Low-cost Agro-industrial Waste Research Articles

Investigation of optimal parameters for aspartic protease production from Aspergillus terreus using solid-state fermentation

The current study presents extracellular Aspartic protease production using low-cost agro-industrial waste with the indigenously isolated novel strain Aspergillus terreus, and parameters that largely affect enzyme production, namely fermentation time, pH, moistening solution, temperature, inoculum volume, and different solutions, were utilized for enzyme extraction. The isolated fungus was identified as A. terreus (registered as A. terreus SFH5 in the gene bank) by phenotypic and molecular characterization, showed the highest aspartic protease activity of 258.6 units/mL and 272.2 units/mg using a solid-state fermentation technique during screening, and was further used for media component screening and optimization studies. The study employed wheat bran as the preferred production medium and casein as the nitrogen source. The fermentation process was conducted at a temperature of 30°C and a pH of 5. The moistening solution to fermentation medium ratio was set at 3:1, while an inoculum volume of 2 mL (containing 1 × 106 spores/10 g solid) was used. Distilled water was selected as the most effective solution for extracting the enzyme. It has been discovered that the locally isolated novel strain of A. terreus, SFH5, can efficiently produce a substantial amount of aspartic protease by utilizing agro-industrial waste. This makes it a viable candidate for large-scale optimized production of the enzyme to satisfy industrial requirements.

Scale-up studies for production of α-amylase by A. Tamarii MTCC5152 and development of enzyme product

α-amylases are one of the most vital commercially produced starch hydrolyzing enzymes. Increasing enzyme production is becoming one of the most important goals in biotechnological processes. In this study, the production of α-amylase by A.tamarii MTCC5152 in flask level studies is experimentally validated by scale-up studies in Koji room under controlled conditions using wheat bran, a low cost agro-industrial waste as substrate. The production of amylase was increased by optimising various culture conditions such as inoculum size, incubation period and moisture content. It was found that A.tamarii MTCC5152 produced highest titre of α-amylase activity (668.01 u/g), after 4 days of incubation period at 5% inoculum concentration and 80% moisture content. The results of the comparative analysis of protease and amylase production demonstrated 15% increase in α- amylase and 20% increase in protease production compared to flask level studies. Studies conducted for the development of enzyme products as liquid enzyme concentrate and dry enzyme powder showed that addition of hydrophilic agents such as poly ethylene glycol (PEG- 6000) was found to be an effective way to increase the activity and enzyme yield in the preparation of a dry enzyme powder using A.tamarii MTCC5152. The ammonium sulfate precipitated enzyme at saturation, lyophilized by freeze drying gave the best recovery (96%) of the enzyme activity.

Optimization and production of highly stable amylase isolated from Citrobacter portucalensis using low-cost agro-industrial wastes as substrates: Prospective therapeutics

Starch hydrolyzing amylases are among the vital enzymes used in the food, textile, detergent, and pharmaceutical industries. The aim was to isolate amylase bacteria from agricultural soil, its extraction and subsequent purification. Within the scope of this work, using a 1% starch agar medium, potent thermostable bacterial amylase (A-4) was isolated from agricultural soil samples. Molecular analysis revealed the amylase-producing bacterial strain (A-4) to be Citrobacter portucalensis. We used agro-industrial-based wastes (wheat bran, potato peel, and sugarcane bagasse) in amylase production. Culture condition optimization showed that high amylase activity of 4.96 U/mL was obtained at temperature 55 °C and pH 5.0 after 72 h of incubation. The best-suited substrate was nitrogen, and carbon sources were wheat bran, yeast, and lactose for enzyme production. In addition, metal ions Ca+2 and Mg+2 showed a net positive effect on the rate of the enzymatic reaction, and Al+3 and Co+2 inhibited the activity. Protein purification results demonstrated a 4-fold increase with 13% yield and specific activity of 40 U/mL/min. SDS-PAGE indicated the molecular weight of partially purified protein as ∼56 kDa. The stain removal efficiency of the purified enzyme showed considerable results. The finding revealed the use of low-cost and readily available substrates, making C. portucalensis (A-4) a promising candidate for detergent and pharmaceutical industries.

