, spawn, substrate, waste.

Unique glucose oxidation catalysis of Gluconobacter oxydans constitutes an efficient cellulosic gluconic acid fermentation free of inhibitory compounds disturbance.

Toxic inhibitory compounds from lignocellulose pretreatment are the major obstacle to achieve high bioconversion efficiency in biorefinery fermentations. This study shows a unique glucose oxidation catalysis of Gluconobacter oxydans with its gluconic acid productivity free of inhibitor disturbance. The microbial experimentations and the transcriptome analysis revealed that both the activity of the membrane-bound glucose dehydrogenase and the transcription level of the genes in periplasmic glucose oxidation respiratory chain of G. oxydans were essentially not affected in the presence of inhibitory compounds. G. oxydans also rapidly converted furan and phenolic aldehyde inhibitors into the less toxic alcohols or acids. The synergy of the robust periplasmic glucose oxidation and the rapid inhibitor conversion of G. oxydans significantly elevated the efficiency of the oxidative fermentation in lignocellulose hydrolysate. The corresponding genes responsible for the conversion of furan and phenolic aldehyde inhibitors were also mined by DNA microarrays. The synergistic mechanism of G. oxydans provided an important option of metabolic modification for enhancing inhibitor tolerance of general fermentation strains.

Bioconversion of oat hull and miscanthus cellulose to glucose solutions

Cellulose-containing raw materials are currently considered to be among the most promising types of raw materials for the production of value-added bio-products. However, for the implementation of the developed process, the application of universal pre-processing methods is a prerequisite. In the present paper, a study into the bioconversion of oat hull and miscanthus cellulose samples by enzymatic hydrolysis into glucose solutions is presented. The substrates were obtained by two-stage processing of raw materials with dilute solutions of nitric acid and sodium hydroxide. Enzymatic hydrolysis was carried out using the Cellolux-A and Ultraflo Core enzyme preparations at an initial substrate concentration of 40 g/L. At the first stage, the reactivity of the substrates to enzymatic hydrolysis in an acetate buffer solution was studied over a period of 72 hours. Cellulose samples from both types of raw materials were established to possess equally high reactivity in terms of the reducing substances. Glucose obtained from the substrate yielded 94–95 % and 88–91 %, respectively. This indicates the universality of the pre-treatment method used for raw materials having a cellulose content of 35–45 %. At the second stage, hydrolysis of the substrates was carried out using a pilot fermenter in an aqueous medium with an excess of enzyme preparations. Over a period of 32 hours, aqueous hydrolysates were obtained with a concentration of reducing substances and glucose equal to 42 g/L (94 % yield from the substrate) and 33–35 g/L (74–78 % yield from the substrate), respectively. The glucose (79–83 %) and pentose (1–2 %) content of the reducing substances indicates glucose to predominate in the composition of the resulting solutions. The high bioconversion efficiency rate is additionally demonstrated by a comparative analysis of scanning electron spectroscopy results for substrates and residues following hydrolysis in a pilot fermenter. Glucose solutions obtained in an aqueous medium are emerging as promising materials for the preparation of culture media and the synthesis of valuable metabolites. The authors declare no conflict of interests regarding the publication of this article.

Effects of Different Genotypes of Switchgrass as a Bioenergy Crop on Yield Components and Bioconversion Potential

Switchgrass (Panicum virgatum L.) is a native warm-season grass and it is one of potential bioenergy crops. The objectives of this study were to: 1) assess the best performing switchgrass genotype suitable for Kansas soil and climatic condition in the USA, 2) determine the correlation between plant height or tiller numbers per plant and dry biomass of various switchgrass genotypes, and 3) assess a bioconversion efficiency of certain varieties of switchgrass. Twenty-two different genotypes of seedlings were allowed to grow in cones for 30 days under controlled environments. The genotype Cave-in-Rock was the shortest among the genotypes. Significant difference in number of tillers per plant was observed among the genotypes. The genotypes Alamo recorded the highest numbers of tiller plant-1 and the genotype Cave-in-Rock had the lowest numbers of tiller plant-1 compared with other genotypes. The genotypes Alamo, NL 94 C2-2, NL 94 C2-3, NSL 2009-1 and NSL 2009-2 had increased above ground biomass compared with other genotypes. The correlation study indicates that there was a significant positive correlation between number of tillers per plant and per plant dry weight (R2 = 0.93), number of tillers per plant and plant height (R2 = 0.94), and plant height and per plant dry weight (R2 = 0.82). Based on the biomass composition, the SWG 2007-2 genotype was the promising switchgrass line for the bioconversion through the sugar platform route due to high carbohydrate and low lignin content. On the other hand, the high biomass yield per unit area of field in NL 94 C2-1 led this genotype with the highest total carbohydrate yield per unit area of field despite the lowest total carbohydrate content in the genotype. These results are pertinent for crop breeders to develop the most promising switchgrass line with high biomass yield and high bioconversion efficiency to produce biofuel through the sugar platform route.

