Fermentation Feedstock Research Articles

Enhancing photosynthetic production of glycogen-rich biomass for use as a fermentation feedstock.

Current sources of fermentation feedstocks, i.e. corn, sugar cane, or plant biomass, fall short of demand for liquid transportation fuels and commodity chemicals in the United States. Aquatic phototrophs including cyanobacteria have the potential to supplement the supply of current fermentable feedstocks. In this strategy, cells are engineered to accumulate storage molecules including glycogen, cellulose, and/or lipid oils that can be extracted from harvested biomass and fed to heterotrophic organisms engineered to produce desired chemical products. In this manuscript, we examine the production of glycogen in the model cyanobacteria, Synechococcus sp. strain PCC 7002, and subsequent conversion of cyanobacterial biomass by an engineered Escherichia coli to octanoic acid as a model product. In effort to maximize glycogen production, we explored the deletion of catabolic enzymes and overexpression of GlgC, an enzyme that catalyzes the first committed step towards glycogen synthesis. We found that deletion of glgP increased final glycogen titers when cells were grown in diurnal light. Overexpression of GlgC led to a temporal increase in glycogen content but not in an overall increase in final titer or content. The best strains were grown, harvested, and used to formulate media for growth of E. coli. The cyanobacterial media was able to support the growth of an engineered E. coli and produce octanoic acid at the same titer as common laboratory media.

Distillers' dried grains with solubles (DDGS) and its potential as fermentation feedstock.

Distillers' dried grain with solubles (DDGS) is a byproduct of bioethanol fermentation, which uses the dry milling technology for starch-rich grains such as corn, wheat, and barley. The current interest in bioethanol is increasing due to the need for renewable liquid fuels specifically in the transportation sector. Since DDGS is rich in crude protein, fat, fiber, vitamins, and minerals, it is currently used as aquaculture, livestock, and poultry feeds. In recent years, DDGS has been used as feedstock in the production of value-added products via microbial fermentation. Numerous studies reported the production organic acids, methane, biohydrogen, and hydrolytic enzymes using DDGS. While DDGS contains remarkable amounts of macronutrients, pre-treatment of DDGS is required for release of the fermentable sugars. The pre-treatment methods such as chemical, physical, and biological origin are either solely used or combined to obtain maximal yields for different applications. Therefore, this review summarizes some of the most prominent pre-treatment processes generating high fermentable sugar yields for the productions of value-added products in the last 5years. A special focus has been given to the effect of the variability of DDGS on the final product. Integration of hydrolytic enzyme production with the traditional bioethanol production facilities has been discussed for further improvement of bioethanol, methane, and biohydrogen using DDGS as fermentation feedstock.Key points• Distillers' dried grain with solubles (DDGS) has high nutritional value, but the nutritional profile is variable.• DDGS can be used for microbial fermentation feedstock to produce value-added products.• A review of the microbial products using DDGS is given for the last 5years.• DDGS has the potential to replace expensive feedstocks of value-added products.

Impact of co‐product selection on techno‐economic analyses of alternative jet fuel produced with forest harvest residuals

AbstractThis article details techno‐economic analyses for producing alternative jet fuel (AJF) at a greenfield integrated biorefinery (IBR) using softwood forest residues. The scenarios and their corresponding economic outcomes differ based on the co‐product selections. The selected technology to produce AJF uses a mild bisulfite pretreatment process to prepare the feedstock for enzymatic hydrolysis and fermentation to isobutanol, which is then upgraded to hydrocarbon ‘drop‐in’ fuels using an alcohol‐to‐jet process. The hydrocarbons are a combination of jet fuel and aviation gasoline (AvGas). The residuals are used to produce co‐products. Four co‐product scenarios are compared to quantify the impact of co‐product selection on the primary products, jet fuel, and AvGas minimum selling prices (MSPs). For the baseline (BL) scenario, residuals are burned to create steam for conversion to electricity. The excess power generated is sold at a wholesale price to the grid. The total capital investment for an IBR with a forest residue feed rate of 721 k dry metric ton year−1 is 1027 MM US$, and the AJF MSP is 2.07 US$ L−1. The BL scenario is compared with three co‐product selections: 1) liquid calcium lignosulfonate and electricity; 2) activated carbon; and 3) a combination of liquid calcium lignosulfonate and activated carbon. As anticipated, the conversion of residuals into higher value co‐products provides additional revenue to offset the production cost of hydrocarbons. The alternative co‐product scenarios reduced the predicted MSPs; however, the most cost‐competitive model, the scenario where both activated carbon and calcium lignosulfonates are produced, reduced the jet fuel MSP to 1.49 US$ L−1, a 28% reduction. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd

Microbial production of poly(3-hydroxybutyrate) from volatile fatty acids using the marine bacterium Neptunomonas concharum