Microbial synthesis of eco-friendly polylactate plastic from low-cost agro-industrial wastes as an alternative to petrochemical-based plastic

<p>Bioplastics made from renewable resources, such as contemporary biomass, have been developed more quickly as a result of global pollution from plastics made from petroleum, but it is still unclear how these materials will affect ecosystems. A common biopolymer that will make up 33% of the bioplastics produced in 2021 is polylactic acid (PLA). Forty-two bacterial isolates (soil, food wastes, and water wastes) were obtained, and 8 lactic acid bacteria were used for lactic acid (LA) production. These bacteria were classified into three categories, namely high, moderate and low LA producing bacteria which gave LA concentrations ranged from >1.0 g/L (3 bacteria), 0.5 to 1.0 g/L (21 bacteria) and 0.1 to 0.5 g/L (26 bacteria), respectively. The Sudan black staining method revealed that 16 bacteria out of 50 were capable of storing PLA granules, with three lactic acid bacteria referred to as Lactococcus thermophilus, Lactobacillus rhamenose, and Lactobacillus retrieria being the most efficient. The sodium dodecyl sulphate procedure was used to extract PLA from the selected LAB, and the results revealed that L. rhamnose was the most effective strain for producing both lactic acid and PLA. The most important fermentation parameters for lactic acid and polylactate polymer production were evaluated using an optimal custom (factorial) design. The interaction between three factors of selected potato oil waste, C/N ratio (48/1), and inoculum size (10%) resulted in an increase in lactic acid and polylactate polymer productivity by L. rhamenose L6, which reached 0.85 g/L, 0.96 g/L, and cell dry weight 2.33g/L, respectively.</p>

Removal of Metals and Dyes in Water Using Low-Cost Agro-Industrial Waste Materials

The pollution of water bodies due to the discharge of effluents without treatment is a global problem. Therefore, different technologies have been implemented for the removal of contaminants from wastewater before the final disposition. Among them, adsorption processes using residual biomasses are becoming very popular due to the low cost and high availability of adsorbents. Thus, in the present work, the synthesis of modified biochar from agro-industrial residues derived from the wheat-processing industry, as a valorization alternative of these residues, for its use in the removal of Cr (VI) and methylene blue (MB) has been analyzed. The biochar was prepared using a ramp function of 5 °C/min until 250 °C for 30 min. The adsorption tests were developed in a batch system, using 30 mg of adsorbent in 10 mL of solution. From SEM analysis, the formation of tubular cavities and porous structure was seen, caused by the basic hydrolysis with KOH. From adsorption tests, an adsorption capacity of 12.98 mg/g and 97.38% of efficiency for MB at pH 10 was noted, while for Cr (VI), it was 11.35 mg/g and 85.15% at pH 2. Freundlich’s model adjusted the adsorption equilibrium data with R2 > 0.9. The maximum adsorption capacities in the monolayer were 186,375 mg/g and 90.723 mg/g for Cr (VI) and MB, according to Langmuir’s model. From a kinetic study, it can be said that the process occurs by chemisorption through electrostatic interaction and ionic interchange between adsorbate and adsorbent.

System metabolic engineering of Escherichia coli W for the production of 2-ketoisovalerate using unconventional feedstock.

