Exploration of upstream and downstream process for microwave assisted sustainable biodiesel production from microalgae Chlorella vulgaris

The present study explores the integrated approach for the sustainable production of biodiesel from Chlorella vulgaris microalgae. The microalgae were cultivated in 10m(2) open raceway pond at semi-continuous mode with optimum volumetric and areal production of 28.105kg/L/y and 71.51t/h/y, respectively. Alum was used as flocculent for harvesting the microalgae and optimized at different pH. Lipid was extracted using chloroform: methanol (2:1) and having 12.39% of FFA. Effect of various reaction conditions such as effect of catalyst, methanol:lipid ratio, reaction temperature and time on biodiesel yields were studied under microwave irradiation; and 84.01% of biodiesel yield was obtained under optimized reaction conditions. A comparison was also made between the biodiesel productions under conventional heating and microwave irradiation. The synthesized biodiesel was characterized by (1)H NMR, (13)C NMR, FTIR and GC; however, fuel properties of biodiesel were also studied using specified test methods as per ASTM and EN standards.

Green coconut mesocarp pretreated by an alkaline process as raw material for bioethanol production

Cocos nucifera L., coconut, is a palm of high importance in the food industry, but a considerable part of the biomass is inedible. In this study, the pretreatment and saccharification parameters NaOH solution, pretreatment duration and enzyme load were evaluated for the production of hydrolysates from green coconut mesocarp using 18% (w/v) total solids (TS). Hydrolysates were not detoxified in order to preserve sugars solubilized during the pretreatment. Reduction of enzyme load from 15 to 7.5 filter paper cellulase unit (FPU)/g of biomass has little effect on the final ethanol titer. With optimized pretreatment and saccharification, hydrolysates with more than 7% (w/v) sugars were produced in 48h. Fermentation of the hydrolysate using industrial Saccharomyces cerevisiae strains produced 3.73% (v/v) ethanol. Our results showed a simple pretreatment condition with a high-solid load of biomass followed by saccharification and fermentation of undetoxified coconut mesocarp hydrolysates to produce ethanol with high titer.

Improved enzymatic saccharification of steam exploded cotton stalk using alkaline extraction and fermentation of cellulosic sugars into ethanol

Cotton stalk, a widely available and cheap agricultural residue lacking economic alternatives, was subjected to steam explosion in the range 170-200°C for 5min. Steam explosion at 200°C and 5min led to significant hemicellulose solubilization (71.90±0.10%). Alkaline extraction of steam exploded cotton stalk (SECOH) using 3% NaOH at room temperature for 6h led to 85.07±1.43% lignin removal with complete hemicellulose solubilization. Besides, this combined pretreatment allowed a high recovery of the cellulosic fraction from the biomass. Enzymatic saccharification was studied between steam exploded cotton stalk (SECS) and SECOH using different cellulase loadings. SECOH gave a maximum of 785.30±8.28mg/g reducing sugars with saccharification efficiency of 82.13±0.72%. Subsequently, fermentation of SECOH hydrolysate containing sugars (68.20±1.16g/L) with Saccharomyces cerevisiae produced 23.17±0.84g/L ethanol with 0.44g/g yield.

Pretreatment of bamboo by ultra-high pressure explosion with a high-pressure homogenizer for enzymatic hydrolysis and ethanol fermentation

Bamboo shoots, 2- and 5-year-old bamboo were treated by using a homogenizer in a constant suspended state, a process termed as ultra-high pressure explosion (UHPE). The bamboo powder was heated in 2% NaOH solution at 121°C, and then 100MPa UHPE-treated through a homogenizer. The results verified that UHPE changed the suspension solution of powder into a stick fluid. The contents of lignin were decreased significantly. The bamboo shoots and 2-year-old bamboo were completely hydrolyzed to glucose within 48h by enzymes loading of 15 FPU of cellulase and 30IU of β-glucosidase per gram glucan. Fermentation of enzymatic hydrolyzates with Saccharomyces cerevisiae resulted in about 89.7-95.1% of the theoretical ethanol yield after 24h. Therefore, NaOH+UHPE is argued to be a potential alternative technology for pretreatment of bamboo.

