Identifying Advanced Biotechnologies to Generate Biofertilizers and Biofuels From the World’s Worst Aquatic Weed

Water hyacinth (Eichhornia crassipes L.) was introduced as an invasive plant in freshwater bodies more particularly in Asia and Africa. This invasive plant grows rapidly and then occupies a huge layer of freshwater bodies. Hence, challenges are facing many countries for implementing suitable approaches for the valorization of the world’s worst aquatic weed, and water hyacinth (WH). A critical and up-to-date review article has been conducted for more than 1 year, based on more than 100 scientific journal articles, case studies, and other scientific reports. Worldwide distribution of WH and the associated social, economic, and environmental impacts were described. In addition, an extensive evaluation of the most widely used and innovative valorization biotechnologies, leading to the production of biofertilizer and bioenergy from WH, and was dressed. Furthermore, an integrated search was used in order to examine the related advantages and drawbacks of each bioprocess, and future perspectives stated. Aerobic and anaerobic processes have their specific basic parameters, ensuring their standard performances. Composting was mostly used even at a large scale, for producing biofertilizers from WH. Nevertheless, this review explored some critical points to better optimize the conditions (presence of pollutants, inoculation, and duration) of composting. WH has a high potential for biofuel production, especially by implementing several pretreatment approaches. This review highlighted the combined pretreatment (physical-chemical-biological) as a promising approach to increase biofuel production. WH valorization must be in large quantities to tackle its fast proliferation and to ensure the generation of bio-based products with significant revenue. So, a road map for future researches and applications based on an advanced statistical study was conducted. Several recommendations were explored in terms of the choice of co-substrates, initial basic parameters, and pretreatment conditions and all crucial conditions for the production of biofuels from WH. These recommendations will be of a great interest to generate biofertilizers and bioenergy from WH, especially within the framework of a circular economy.

Development of parameters for the production of biomass and biohydrogen from brewer’s grain

In this work, suitable pretreatment conditions have been studied to increase hydrogen production by dark fermentation of brewer’s grain (BG). All samples with different concentrations of raw materials were tested: treatment with sulfuric acid with a concentration of 1.5%, autoclaving at 121 ◦C, purification from impurities by filtration, centrifugation and calibration of the pH of the medium to 7.5 units. The choice of acid hydrolysis is due to the fact that this type of pretreatment is the most suitable for the further commercialization of this technology. Also, pretreatment performs the task of suppressing methanogens and creating conditions for the life of hydrogen-producing bacteria. Experiments were carried out under mesophilic conditions ( 37 ◦C) using wild-type and multiple mutant E. coli. The highest sugar yields were obtained at a 4% concentration of brewer’s grains and in the presence of a concentration of 1.5% sulfuric acid in the original substrate. The results of the experiments showed that brewer’s grains are a valuable product as a source of carbon and energy for microorganisms in the production of biohydrogen, as well as for the production of biomass for further production of value-added products.

Effect of Pressure on Alkaline Pretreated Sugar Cane Bagasse for Enhanced Bioethanol Production

Global warming has become a major concern as a result of the excessive release of greenhouse gas emissions. An important strategy for achieving carbon neutrality targets is to focus on renewable energy resources. Second generation bioethanol synthesis via sugarcane bagasse (SCB) is another promising approach for the reduction of greenhouse gas emissions. Here in, this study presents the second generation of bioethanol production from sugarcane bagasse with the pretreatment condition adjoined with basic hydrogen peroxide and pressure effect by fermentation using microorganisms Saccharomyces Cerevisiae and Bacillus Subtilis. The results revealed better production through pretreatment at different operational stages through batch fermentation. Different characterization techniques including Scanning Electron Microscopy (SEM), Fourier Transform Infra-Red (FTIR), High Performance Liquid Chromatography (HPLC), and Thermogravimetric Analysis (TGA) results confirmed the better effects of structural changes of hemicellulose, lignin, and cellulose during treatment, weight loss, thermal stability, and higher concentration of the produced bioethanol in the distillate After pretreatment, the conversion of biomass to bioethanol by using Saccharomyces Cerevisiae gives a high production yield (70%), which presents a production of 70g/L from 100g of SCB at the end of 72 h and a yield of bioethanol (0.7g/g) of SCB confirmed through gas chromatography/mass spectrometry qualitative analysis (GC/MS). The pretreatment conditions of alkaline hydrogen peroxide (H2O2) were optimized to the values 3h, 50°C, 60 psi, pH 8.6, and 150 rpm. This study sheds light on the effects of pretreatment conditions for bioethanol production from sugarcane bagasse.

Enhanced Leaching of Zinc from Zinc-Containing Metallurgical Residues via Microwave Calcium Activation Pretreatment

Given the shortage of zinc resource, the low utilisation efficiency of secondary zinc resource, and the crucial problem that the synchronous dissolution of zinc from different mineral phases, an activation pretreatment method merged with calcium activation and microwave heating approach was proposed to enhance the zinc leaching from complex encapsulated zinc-containing metallurgical residues (ZMR). Results indicated that under the optimal pretreatment conditions, including microwave activation temperature of 400 °C, CaO addition of 25% and activation time of 20 min, the zinc leaching rate reached 91.67%, which was 3.9% higher than that by conventional roasting pretreatment. Meanwhile, microwave heating presents excellent treatment effects, manifested by the zinc leaching rates, all exceeding that of conventional roasting under the same conditions, while the process temperature is decreased by 200 °C. In addition, XRD and SEM-EDS analysis denoted that microwave calcification pretreatment can effectively promote the transformation of the refractory zinc minerals like Zn2SiO4 and ZnFe2O4 into the easily leachable zinc oxides. The distinctive selective heating characteristics of microwave heating strengthened the dissociation of mineral inclusion, and the generated cracks increased the interfacial reaction area and further enhancing the leaching reaction of zinc from ZMR.