Replacing traditional substrates in industrial bioprocesses to advance the sustainable production of chemicals is an urgent need in the context of the circular economy. However, since the limited degradability of non-conventional carbon sources often returns lower yields, effective exploitation of such substrates requires a multi-layer optimization which includes not only the provision of a suitable feedstock but the use of highly robust and metabolically versatile microbial biocatalysts. We tackled this challenge by means of systems metabolic engineering and validated Escherichia coli W as a promising cell factory for the production of the key building block chemical 2-ketoisovalerate (2-KIV) using whey as carbon source, a widely available and low-cost agro-industrial waste. First, we assessed the growth performance of Escherichia coli W on mono and disaccharides and demonstrated that using whey as carbon source enhances it significantly. Second, we searched the available literature and used metabolic modeling approaches to scrutinize the metabolic space of E. coli and explore its potential for overproduction of 2-KIV identifying as basic strategies the block of pyruvate depletion and the modulation of NAD/NADP ratio. We then used our model predictions to construct a suitable microbial chassis capable of overproducing 2-KIV with minimal genetic perturbations, i.e., deleting the pyruvate dehydrogenase and malate dehydrogenase. Finally, we used modular cloning to construct a synthetic 2-KIV pathway that was not sensitive to negative feedback, which effectively resulted in a rerouting of pyruvate towards 2-KIV. The resulting strain shows titers of up to 3.22 ± 0.07g/L of 2-KIV and 1.40 ± 0.04g/L of L-valine in 24h using whey in batch cultures. Additionally, we obtained yields of up to 0.81g 2-KIV/g substrate. The optimal microbial chassis we present here has minimal genetic modifications and is free of nutritional autotrophies to deliver high 2-KIV production rates using whey as a non-conventional substrate.

Application of the novel manta-ray foraging algorithm to optimize acidic peptidase production in solid-state fermentation using binary agro-industrial waste

Peptidases, which constitute about 20% of the global enzyme market, have found applications in detergent, food and pharmaceutical industries, and could be produced on a large scale using low-cost agro-industrial waste. An acidophilic Bacillus cereus strain produced acidic peptidase on binary-agro-industrial waste comprising yam peels and fish processing waste at pH 4.5 with high catalytic activity. A five-variable central composite rotatable design of a response surface methodology was used to model bioprocess conditions for improved peptidase production in solid-state fermentation. Data generated was leveraged as the basis for applying the novel Manta-ray foraging optimization-linked feed-forward artificial neural network to predict bioprocess conditions optimally. Results obtained from the optimization experiments revealed a significant coefficient of determination of 0.9885 with low-performance error. The bioprocess predicted a peptidase activity of 1035.32 U/mL under optimized conditions set as 54.8 g/100 g yam peels, 23.85 g/100 g fish waste, 0.31 g/100 g CaCl2, 47.54% (v/w) moisture content, and pH 2. Peptidase activity was improved 5-fold, and was stable for 240 min between pH 2.5 and 3.5. Michaelis-Menten kinetics revealed a Km of 0.119 mM and a catalytic efficiency of 45462.19 mM−1 min−1. The bioprocess holds promise for sustainable enzyme-driven applications.

Potential of Low Cost Agro-Industrial Wastes as a Natural Antioxidant on Carcinogenic Acrylamide Formation in Potato Fried Chips.

Acrylamide is classified as a toxic and a prospective carcinogen to humans, and it is formed during thermal process via Maillard reaction. In order to find innovative ways to diminish acrylamide formation in potato chips, several extracts of agricultural wastes including potato peels, olive leaves, lemon peels and pomegranate peels extracts were examined as a soaking pre-treatment before frying step. Total phenolic, total flavonoids, antioxidant activity, and the reduction in sugar and asparagine contents were additionally performed. Proximate composition of these wastes was found to be markedly higher in fat, carbohydrate and ash contents. Lemon peels and potato peels showed almost similar phenolic content (162 ± 0.93 and 157 ± 0.88 mg GAE /g, respectively) and exhibited strong ABTS and DPPH radical scavenging activities than the other wastes. The reduction percentage of reducing sugars and asparagine after soaking treatment ranged from 28.70 to 39.57% and from 22.71 to 29.55%, respectively. HPLC results showed higher level of acrylamide formation in control sample (104.94 mg/kg) and by using the wastes extracts of lemon peels, potato peels, olive leaves, and pomegranate peels succeeded to mitigate acrylamide level by 86.11%, 69.66%, 34.03%, and 11.08%, respectively. Thus, it can be concluded that the soaking of potato slices in the tested wastes extracts as antioxidant as pre-treatment before frying reduces the formation of acrylamide and in this way, the risks connected to acrylamide consumption could be regulated and managed.