Efficacy Assessment of Nucleic Acid Decontamination Reagents Used in Molecular Diagnostic Laboratories

The occurrence of nucleic acid cross contamination in the laboratory resulting in false positive results of diagnostic samples is seriously problematic. Despite precautions to minimize or even avoid nucleic acid cross contaminations, it may appear anyway. Until now, no standardized strategy is available to evaluate the efficacy of commercially offered decontamination reagents. Therefore, a protocol for the reliable determination of nucleic acid decontamination efficacy using highly standardized solution and surface tests was established and validated. All tested sodium hypochlorite-based reagents proved to be highly efficient in nucleic acid decontamination even after short reaction times. For DNA Away, a sodium hydroxide-based decontamination product, dose- and time-dependent effectiveness was ascertained. For two other commercial decontamination reagents, the phosphoric acid-based DNA Remover and the non-enzymatic reagent DNA-ExitusPlus^™ IF, no reduction of amplifiable DNA/RNA was observed. In conclusion, a simple test procedure for evaluation of the elimination efficacy of decontamination reagents against amplifiable nucleic acid is presented.

[Efficacy of sodium hydroxide at 2.5 %, chlorhexidine gluconate at 0.5 % and calcium hydroxide against Candida albicans]

INTRODUCTION

Endodontic flora is dominated in the apical part of the channels by strict anaerobic and some facultative anaerobic bacteria but also by Candida yeasts, especially Candida albicans species that are involved in the maintenance and persistence of endodontic infections. Their elimination of the canal system in practice by chemo-mechanical methods of disinfection is not always guaranteed. Thus, this in vitro study was performed to determine the sensitivity of C. albicans with sodium hypochlorite (NaOCl) dosed at 2.5 %, the chlorhexidine digluconate 0.5 % and calcium hydroxide used in inter-session medication.

METHODS

The diffusion method was used initially to test the sensitivity of C. albicans strains with the above products. Then a dilution technique has allowed us to determine the minimum inhibitory concentration of these active products on C. albicans.

RESULTS

Strains from infected pulp teeth of patients showed a sensitivity of C. albicans to sodium hypochlorite to a minimum inhibitory concentration less than 70μg/mL and 30μg/mL for chlorhexidine.

CONCLUSION

This study demonstrated a sensitivity of C. albicans to sodium hypochlorite and chlorhexidine.

Comparison of alkali treatments for efficient release of p-coumaric acid and enzymatic saccharification of sorghum pith

Two separate temperature and time ranges were respectively conducted for optimizing release of p-coumaric acid and enzymatic saccharification of sorghum pith by NaOH pretreatment using response surface methodology. Two desirable pretreatment conditions were selected as follows: 37°C, 2% NaOH and 12h, and 100°C, 1.75% NaOH and 37min in the low and high temperature ranges, respectively. Under these conditions, the enzymatic glucose yields were 85.6% and 90.4% respectively, whereas p-coumaric acid yields were 95.1% and 98.1% respectively. The final recovery of esterified p-coumaric acid reached 82.8% and 87.4% respectively after further separation with HP-20 resin. Interestingly, strong linear correlations exist between p-coumaric acid release with glucan saccharification yield and lignin dissolution. These results indicate that sorghum pith could be an attractive source for natural p-coumaric acid and efficient release of p-coumaric acid and enzymatic saccharification of sorghum pith can be achieved by mild NaOH pretreatment.

Effect of thermal, acid, alkaline and alkaline-peroxide pretreatments on the biochemical methane potential and kinetics of the anaerobic digestion of wheat straw and sugarcane bagasse

The effect of thermal, acid, alkaline and alkaline-peroxide pretreatments on the methane produced by the anaerobic digestion of wheat straw (WS) and sugarcane bagasse (SCB) was studied, using whole slurry and solid fraction. All the pretreatments released formic and acetic acids and phenolic compounds, while 5-hydroxymetilfurfural (HMF) and furfural were generated only by acid pretreatment. A remarkable inhibition was found in most of the whole slurry experiments, except in thermal pretreatment which improved methane production compared to the raw materials (29% for WS and 11% for SCB). The alkaline pretreatment increased biodegradability (around 30%) and methane production rate of the solid fraction of both pretreated substrates. Methane production results were fitted using first order or modified Gompertz equations, or a novel model combining both equations. The model parameters provided information about substrate availability, controlling step and inhibitory effect of compounds generated by each pretreatment.

