•Availability and cultivation practices of paddy rice.•Overview on the production of value added products from rice straw.•Recent developments in rice straw based biorefinery.
The biorefinery ...approach for the production of fuels and chemicals is gaining more and more attraction in recent years. The major advantages of biorefineries are the generation of multiple products with complete utilization of biomass with zero waste generation. Moreover the process will be economically viable when it targets low volume high value products in addition to high volume low value products like bioethanol. The present review discuss about the potential of rice straw based biorefinery. Since rice is a major staple food for many Asian countries, the utilization of the rice straw residue for fuel and chemicals would be very economical. The review focuses the availability and the potential of this residue for the production of fuel and other high value chemicals.
Applications of Microbial Enzymes in Food Industry Raveendran, Sindhu; Parameswaran, Binod; Ummalyma, Sabeela Beevi ...
Food technology and biotechnology,
01/2018, Volume:
56, Issue:
1
Journal Article
Peer reviewed
Open access
The use of enzymes or microorganisms in food preparations is an age-old process. With the advancement of technology, novel enzymes with wide range of applications and specificity have been developed ...and new application areas are still being explored. Microorganisms such as bacteria, yeast and fungi and their enzymes are widely used in several food preparations for improving the taste and texture and they offer huge economic benefits to industries. Microbial enzymes are the preferred source to plants or animals due to several advantages such as easy, cost-effective and consistent production. The present review discusses the recent advancement in enzyme technology for food industries. A comprehensive list of enzymes used in food processing, the microbial source of these enzymes and the wide range of their application are discussed.
Cell immobilisation provides the opportunity to reduce the cost of producing bioethanol from lignocellulosic biomass such as oilseed rape (OSR) straw, in addition to enhancing operational stability. ...Bioethanol fermentation of OSR straw hydrolysate by free and immobilised Saccharomyces cerevisiae was studied. Cells were either entrapped in alginate beads or Lentikat® discs or immobilised as a biofilm on spent grains, Leca, or reticulated foam. The overall aims of the research were to compare bioethanol yields produced from free and immobilised systems, and to identify the most suitable immobilisation technique in terms of bioethanol yield and longevity of the immobilised cell system. Cell entrapment in alginate beads and Lentikat® discs resulted in significantly higher bioethanol yields compared to when cells were free in suspension or immobilised as a biofilm on a support material. The maximum amount of bioethanol produced by cells immobilised in alginate beads and Lentikat® discs were 169.26 ± 0.24 and 165.13 ± 0.67 g bioethanol kg−1 OSR straw after 3 h and 7 h of fermentation, respectively. Due to the high mechanical stability and bioethanol yield, immobilisation of S. cerevisiae in Lentikat® discs was considered the most appropriate immobilisation technique for bioethanol production.
► Bioethanol production from OSR straw using free and immobilised yeast cells. ► Entrapment mode of immobilisation was studied using alginate and Lentikat®. ► Biofilm mode of immobilisation studied using spent grains, reticulated foam, Leca. ► Cells immobilised in Lentikat® was superior to other supports used in this study.
•Continuous bioethanol production from OSR straw hydrolysate was investigated.•Maximum volumetric productivity of 12.88gL−1h−1 was achieved.•Energy recovery from bioethanol represents only 35% of ...biomass energy content.
The aim of the study was to evaluate continuous bioethanol production from oilseed rape (OSR) straw hydrolysate using Saccharomyces cerevisiae cells immobilised in Lentikat® discs. The study evaluated the effect of dilution rate (0.25, 0.50, 0.75 and 1.00h−1), substrate concentration (15, 22, 40 and 60gL−1) and cell loading (0.03, 0.16 and 0.24gd.c.w.mL−1 Lentikat®) on bioethanol production. Volumetric productivity was found to increase with increasing substrate concentration from 15gL−1 to 60gL−1. A maximum volumetric productivity of 12.88gL−1h−1 was achieved at a substrate concentration of 60gL−1 and at a dilution rate of 0.5h−1. An overall mass balance for bioethanol production was created to determine the energy recovery from bioethanol and concluded that a biorefinery approach might be the most appropriate option for maximising the energy recovery from OSR straw.
A novel ultrasound-assisted alkali pretreatment strategy was developed which could effectively remove lignin and hemicelluloses and improve the sugar yield from chili post harvest residue. ...Operational parameters that affect the pretreatment efficiency were studied and optimized. Inhibitor analysis of the hydrolyzate revealed that major fermentation inhibitors like furfural, 5-hydroxymethyl furfural as well as organic acids like citric acid, succinic acid and propionic acid were absent. Hence fermentation can be carried out without detoxification of the hydrolyzate. Changes in structural properties of the biomass were studied in relation to the pretreatment process using Scanning Electron Microscopy (SEM) and the changes in chemical composition were also monitored. The biomass pretreated with the optimized novel method could yield 0.428g/g of reducing sugars upon enzymatic hydrolysis. The hydrolyzate obtained by this novel pretreatment strategy was found to be suitable for bioethanol and xylanase production.