Volatile fatty acids (VFAs) produced from bioresources are considered as cost-effective and environmentally friendly feedstocks for microbial fermentation. In this study, the suitability of VFAs including acetate, propionate, and butyrate as carbon sources for poly(3-hydroxybutyrate) (PHB) production by Neptunomonas concharum was assessed. In shake-flask culture, N. concharum was found to effectively convert acetate and butyrate to PHB, achieving production titers of 1.81 and 2.69 g/L, respectively. When acetate and butyrate were provided simultaneously, the strain preferentially assimilated butyrate. Unsterile cultivations were conducted to study the possibility of using butyrate in an open cultivation process. N. concharum produced 3.49 g/L PHB with a yield of 0.39 g PHB/g butyrate in shake flask cultivations. In a 5-L bioreactor, the maximal cell dry mass reached 35.07 g/L, containing 15.51 g/L PHB. These results indicate that butyrate is a promising substrate for effective PHB production by N. concharum in open and unsterile fermentation.

Production of Lactic Acid from Seaweed Hydrolysates via Lactic Acid Bacteria Fermentation

Biodegradable polylactic acid material is manufactured from lactic acid, mainly produced by microbial fermentation. The high production cost of lactic acid still remains the major limitation for its application, indicating that the cost of carbon sources for the production of lactic acid has to be minimized. In addition, a lack of source availability of food crop and lignocellulosic biomass has encouraged researchers and industries to explore new feedstocks for microbial lactic acid fermentation. Seaweeds have attracted considerable attention as a carbon source for microbial fermentation owing to their non-terrestrial origin, fast growth, and photoautotrophic nature. The proximate compositions study of red, brown, and green seaweeds indicated that Gracilaria sp. has the highest carbohydrate content. The conditions were optimized for the saccharification of the seaweeds, and the results indicated that Gracilaria sp. yielded the highest reducing sugar content. Optimal lactic acid fermentation parameters, such as cell inoculum, agitation, and temperature, were determined to be 6% (v/v), 0 rpm, and 30 °C, respectively. Gracilaria sp. hydrolysates fermented by lactic acid bacteria at optimal conditions yielded a final lactic acid concentration of 19.32 g/L.

Insights into Thermophilic Plant Biomass Hydrolysis from Caldicellulosiruptor Systems Biology.

Plant polysaccharides continue to serve as a promising feedstock for bioproduct fermentation. However, the recalcitrant nature of plant biomass requires certain key enzymes, including cellobiohydrolases, for efficient solubilization of polysaccharides. Thermostable carbohydrate-active enzymes are sought for their stability and tolerance to other process parameters. Plant biomass degrading microbes found in biotopes like geothermally heated water sources, compost piles, and thermophilic digesters are a common source of thermostable enzymes. While traditional thermophilic enzyme discovery first focused on microbe isolation followed by functional characterization, metagenomic sequences are negating the initial need for species isolation. Here, we summarize the current state of knowledge about the extremely thermophilic genus Caldicellulosiruptor, including genomic and metagenomic analyses in addition to recent breakthroughs in enzymology and genetic manipulation of the genus. Ten years after completing the first Caldicellulosiruptor genome sequence, the tools required for systems biology of this non-model environmental microorganism are in place.

Genetic engineering of transitory starch accumulation by knockdown of OsSEX4 in rice plants for enhanced bioethanol production.

Rice straw, a common agricultural waste, is used as a potential feedstock for bioethanol production. Currently, bioethanol is made mostly from the microbial fermentation of starch-containing raw materials. Therefore, genetically engineered starch-excess rice straw through interference of starch degradation as a potential strategy to enhance bioethanol production was evaluated in this study. Arabidopsis Starch Excess 4 (SEX4) encodes a chloroplast-localized glucan phosphatase and plays a role in transitory starch degradation. Despite the identification of a SEX4 homolog in rice, OsSEX4, its biological function remains uncertain. Ectopic expression of OsSEX4 complementary DNA complemented the leaf starch-excess phenotype of the Arabidopsis sex4-4 mutant. OsSEX4-knockdown transgenic rice plants were generated using the RNA interference approach. Starch accumulation was higher in OsSEX4-knockdown suspension-cultured cells, leaves, and rice straw compared with the wild type, suggesting that OsSEX4 plays an important role in degradation of transitory starch. The OsSEX4-knockdown rice plants showed normal plant growth and no yield penalty. Starch-excess OsSEX4-knockdown rice straw used as feedstock for fermentation resulted in improved bioethanol yield, with a 50% increase in ethanol production in a vertical mass-flow type bioreactor, compared with that of the wild-type straw.