Improving enzymatic saccharification of bamboo shoot shell by alkalic salt pretreatment with H2O2

Pretreatment of bamboo shoot shell (BSS) by a combination of alkalic salts with hydrogen peroxide (H2O2) was evaluated for its delignification effect and for its ability to enhance enzymatic saccharification of pretreated solids. By comparing different alkalic salts, the combination of 9% Na3PO4·12H2O and 0.3g/g H2O2 (ASHP) was identified as an effective system that showed the highest delignification of 87.7% and the total reducing sugar yield of 97.1% when pretreated BSS at a solid to liquid ratio of 1/20 (w/w) at 80°C for 2h. The delignification effect and the disruption of the lignocelluloses structure by this novel pretreatment method were deduced to be the main reasons that led to enhanced enzymatic saccharification as supported by the chemical composition analysis and the results of SEM, FTIR and XRD analyses of the untreated and alkalic salt pretreated BSS.

Inhibition of alkaline flocculation by algal organic matter for Chlorella vulgaris

Alkaline flocculation is a promising strategy for the concentration of microalgae for bulk biomass production. However, previous studies have shown that biological changes during the cultivation negatively affect flocculation efficiency. The influence of changes in cell properties and in the quality and composition of algal organic matter (AOM) were studied using Chlorella vulgaris as a model species. In batch cultivation, flocculation was increasingly inhibited over time and mainly influenced by changes in medium composition, rather than biological changes at the cell surface. Total carbohydrate content of the organic matter fraction sized bigger than 3 kDa increased over time and this fraction was shown to be mainly responsible for the inhibition of alkaline flocculation. The monosaccharide identification of this fraction mainly showed the presence of neutral and anionic monosaccharides. The addition of 30-50 mg L(-1) alginic acid, as a model for anionic carbohydrate polymers containing uronic acids, resulted in a complete inhibition of flocculation. These results suggest that inhibition of alkaline flocculation was caused by interaction of anionic polysaccharides leading to an increased flocculant demand over time.

Optimization of hydrolysis and volatile fatty acids production from sugarcane filter cake: Effects of urea supplementation and sodium hydroxide pretreatment

Different methods for optimization the anaerobic digestion (AD) of sugarcane filter cake (FC) with a special focus on volatile fatty acids (VFA) production were studied. Sodium hydroxide (NaOH) pretreatment at different concentrations was investigated in batch experiments and the cumulative methane yields fitted to a dual-pool two-step model to provide an initial assessment on AD. The effects of nitrogen supplementation in form of urea and NaOH pretreatment for improved VFA production were evaluated in a semi-continuously operated reactor as well. The results indicated that higher NaOH concentrations during pretreatment accelerated the AD process and increased methane production in batch experiments. Nitrogen supplementation resulted in a VFA loss due to methane formation by buffering the pH value at nearly neutral conditions (∼ 6.7). However, the alkaline pretreatment with 6g NaOH/100g FCFM improved both the COD solubilization and the VFA yield by 37%, mainly consisted by n-butyric and acetic acids.

Biobutanol production from corn stover hydrolysate pretreated with recycled ionic liquid by Clostridium saccharobutylicum DSM 13864

In this study, corn stover (CS) hydrolysates, pretreated by fresh and recycled ionic liquid (IL) [Bmim][Cl], were utilized in butanol fermentation by Clostridium saccharobutylicum DSM 13864. An efficient CS pretreatment procedure using [Bmim][Cl] was developed, giving a glucose concentration of 18.7 g L(-1) using ten times recycled [Bmim][Cl], representing about 77% of that produced with fresh IL (24.2 g L(-1)). Fermentation of hydrolysate I (pretreated by fresh IL) resulted in 7.4 g L(-1) butanol with a yield of 0.21 g g total-sugar(-1) and a productivity of 0.11 g L(-1)h(-1), while 7.9 g L(-1) butanol was achieved in fermentation using hydrolysate II (pretreated by ten times reused IL) with similar levels of acetone and ethanol, as well as yield and productivity. This study provides evidence for the efficient utilization of IL in CS pretreatment for biobutanol fermentation.