The biobleaching potential of laccase produced from mandarin peelings: Impetus for a circular bio-based economy in textile biofinishing

The quest for circular bioeconomy has been on the rise in recent years, and it is anticipated to fulfil the environmental sustainability aspect of the sustainable development goals (SDG 2030). In this regard, our investigation attempted the biotechnological appraisal of an enzymatic derivative of bacterial (Pseudomonas sp. HRJ16) mandarin peelings (MP) fermentation as a vehicle for an environmentally benign and sustainable textile bioscouring. Production of the bacterial exudate (HRJ16 laccase) was optimized by response surface methodology (RSM), using the common low-cost agroindustrial waste (MP). HRJ16 laccase was further assessed for its advantageous biochemical and catalytic properties, and then applied in synthetic dye decolorization and denim bleaching. Results emphasized the extremotolerance of the exudate to temperature, pH, salts, cations and surfactants, when at least ca. 80 % residual activity was recollected after exposure to the different extreme operating conditions. The interesting capabilities of the HRJ16 in this study culminated in its successful bioscouring of denim fabric over 6 h and the spontaneous decolorization of the resultant effluent. This constitutive properties of HRJ16 might make it a crucial catalyst for achieving a circular bioeconomy in the textile industry.

Media Optimization by Response Surface Methodology for the Enhanced Production of Acidic Extracellular Pectinase by the Indigenously Isolated Novel Strain Aspergillus cervinus ARS2 Using Solid-State Fermentation

Pectinolytic enzymes are related enzymes that hydrolyze pectic substances. Pectinolytic enzymes are of great interest in industrial applications for softening fruits, extracting and clarifying juices, extracting olive oil, retting textile fibers, preparing gel, and isolating protoplasts. The current work presents acidic extracellular pectinase production using low-cost agro-industrial waste with the indigenously isolated novel strain Aspergillus cervinus. Two fungal isolates, ARS2 and ARS8, with maximum pectinase activity, 41.88 ± 1.57 IU/mL and 39.27 ± 1.14 IU/mL, respectively, were screened out of 27 isolates from decayed fruit peels (orange, banana, and lemon) and soil containing decomposed vegetables. The isolate ARS2, identified as Aspergillus cervinus by molecular characterization, showed the highest pectinase activity of 43.05 ± 1.38IU/mL during screening and was further used for media component screening and optimization studies. To understand their effect on pectinase activity, one-factor-at-a-time (OFAT) studies were conducted on carbon sources, nitrogen sources, and mineral salts. The OFAT results showed the highest pectinase activity for orange peel (carbon source) at 44.51 ± 1.33 IU/mL, peptone (nitrogen source) at 45.05 ± 1.04 IU/mL, and NaH2PO4 (mineral salts) at 43.21 ± 1.12 IU/mL. The most significant media components screened by the Plackett–Burman (PB) design based on the p-value, Pareto chart, and main effect plot, were orange peel (p < 0.001), peptone (p < 0.001), NaH2PO4 (p < 0.001), and KH2PO4 (p < 0.001), which were further optimized using Response Surface Methodology (RSM) and Central Composite Design (CCD). The optimization results for the media components showed a maximum pectinase activity of 105.65 ± 0.31 IU/mL for 10.63 g orange peel, 3.96 g/L peptone, 2.07 g/L KH2PO4, and 2.10 g/L NaH2PO4. Thus, it was discovered that the indigenously isolated novel strain Aspergillus cervinus ARS2 was able to successfully produce a significant amount of pectinase using agro-industrial waste. Therefore, it can be considered for the large-scale optimized production of pectinase to meet industrial demands.