Bioflocculant production using palm oil mill and sago mill effluent as a fermentation feedstock: Characterization and mechanism of flocculation

This study was conducted to examine the production of bioflocculants using agricultural wastewater as a fermentation feedstock under different temperatures and incubation times. The mechanism of flocculation was studied to gain a detailed understanding of the flocculation activity. The highest bioflocculant yield (2.03 g/L) at a temperature of 40 °C was produced in a palm oil mill effluent medium (BioF-POME). Bioflocculant produced from a fermented SME medium (BioF-SME) showed the highest activity. The flocculation tests for colour and turbidity removal from lake water indicated that BioF-SME and BioF-POME performed comparably to commercial alum. Analyses of the bioflocculants using liquid chromatography-mass spectrometry (LC-MS) found that the bioflocculants contained xylose and glucose. The mechanism study showed that flocculation occurred through charge neutralization and interparticle bridging between the bioflocculant polymer and the particles in the lake water. Thus, agricultural wastewater can be used as a fermentation feedstock for high-quality bioflocculants.

Polyhydroxyalkanoate (PHA) biosynthesis from directly valorized ragi husk and sesame oil cake by Bacillus megaterium strain Ti3: Statistical optimization and characterization

Polyhydroxyalkanoates (PHAs) signify the most promising biological substitute to petrochemical plastics. Renewable and inexpensive agro-industrial by-products can be used as potent fermentation feedstocks for sustainable PHA biosynthesis. This study aimed at using a wild type B. megaterium strain Ti3 innate hydrolytic enzyme/s for eco-friendly valorization of 16 lignocellulosic agrowastes to PHA without pretreatments. Initial hydrolytic screening PHA concentration of (0.04–0.17 g/L), highlighted the strain's metabolic versatility. Pareto ranking of Taguchi orthogonal array (TOA) established ragi husk (RH), sesame oil cake (SOC) and KH2PO4 as the most influential factors (p < 0.05). The optimized and validated Response surface methodology (RSM) model (R2, 0.979; desirability, 1) resulted in 3.8 and 3.6 fold increased PHA production, 4.3 and 3.25 fold increased PHA productivity. A positive correlation (r2, 0.5–0.97) was observed amid the producer innate hydrolytic enzymes (lipase, amylase and cellulase) and PHA production. The PHA was characterized by 1H and 13C NMR, GPC, TGA. The polymer was identified as a scl-mcl copolyester with 92% 3HB (3-hydroxybutyrate) and 8% 3HHp (3-hydroxyheptanoate) monomers by NMR. This the first report on B. megaterium self-enzyme reliant non-food agrowastes bioconversion to PHA with 3HHp (3-hydroxyheptanoate) monomers excluding precursor addition, commercial enzymes, pure carbon and nitrogen sources.

Enhancement the added value of sengon wood waste pulp as bioenergy raw material for bioethanol production

Lignocellulosic are renewable and abundant, and estimate to be produced in10-50 billion tons/year as dry matter. Cellulose component in lignocelluloses can be converted into glucose as a feedstock for ethanol fermentation. This paper contains of research results of sengon waste pulp convertion became glucose and ethanol by enzymatic hydrolysis and the purpose of this study was to obtain information on the optimum conditions of treatment to produce high ethanol content of sengon waste pulp using the Response Surface Methodology (RSM) method and high loading substrate. Response surface methodology based on a three level, three variable Central Composite Rotable Design (CCRD) was used to evaluate the interactive effect of Tween 20 concentration (0-2%), cellulase concentration (10-15 FPU/g substrate-dw) and substrate loading (20-35% dw). The results showed the highest ethanol content (15.2%) with addition 35% of substrate; 15 FPU/g substrate of enzyme and 1% Tween 20 with equations : Y = -66, 551 + 0.491X1 + 10.794 X2 – 0.025 X12 - 0.472 X22 - 1, 549 X32 + 0.065 X1X2 + 0.234 X1X3 – 0.086 X2X3. So that the use of the RSM method can know quickly which combination of treatments can produce high ethanol levels through the resulting equation. Distinctive dosages of each variable within these ranges need to be matched to each other according to resulted mathematical formula from RSM to give optimum condition points. Several optimum condition points had been validated and ethanol concentration higher than 18%v in the fermentation broth had been achieved with acuration of equation (R2 ) 0.97.

Utilization of Wheat Bran Acid Hydrolysate by Rhodotorula mucilaginosa Y-MG1 for Microbial Lipid Production as Feedstock for Biodiesel Synthesis.