Development of a novel sequential pretreatment strategy for the production of bioethanol from sugarcane trash

A novel sequential pretreatment strategy using biodiesel industry generated waste glycerol assisted transition metal and alkali pretreatment of sugarcane trash were developed for the production of bioethanol. Various process parameters affecting pretreatment as well as hydrolysis were optimized by adopting a Taguchi design. This novel method was found to be superior when compared to conventional pretreatment strategies like acid and alkali in removing hemicelluloses and lignin and the hydrolyzate is devoid of major fermentation inhibitors like organic acids and furfurals. Physico-chemical changes of the native and the pretreated biomass were evaluated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analysis. Under optimized hydrolysis conditions 0.796 g of reducing sugar (pentoses and hexoses) per g of dry biomass after saccharification was produced. Fermentation of the non-detoxified hydrolyzate using Saccharomyces cerevisiae produced 31.928 g of bioethanol per g of dry biomass with an efficiency of 78.89%.

Enhanced biohydrogen production from sugarcane bagasse by Clostridium thermocellum supplemented with CaCO3

Clostridium thermocellum ATCC 27405 was used to degrade sugarcane bagasse (SCB) directly for hydrogen production, which was significantly enhanced by supplementing medium with CaCO3. The effect of CaCO3 concentration on the hydrogen production was investigated. The hydrogen production was significantly enhanced with the CaCO3 concentration increased from 10mM to 20mM. However, with the CaCO3 concentration further increased from 20mM to 100mM, the hydrogen production didn't increase further. Under the optimal CaCO3 concentration of 20mM, the hydrogen production reached 97.83±5.19mmol/L from 2% sodium hydroxide-pretreated SCB, a 116.72% increase over the control (45.14±1.03mmol/L), and the yield of hydrogen production reached 4.89mmol H2/g SCBadded. Additionally, CaCO3 promoted the biodegradation of SCB and the growth of C. thermocellum. The stimulatory effects of CaCO3 on biohydrogen production are mainly attributed to the buffering capacity of carbonate. The study provides a novel strategy to enhance biohydrogen production from lignocellulose.

Evaluation of several flocculants for flocculating microalgae

Flocculation of microalgae with chitosan, polyacrylamide, Al2(SO4)3, NaOH and HNO3 was evaluated. Their flocculation efficiencies and optimal dosages were discussed. The effects of the flocculants on cells viability were also investigated and the cells were found to be intact during the flocculation process. Moreover, the effects of flocculants on the extractions were evaluated. Lipid content after flocculants treatments showed no significant differences. Carbohydrate content was lower but protein content was higher after NaOH treatment than those after other treatments. Furthermore, the five flocculated media maintained approximate growth yields to that of the fresh medium in microalgal cultivation, indicating the five flocculated media could be recycled, thereby reducing the cost of biodiesel production from microalgae. Finally, economic comparison of the flocculants was made and the cost of using HNO3, including flocculating cells and recycling medium, was found to be the lowest.

Evaluation of the microbial cell structure damages in alkaline pretreatment of waste activated sludge

This study investigated the damages of microbial cell structures, as well as the relationships between these damages and the release of cellular organic matter in the pretreatment of waste activated sludge (WAS) by using alkaline pretreatment as model. In the alkaline pretreatment of WAS, the most damage of bound extracellular polymeric substances (EPS), cell walls, cell membranes, and cell nuclei occurred at pH 11.5-12.0 (46.2%), pH 11.0-11.5 (27.3%), pH 9.0-10.0 (34.2%), and pH 11.5-12.0 (44.4%), respectively. The damage percentages of these cell structures in the pH stabilization stage were low because most of the damages occurred when the pH increased. The structural integrities of sludge microorganisms were all damaged in the pH increase stage. The damages of EPS, cell walls, and cell membranes were significantly correlated with the release of cellular organic matter, and these damages were necessary to release the cellular matter in WAS.