The challenge associated with cellulosic ethanol production is maximizing sugar yield at low cost. Current research is being focused to develop a pretreatment method to overcome biomass recalcitrance ...in an efficient way. This review is focused on two major pretreatments: dilute acid (DA) and ammonia fiber explosion (AFEX) pretreatment of corn stover and how these pretreatment cause morphological and chemical changes to corn stover in order to overcome the biomass recalcitrance. This review highlights the key differences of these two pretreatments based on compositional analysis, cellulose and its crystallinity, morphological changes, structural changes to lignin, enzymatic reactivity and enzyme adsorption onto pretreated solids and finally cellulosic ethanol production from the hydrolysate of DA and AFEX treated corn stover. Each stage of the process, AFEX pretreated corn stover was superior to DA treated corn stover.
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•Various inoculum to biomass ratios were taken to monitor the biogas production by anaerobic digestion.•The biogas production was higher in water hyacinth and salvinia produced ...maximum methane.•The VFA did not inhibit the anaerobic digestion.•Multiple linear regression was performed as a predictive analysis.
The aim of the study was to explore the role of volatile fatty acids in batch scale anaerobic digestion of two potential aquatic weeds (water hyacinth and salvinia), as substrates for anaerobic digestion. Inoculum (cow dung) to biomass (aquatic weeds) ratio of 0.25:1, 0.5:1, 1:1 and 3:1 were taken and monitored in a 2 L digester for 30 days. The maximum amount of biogas produced for was 406 L kg−1 VS for water hyacinth in 0.5:1 and 330 L kg−1 VS for salvinia in 1:1 and 3:1 ratio for both. The total VFA for water hyacinth and salvinia were 410 mgL−1 & 365 mg L−1, 424 mg L−1 & 316 mg L−1, 272 mg L−1 & 234 mg L−1 and 158 mg L−1 & 94 mg L−1 in 0.25:1, 0.5:1, 1:1 and 3:1 ratios respectively. Multiple linear regression was performed to find the relationship between the methane from biogas, total VFA, acetic acid and propionic acid for enhanced biogas production. It was observed that total VFA significantly influenced methane content in 1:1 (SC) and 3:1 (WC).
Seven isolates from spoiled fruits and vegetables were screened for pectinase production using pectin agar plates and the most efficient bacterial strain, MPTD1, was identified as
Optimisation of ...various process parameters was done using Plackett-Burman and Box-Behnken designs and it was found that parameters like yeast extract, K
HPO
, incubation time, NaNO
and KCl have a negative impact on pectinase production. Parameters like pH and MgSO
and pectin mass fractions have a positive impact on pectinase production. The maximum obtained enzyme activity was 2.43 (μM/mL)/min. This is the first report on pectinase production by
.
Surfactants play major role in the delignification of lignocellulosic biomass. Surfactant-assisted hydrothermal pretreatment was evaluated for chili post-harvest residue. Maximum reducing sugar yield ...of 0.445 g per g of dry biomass (g/g) was obtained when surfactant PEG 6000 was used. Compositional analysis revealed an efficient removal of lignin and hemicelluloses from the pretreated biomass. Fermentation inhibitors such as furfural, 5-hydroxymethylfurfural and organic acids were absent in the hydrolyzate. After pretreatment, the biomass can be directly hydrolyzed without any neutralization, washing and drying, and the hydrolyzate is devoid of major fermentation inhibitors. Fermentation with
Saccharomyces cerevisiae
yielded 1.84% of ethanol with a fermentation efficiency of 63.88%.
α-Amylases is one of the most important industrial enzyme which contributes to 25% of the industrial enzyme market. Though it is produced by plant, animals and microbial source, those from microbial ...source seems to have potential applications due to their stability and economic viability. However a large number of α-amylases from different sources have been detailed in the literature, only few numbers of them could withstand the harsh industrial conditions. Thermo-stability, pH tolerance, calcium independency and oxidant stability and starch hydrolyzing efficiency are the crucial qualities for α-amylase in starch based industries. Microbes can be genetically modified and fine tuning can be done for the production of enzymes with desired characteristics for specific applications. This review focuses on the native and recombinant α-amylases from microorganisms, their heterologous production and the recent molecular strategies which help to improve the properties of this industrial enzyme.
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