Facile and sustainable modification for improving the adsorption ability of sugarcane bagasse towards cationic organic pollutants

Using low-cost agro-industrial wastes and by-products derived from lignocellulosic biomass for adsorption is considered to be an affordable and sustainable way to tackle the burning issue of cationic pollution in the water bodies, while its relatively low adsorption capability limits its large-scale application. In this study, a green, rapid, simple, and cheap method was developed by using ozone to improve the adsorption abilities of sugarcane bagasse (SB). The relationship between the chemical compositions and functional groups of SB after ozone modification and its adsorption abilities was studied. Results showed that ozone modification under very low ozone consumption (~ 1.5 wt%) could efficiently increase the pore volume, surface area, and carboxyl groups, change the chemical compositions of SB, and does not significantly change its morphology, thereby ensuring the good adsorption performance of SB and easy recycling from the water bodies. The maximum adsorption rate and equilibrium adsorption capacity of SB for positively charged methylene blue (MB) were increased about 33.3% and 11.3% than the original SB (MB concentration = 100 mg/L, SB concentration = 5 g/L, initial solution pH = 6, temperature = 30 °C). Besides, ozone-modified SB maintained its high adsorption capability even at a high NaCl concentration of 0.6 M and high pH of 9. For cationic polymer with high charge densities, the adsorption capacity of milled SB increased about 125.4%.Graphical Abstract

Pectinase from Microorganisms and Its Industrial Applications.

The utilization of microbial pectinase in different industries has been increased in its world demand. The major sources of pectinase are microorganisms mainly bacteria, fungi and yeast. The utilization of low-cost agro-industrial wastes as substrates has been preferable in pectinase production. Pectinase production faced various parameters optimization constraints such as temperature, pH and production times which are the main factors in pectinase production. The pectinase enzyme is getting attention due to its several advantages; hence, it needs to be explored further to take its maximum advantage in different industries. This review discusses the pectin substance structure, substrate for pectinase production, factors influencing pectinase production, the industrial application of microbial pectinase and also discusses challenges and future opportunities of applying microbial pectinase in industry.

Sustainable use of agro-industrial wastes as potential feedstocks for exopolysaccharide production by selected Halomonas strains.

Large quantities of waste biomass are generated annually worldwide by many industries and are vastly underutilized. However, these wastes contain sugars and other dissolved organic matter and therefore can be exploited to produce microbial biopolymers. In this study, four selected Halomonas strains, namely, Halomonas caseinilytica K1, Halomonas elongata K4, Halomonas smyrnensis S3, and Halomonas halophila S4, were investigated for the production of exopolysaccharides (EPS) using low-cost agro-industrial wastes as the sole carbon source: cheese whey, grape pomace, and glycerol. Interestingly, both yield and monosaccharide composition of EPS were affected by the carbon source. Glucose, mannose, galactose, and rhamnose were the predominant monomers, but their relative molar ratio was different. Similarly, the average molecular weight of the synthesized EPS was affected, ranging from 54.5 to 4480kDa. The highest EPS concentration (446mg/L) was obtained for H. caseinilytica K1 grown on cheese whey that produced an EPS composed mostly of galactose, rhamnose, glucose, and mannose, with lower contents of galacturonic acid, ribose, and arabinose and with a molecular weight of 54.5kDa. Henceforth, the ability of Halomonas strains to use cost-effective substrates, especially cheese whey, is a promising approach for the production of EPS with distinct physicochemical properties suitable for various applications.

Bioconversion of potato solid waste into antifungals and biopigments using Streptomyces spp.

Potato waste was processed and used as a sole substrate for simultaneously producing antifungals and biopigments using Streptomyces spp. Out of three different Streptomyces isolates, strain SO6 stood out due to its ability to produce antifungals against economically important fungal phytopathogens and intracellular biopigments using potato waste powders without additional nutrients. This strain also showed the potential to secrete a broad range of enzymes for fermentation of eight sugars that could be involved in potato waste bioconversion. The results of the fermentation assay indicated that Streptomyces sp. strain SO6 degrades potato wastes during submerged fermentation, diminishing total dry weight and increasing reducing sugars from 0.3 to 3.6 mg·mL−1 and total proteins from 70.6 to 187.7 μg·mL−1. The results showed that Streptomyces strain SO6 was able to convert the potato waste into 0.96 mg·g−1 of diffusible antifungals and 1.75 mg·g−1 of reddish-purple biopigments. On the contrary, an absence of pigment production was observed during the fermentation of the commercial medium used as reference. According to our results, replacement of commercial culture media with available low-cost agroindustrial wastes for producing bioactive chemicals is a real opportunity to enhance the Streptomyces pigment production and antibiotic sustainability with cost-competitiveness. To our knowledge, this is the first report on the simultaneous production of biopigments and diffusible antifungal antibiotics produced by Streptomyces spp. using potato solid waste as the sole nutrient source.