Effects of thermo-chemical pretreatment plus microbial fermentation and enzymatic hydrolysis on saccharification and lignocellulose degradation of corn straw

In order to increase corn straw degradation, the straw was kept in the combined solution of 15% (w/w) lime supernatant and 2% (w/w) sodium hydroxide with liquid-to-solid ratio of 13:1 (mL/g) at 83.92°C for 6h; and then added with 3% (v/v) H2O2 for reaction at 50°C for 2h; finally cellulase (32.3 FPU/g dry matter) and xylanase (550 U/g dry matter) was added to keep at 50°C for 48 h. The maximal reducing sugars yield (348.77 mg/g) was increased by 126.42% (P<0.05), and the degradation rates of cellulose, hemicellulose and lignin in pretreated corn straw with enzymatic hydrolysis were increased by 40.08%, 45.71% and 52.01%, compared with the native corn straw with enzymatic hydrolysis (P<0.05). The following study indicated that the combined microbial fermentation and enzymatic hydrolysis could further increase straw degradation and reducing sugar yield (442.85 mg/g, P<0.05).

Lignin preparation from oil palm empty fruit bunches by sequential acid/alkaline treatment--A biorefinery approach

Lignin is an important raw material for the sustainable biorefineries and also the forerunner of high-value added products, such as biocomposite for chemical, pharmaceutical and cement industries. Oil palm empty fruit bunches (OPEFB) were used for lignin preparation by successive treatment with 1% (w/w) H2SO4 at 121°C for 60 min and 2.5% NaOH at 121°C for 80 min resulting in the high lignin yield of 28.89%, corresponding to 68.82% of the original lignin. The lignin obtained was characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The results indicated a lignin with molecular masses ramping from 4500 kDa to 12,580 kDa. FTIR and NMR of these lignins showed more syringyl and p-hydroxyphenyl than guaiacyl units. Moderate acid/alkaline treatment provided lignin with high industrial potential and acid hydrolyzates rich in fermentable sugars and highly porous cellulosic fibers.

Enhancement of enzymatic saccharification of corn stover with sequential Fenton pretreatment and dilute NaOH extraction

In this study, an effective method by the sequential Fenton pretreatment and dilute NaOH extraction (FT-AE) was chosen for pretreating corn stover. Before dilute NaOH (0.75 wt%) extraction at 90 °C for 1h, Fenton reagent (0.95 g/L of FeSO4 and 29.8 g/L of H2O2) was employed to pretreat CS at a solid/liquid ratio of 1/20 (w/w) at 35 °C for 30 min. The changes in the cellulose structural characteristics (porosity, morphology, and crystallinity) of the pretreated solid residue were correlated with the enhancement of enzymatic saccharification. After being enzymatically hydrolyzed for 72 h, the reducing sugars and glucose from the hydrolysis of 60 g/L FT-AE-CS pretreated could be obtained at 40.96 and 23.61 g/L, respectively. Finally, the recovered hydrolyzates containing glucose had no inhibitory effects on the ethanol fermenting microorganism. In conclusion, the sequential Fenton pretreatment and dilute NaOH extraction has high potential application in future.

Mycelial Mattress from a Sporangia Formation-Delayed Mutant of Rhizopus stolonifer as Wound Healing-Enhancing Biomaterial

A mycelial mattress of Rhizopus stolonifer obtained from a liquid static culture was utilized for wound dressing and biomedical use. Following screening of mutants induced by UV radiation, F6, exhibiting delayed sporangium formation was selected because its sporangium maturation exhibited a 5-day delay without significant loss of mycelial weight compared to the wild type. The sporangium-free mycelial mattress from the sporangiospore culture of F6 was treated with 1N sodium hydroxide NaOH at 85°C for 2 h to produce a sponge-like membrane named Rhizochitin. The trifluoroacetic acid hydrolysate of Rhizochitin contained 36% N-acetylglucosamine and 53% hexose respectively detected by the Elson-Morgen and phenol-sulfuric acid methods. Results indicated the wound area in rats covered with Rhizochitin was 40% less than that of the uncovered group. Rhizochitin decreased the expression of PDGF in the proliferation stage, increased the expression of TGF-β in the inflammation and proliferation stages, and increased the expression of VEGF in the inflammation and proliferation stages. Rhizochitin inhibited secretion of matrix metalloproteinase-9 on days 1, 7, 9, and 12 and matrix metalloproteinase-2 on days 3, 7, 9, and 12. It was concluded that Rhizochitin has beneficial properties of biocompatible, biodegradable, and wound healing.