Box-Behnken design for the optimization of bioethanol production from rice straw and sugarcane bagasse by newly isolated Pichia occidentalis strain AS.2

This study investigated bioethanol production from rice straw (RS) and sugarcane bagasse (SCB) which containing 72.8 and 73.2% holocellulose, 56.8 and 58.6% α-cellulose, and 14.9 and 25.1% lignin for RS and SCB, respectively. To eliminate the lignin content, different pretreatment conditions, such as hot water, dilute acid, and acid-alkali, were designed. Acid-alkali was characterized as the best pretreatment for removing ∼79 and 70% of lignin, α-cellulose increased 91.4 and 91%, and holocellulose reached 90.8 and 90% for RS and SCB, respectively. The results revealed that acid-alkali was highly efficient than other pretreatment used for both RS and SCB. After enzymatic hydrolysis of acid-alkali-treated RS and SCB with cellulase, glucose concentrations reached 45 and 42 g/l, respectively. Pichia occidentalis AS.2 was isolated and identified based on 18S rRNA sequencing as a bioethanol producer. Maximization of bioethanol production by P. occidentalis AS.2 using the resulting glucose as a carbon source from RS and SCB was studied using an experimental design. The pH, incubation period, and inoculum size were optimized using Box-Behnken designs (BBD), the final conditions for bioethanol production used 100 g/l acid-alkali-treated fibers, 10 ml cellulase enzyme at 50°C for 5 days at 75 rpm for enzymatic hydrolysis. After time consumed and adjusting the pH to 6, the mixture was inoculated with 2.5% P. occidentalis AS.2 and incubated at 35°C for 24 h at 200 rpm to increase the bioethanol yield by 1.39-fold to 23.7 and 21.4 g/l compared to initial production (17 and 15.3 g/l) between RS and SCB, respectively.

Simultaneous Determination of Purines and Uric Acid in Chinese Chicken Broth Using TFA/FA Hydrolysis Coupled with HPLC-VWD

Chinese chicken broth is well known for its outstanding nutritional value and flavor, widely consumed in China. This study was designed to develop a sensitive and accurate high-performance liquid chromatography-variable wavelength detector (HPLC-VWD) method to simultaneously determine purines and uric acid in Chinese chicken broth for gout and hyperuricemia dietary management. Chromatographic separation was performed on an Agilent TC-C18 (2) column (4.6 mm × 250 mm, 5.0 µm), using 0.02 M KH2PO4 (pH 4.0) as a mobile phase. Sample pretreatment was optimized to enable the extraction of all analytes from Chinese chicken broth. The optimal pretreatment conditions were chicken broth-60% trifluoroacetic acid (TFA)/20% formic acid (FA) (1:1, v/v) in a volume ratio of 1:3 and hydrolysis for 40 min at 85 °C in a water bath. The limits of detection (LODs) and limits of quantification (LOQs) of the purines and uric acid were 0.58–1.71 µg/L and 1.92–5.70 µg/L, respectively. The recoveries were 91–101%, with the relative standard deviations (RSDs) lower than 3%. The complete method has been successfully applied to determine purines and uric acid in various Chinese chicken soups obtained from different provinces in China.

Rendering Bio-Inert Low Density Polyethylene Amenable For Biodegradation Via Fast High Throughput Reactive Extrusion Assisted Oxidation

An energy efficient high throughput pre-treatment of low density polyethylene (LDPE) using a fast reactive extrusion (REX) assisted oxidation technique followed by bacterial attachment as an indicator for bio-amenability was studied. Silicon dioxide (SiO2) was selected as a model oxidizing and catalytic reagent with the REX process demonstrated to be effective both in the presence and absence of the catalyst. Optimized 5-minute duration pretreatment conditions were determined using Box-Behnken design (BBD) with respect to screws speed, operating temperature, and concentration of SiO2. The crystallinity index, carbonyl index and weight loss (%) of LDPE were used as the studied responses for BDD. FTIR and DSC spectra of the residual LDPE obtained after pretreatment with the REX assisted oxidation technique showed a significant increase in residual LDPE carbonyl index from 0 to 1.04 and a decrease of LDPE crystallinity index from 29% to 18%. Up to 5-fold molecular weight reductions were also demonstrated using GPC. Optimum LDPE pretreatment with a duration of 5 minutes was obtained at low screw speed (50 rpm), operating temperature of 380-390⁰C and variable concentration of SiO2 (0 and 2% (w/w)) indicating that effective pretreatment can occur under noncatalytic and catalysed conditions. Biofilms were successfully formed on pretreated LDPE samples after 14 days of incubation.Furthermore, the technique proposed in this study is expected to provide a high throughput approach for pretreatment of pervasive recalcitrant PE based plastics to reduce their bio inertness.