Improvement and Metabolomics-Based Analysis of d-Lactic Acid Production from Agro-Industrial Wastes by Lactobacillus delbrueckii Submitted to Adaptive Laboratory Evolution.

To decrease d-lactic acid production cost, sugarcane molasses and soybean meal, low-cost agro-industrial wastes, were selected as feedstock. First, sugarcane molasses was used directly by Lactobacillus delbrueckii S-NL31, and the nutrients were released from soybean meal by protease hydrolysis. Subsequently, to ensure intensive substrate utilization and enhanced d-lactic acid production from sugarcane molasses and soybean meal, adaptation of L. delbrueckii S-NL31 to substrates was performed through adaptive laboratory evolution. After two-phase adaptive laboratory evolution, the evolved strain L. delbrueckii S-NL31-CM3-SBM with improved cell growth and d-lactic acid production on sugarcane molasses and soybean meal was obtained. To decipher the potential reasons for improved fermentation performance, a metabolomics-based approach was developed to profile the differences of intracellular metabolism between initial and evolved strain. The in-depth analysis elucidated how the key factors exerted influence on d-lactic acid biosynthesis. The results revealed that the enhancement of glycolysis pathway and cofactor supply was directly associated with increased lactic acid production, and the reinforcement of pentose phosphate pathway, amino acid metabolism, and oleic acid uptake improved cell survival and growth. These might be the main reasons for significantly improved d-lactic acid production by adaptive laboratory evolution. Finally, fed-batch simultaneous enzymatic hydrolysis of soybean meal and fermentation process by evolved strain resulted in d-lactic acid levels of 112.3 g/L, with an average production efficiency of 2.4 g/(L × h), a yield of 0.98 g/g sugar, and optical purity of 99.6%. The results show the applicability of d-lactic acid production in L. delbrueckii fed on agro-industrial wastes through adaptive laboratory evolution.

Exploration of low-cost agro-industrial waste substrate for cellulase and xylanase production using Aspergillus heteromorphus

The current study was executed to explore the nutritive potential of low-cost agro-industrial waste substrates including anaerobically treated distillery spent wash (ADSW) and rice straw (RS) for enzyme production (cellulase and xylanase). The statistical model, Box–Behnken Design (BBD), was utilized to optimize the enzyme production through Aspergillus heteromorphus under liquid state bioconversion on examining the interactive interaction between substrate (ADSW), co-substrate (RS), temperature and initial pH. The BBD results revealed that the optimum levels of different factors for enzymes production were 6% ADSW, 3% RS, pH 5 and temperature 32.5 °C. The highest exoglucanase, xylanase and endoglucanase enzyme activities under optimum conditions were 6.3 IU/mL, 11.6 IU/mL and 8.1 IU/mL, respectively. The results confined that the agro-industrial waste substrate could be a cost-effective and eco-friendly alternative to produce value-added products like enzymes.

Improved biosurfactant production from Aspergillus niger through chemical mutagenesis: characterization and RSM optimization

Biosurfactants are surface-active natural polymers produced within several microorganisms and are secreted outside the cellular environment. They are the focus of modern researches due to their eco-friendly nature and high production capability using low-cost agro-industrial wastes. In this research, we have evaluated Aspergillus niger (A. niger) for its biosurfactant production potential during solid state fermentation of banana stalks powder. The native strain of A. niger produced 2.3 g/L of biosurfactant with 49.74 cm2 oil displacement, 57% emulsification index and an emulsification activity of 1.024 (OD540). Sequential mutagenesis was induced in the native strain of A. niger by exposing the strain with different concentrations of ethidium bromide (EtBr), for different time periods. Significantly higher amount of biosurfactant (3.3 g/L) was obtained from the mutant strain A. niger M2 exposed to 50 µg/10 mL of EtBr for 60 min. The screening tests revealed the improvement in oil displacement (59.81 cm2), emulsification index (62.3%) and emulsification activity (OD540, 1.262) of biosurfactant. FTIR analysis confirmed the presence of amine, amide, fatty acids and triglycerides functional groups. The maximum biosurfactant synthesizing mutant (A. niger M2) was further optimized using RSM under CCD. After optimization, the highest biosurfactant (5.50 g/L) was obtained at 35 °C temperature, 7 pH, 5.75 g substrate concentration and 168 h of overall incubation period. In conclusion, the cost-effective production of biosurfactant, along with novel structural and multifunctional characteristics, this study may be useful for different industrial and biotechnological applications.