Effect of a new regeneration process by adsorption-coagulation and flocculation on the physicochemical properties and the detergent efficiency of regenerated cleaning solutions

Reprocessing soiled cleaning-in-place (CIP) solutions has large economic and environmental costs, and it would be cheaper and greener to recycle them. In food industries, recycling of CIP solutions requires a suitable green process engineered to take into account the extreme physicochemical conditions of cleaning while not altering the process efficiency. To this end, an innovative treatment process combining adsorption-coagulation with flocculation was tested on multiple recycling of acid and basic cleaning solutions. In-depth analysis of time-course evolutions was carried out in the physicochemical properties (concentration, surface tension, viscosity, COD, total nitrogen) of these solutions over the course of successive regenerations. Cleaning and disinfection efficiencies were assessed based on both microbiological analyses and organic matter detachment and solubilization from fouled stainless steel surfaces. Microbiological analyses using a resistant bacterial strain (Bacillus subtilis spores) highlighted that solutions regenerated up to 20 times maintained the same bactericidal efficiency as de novo NaOH solutions. The cleanability of stainless steel surfaces showed that regenerated solutions allow better surface wettability, which goes to explain the improved detachment and solubilization found on different types of organic and inorganic fouling.

Lignin extraction distinctively enhances biomass enzymatic saccharification in hemicelluloses-rich Miscanthus species under various alkali and acid pretreatments

In this study, one- and two-step pretreatments with alkali and acid were performed in the three Miscanthus species that exhibit distinct hemicelluloses levels. As a result, one-step with 4% NaOH or two-step with 2% NaOH and 1% H2SO4 was examined to be optimal for high biomass saccharification, indicating that alkali was the main effecter of pretreatments. Notably, both one- and two-step pretreatments largely enhanced biomass digestibility distinctive in hemicelluloses-rich samples by effectively co-extracting hemicelluloses and lignin. However, correlation analysis further indicated that the effective lignin extraction, other than the hemicelluloses removals, predominately determined biomass saccharification under various alkali and acid pretreatments, leading to a significant alteration of cellulose crystallinity. Hence, this study has suggested the potential approaches in bioenergy crop breeding and biomass process technology.

Significantly improving enzymatic saccharification of high crystallinity index's corn stover by combining ionic liquid [Bmim]Cl-HCl-water media with dilute NaOH pretreatment

In this study, a pretreatment by combining acidified aqueous ionic liquid 1-butyl-3-methylimidazolium chloride (IL [Bmim]Cl) solution with dilute NaOH extraction was employed to pretreat high crystallinity index (CrI) of corn stover before its enzymatic saccharification. After NaOH extraction, [Bmim]Cl-HCl-water (78.8:1.2:20, w/w/w) media was used for further pretreatment at 130 °C for 30 min. After being enzymatically hydrolyzed for 48 h, corn stover pretreated could be biotransformed into reducing sugars in the yield of 95.1%. Furthermore, SEM, XRD and FTIR analyses of untreated and pretreated corn stovers were examined. It was found that the intact structure was disrupted by combination pretreatment and resulted in a porous and amorphous regenerated cellulosic material that greatly improved enzymatic hydrolysis. Finally, the recovered hydrolyzates obtained from the enzymatic hydrolysis of pretreated corn stovers could be fermented into ethanol efficiently. In conclusion, the combination pretreatment shows high potential application in future.

Steam explosion distinctively enhances biomass enzymatic saccharification of cotton stalks by largely reducing cellulose polymerization degree in G. barbadense and G. hirsutum

In this study, steam explosion pretreatment was performed in cotton stalks, leading to 5-6 folds enhancements on biomass enzymatic saccharification distinctive in Gossypium barbadense and Gossypium hirsutum species. Sequential 1% H2SO4 pretreatment could further increase biomass digestibility of the steam-exploded stalks, and also cause the highest sugar-ethanol conversion rates probably by releasing less inhibitor to yeast fermentation. By comparison, extremely high concentration alkali (16% NaOH) pretreatment with raw stalks resulted in the highest hexoses yields, but it had the lowest sugar-ethanol conversion rates. Characterization of wall polymer features indicated that biomass saccharification was enhanced with steam explosion by largely reducing cellulose DP and extracting hemicelluloses. It also showed that cellulose crystallinity and arabinose substitution degree of xylans were the major factors on biomass digestibility in cotton stalks. Hence, this study has provided the insights into cell wall modification and biomass process technology in cotton stalks and beyond.