Enhanced light-driven catalytic performance of cytochrome P450 confined in macroporous silica.

A light-driven approach combined with a macroporous reactor for the enzymatic biocatalytic reaction has been developed by confining the enzyme/photosensitizer nanohybrids in a macroporous material, which exhibits high bio-conversion efficiency due to the fast diffusion and collision between the enzyme/photosensitizer nanohybrid and the substrate in the reactor.

11 β-Hydroxylation of cortexolone using immobilized Cunninghamella elegans protoplasts

Transformation of cortexolone to cortisol and prednisolone by the filamentous fungus Cunninghamella elegans protoplasts as a research tool was studied. The immobilized protoplasts of the fungus hydroxylated cortexolone at 11β -position had significantly higher activity than the free protoplasts. Sucrose as an osmotic stabilizer was found to be best at 0.6 M level. Relatively higher cortexolone bioconversion was obtained on using 3 ml of protoplasts (1.2iN107 protoplasts/ml) entrapped in 3% calcium alginate gel after 18 h incubation. The addition of some supplements was also investigated. The highest bioconversion efficiency was recorded with sodium citrate (1 g/L) and sodium benzoate (1 g/L). Similarly, the bioconversion process was fairly enhanced in the presence of Tween 20, 60 and the tested vitamins supplements. The entrapped protoplasts proved to be able to maintain the bioconversion process for repeated 13 cycles over 252 h. Sodium citrate and sodium benzoate, folic acid, riboflavin, menadione, vitamin B12 and ascorbic acid relatively were able to increase bioconversion efficiency. Key words : Cortexolone, 11£β-hydroxylation, immobilization, Cunninghamella elegans, protoplasts.

Reproductive performance of four aphidophagous ladybirds on cowpea aphid, Aphis craccivora Koch

Abstract: This study investigated prey consumption, egg production, percent progeny loss, reproductive, pre‐ and post‐reproductive periods, reproductive time ratio, reproductive rate and bioconversion efficiency of four aphidophagous ladybirds, viz. Cheilomenes sexmaculata (Fabricius), Coccinella septempunctata Linnaeus, Coccinella transversalis Fabricius and Propylea dissecta (Mulsant) on Dolichos lablab Linnaeus infested with cowpea aphid, Aphis craccivora Koch. C. sexmaculata had the highest bioconversion efficiency, reproductive rate and reproductive time ratio followed in rank order by P. dissecta, C. transversalis and C. septempunctata. This study indicates that C. sexmaculata has a narrow ecological relationship with A. craccivora. The increased allocation of resources to reproduction as indicated through a high reproductive time ratio and high bioconversion efficiency of C. sexmaculata and P. dissecta suggest that they may be better adapted to compete for this prey with larger species like C. transversalis and C. septempunctata.

High-rate biodegradation of 3- and 4-nitroaniline

A municipal wastewater biosludge was acclimated to the degradation of 4-nitroaniline (4-NA). The acclimation was achieved by using this compound as the sole source of nitrogen during the degradation of succinate as the sole source of carbon and energy. The acclimated bacteria were able to eliminate and mineralize 4-NA as the sole source of carbon and energy. However, in batch tests, the degradation process was somewhat instable and only occurred at comparatively low rates. A continuously operated miniaturized fixed-bed bioreactor was used in order to increase the degradation rates. It was inoculated with the acclimated bacteria and fed with 4-NA as the sole substrate. The system enabled high bioconversion efficiency, due to the development of a high biomass concentration of up to 5.45 g SS L −1. At input concentrations of 4-NA up to 4.5 mM and a hydraulic retention time of 3.5 hours a high degradation rate of 1.1 mmol 4-NA L −1 h −1 and 90–95% DOC removal were achieved. Partial nitrification, also occurre. After gradual adaptation, the bacteria also degraded 3-NA and 4-NA simultaneously in this system. Additional batch tests showed, that 3-NA can serve as the sole source of carbon, nitrogen and energy.