Synergistic study of the antioxidant potential of barley waste for biodiesel

Recently, use of biodiesel as a diesel substitute has increased significantly. Currently, the biodiesel value added to diesel in Brazil is 10%. To maintain biodiesel quality during storage, antioxidants must be added. The most commonly used antioxidants are synthetic compounds. Due to the diversity of low cost agro-industrial waste with antioxidant activity, including cereal and fruit derivatives, several research studies reported the use of these waste materials as antioxidants. Barley waste (RCV) contains α-tocopherol (vitamin E), which acts as an antioxidant. Thus, this paper aims to investigate the use of RCV and citric acid as antioxidants in biodiesel. The conditions were optimized for the extraction and application of RCV in biodiesel (methyl ester soybean oil) using a 3² factorial design. RCV extracts were added during biodiesel production, which eliminates steps and improves the process. The antioxidant activity was evaluated using an accelerated oxidation method. Addition of RCV (11 g L–1) led to an induction time of 5.76 ± 0.11 h. However, addition of a blend of natural antioxidants [RCV (11 g L–1) and citric acid (0.1% w/v)] led to an increased induction time of 14.67 ± 2.10 h, which was attributed to the synergistic effect of the antioxidants.

Wheat bran as substrate for enzyme production and its application in the bio-deinking of mixed office waste (MOW) paper

Judicial utilization of various low-cost agro-industrial wastes and optimization of various process parameters can reduce production costs of enzymes. Wheat bran was found to be the best carbon source among various agro-industrial wastes explored for Penicillium citrinum NCIM-1398. Additionally, ammonium sulphate was found as the optimum nitrogen source at moisture content 70%, pH 5.5, and temperature 30 °C for enzyme production. The maximal enzyme activities of endo β-1,4-glucanase, xylanase, FPase, and amylase were 21.0 IU/gds, 3140 IU/gds, 3.59 FPU/gds, and 73.4 IU/gds, respectively. Bio-deinking of mixed office waste paper improved the pulp brightness by 9.5%, and the effective residual ink concentration were decreased by 26.3% in comparison to MOW after pulping. Similarly, dirt counts were reduced from 4880 to1360 ppm at an enzyme dose of 6.0 IU/g compared to deinking without enzyme. The strength properties of enzymatically deinked pulp such as tear index, tensile index, and burst index increased by 6.92%, 11.31%, and 7.61%, respectively, compared with the control.

Pectinolytic enzymes-solid state fermentation, assay methods and applications in fruit juice industries: a review.

A plethora of solid substrates, cultivation conditions and enzyme assay methods have been used for efficient production and estimation of polygalacturonase and pectin methylesterase enzymes. Recent developments in industrial biotechnology offer several opportunities for the utilization of low cost agro-industrial waste in Solid State Fermentation (SSF) for the pectinolytic enzyme production using fungi. Fruit waste mainly citrus fruit waste alone and along with other agro-industrial waste has been explored in SSF for enzyme production. Agro-industrial waste, due to the economic advantage of low procuring cost has been employed in SSF bioreactors for pectinolytic enzyme production. Acidic pectinases produced by fungi are utilized especially in food industries for clarification of fruit juices. This review focuses on the recent developments in SSF processes utilizing agro-industrial residues for polygalacturonase and pectin methylesterase production, their various assay methods and applications in fruit juice industries.