The lignocellulosic hydrolysate was used as the fermentation feedstock of Rhodotorula mucilaginosa Y-MG1 for the production of microbial lipids as the potential raw material for biodiesel synthesis. On synthetic media and under nitrogen-limiting condition, the Y-MG1 strain produces 2.13 g/L of lipids corresponding to 32.7% of lipid content. This strain was able to assimilate a wide range of substrates, especially C5 and C6 sugars as well as glycerol and sucrose. Fatty acid composition shows a divergence depending on the nature of used carbon source with a predominance of oleic acid or linoleic acid. An effective hydrolysis process, based on diluted acid treatment, was established for providing the maximum of fermentable sugars from different characterized lignocellulosic wastes. The highest yield of reducing sugars (56.6 g/L) could be achieved when wheat bran was used as the raw material. Hydrolysate detoxification step was not required in this study since the Y-MG1 strain was shown to grow and produce lipids in the presence of inhibitors and without the addition of external elements. Operating by controlled fed-batch fermentation yielded a dry biomass and oil yield of up to 11 g/L and 38.7% (w/w), respectively. The relative fatty acid composition showed the presence of increased levels of monounsaturated (66.8%) and saturated (23.4%) fatty acids in lipids of Y-MG1 grown on wheat bran. The predictive determination of biodiesel properties suggests that this oil may effectively be used for biodiesel production.

Lipid and carotenoid production from wheat straw hydrolysates by different oleaginous yeasts

This work aimed to support the development of a new process for the production of lipids and carotenoids by oleaginous yeasts using both cellulosic and hemicellulosic fractions of biomass as feedstock for fermentation. The hypothesis behind this idea is that this strategy could lead to a sustainable pathway to produce these valuable components with potential to reduce the production costs. For the experiments, six oleaginous yeasts were initially cultivated in synthetic media containing glucose or xylose as carbon sources and different carbon to nitrogen ratios in order to identify the top producers. Rhodosporidium toruloides NRRL Y-1091 and Lipomyces starkeyi NRRL Y-1389 produced the highest amount of carotenoids and lipids, respectively. Then, the performance of these two strains when cultivated in wheat straw cellulosic and hemicellulosic hydrolysates was assessed. Detoxification of the cellulosic and hemicellulosic hydrolysates with activated charcoal removed 87.80% and 77.17% of inhibitors, respectively, and significantly improved the performance of the two yeasts. The highest concentration of lipids, 3.99 ± 0.35 g/L, was obtained by cultivating L. starkeyi in washed cellulosic hydrolysate; while the highest production of carotenoids, 24.58 ± 1.88 mg/L, was obtained by cultivating R. toruloides in decolorized cellulosic hydrolysate. Increasing the tolerance of oleaginous yeasts to inhibitors resulting from biomass pretreatment and/or using cost-effective detoxification methods were identified as key parameters for further development of this process at commercial scale.

Optimization of process parameters for bioethanol production from oil palm frond juice by Saccharomyces cerevisiae using response surface methodology as a tool

The aim of this research was to investigate the effect of temperature, medium initial pH and rotation rate on the production of bioethanol from OPF juice without nutrient and nitrogen source supplementation using Saccharomyces cerevisiae Kyokai No. 7 (ATCC 26622). A five-level-three-factor central composite design (CCD) was employed in this study and the central point of each process variable was chosen based on the best condition obtained from the one-factor-at-time (OFAT) method. The parameters ranges were set as follows; medium initial pH (5-9), temperature (27.5-37.5°C) and rotation rate (80-120 rpm). Bioethanol and residual sugars concentration were determine using High Performance Liquid Chromatography (HPLC). The optimum conditions for bioethanol production from OPF juice were achieved at medium initial pH (6.62), rotation rate (96.51 rpm) and temperature (33.03°C). Based on the validation experiment, the optimum bioethanol yield was 0.50 ±0.02 g/g sugars and this value was in close agreement with the model prediction where the difference was only 4.17%. Under the optimal conditions, the bioethanol yield obtained was 47.06% higher compared with non-optimized condition. The promising yield obtained in this study suggests that OPF juice can be used as a renewable and complete fermentation feedstock for bioethanol production.

Bioprocess development for the production of novel oleogels from soybean and microbial oils.

This study presents the production of novel oleogels via circular valorisation of food industry side streams. Sugarcane molasses and soybean processing side streams (i.e. soybean cake) were employed as fermentation feedstocks for the production of microbial oil. Fed-batch bioreactor fermentations carried out by the oleaginous yeast Rhodosporidium toruloides led to the production of 36.9 g/L total dry weight with an intracellular oil content of 49.8% (w/w) and 89.4 μg/g carotenoids. The carotenoid-rich microbial oil and soybean oil were evaluated as base oils for the production of wax-based oleogels. The wax esters, used as oleogelators, were produced via enzymatic catalysis, using microbial oil or soybean fatty acid distillate as raw materials. All oleogels presented a gel-like behaviour (G' > G″). However, the highest G' was determined for the oleogel produced from soybean oil and microbial oil-wax esters, which indicated a stronger network. Thermal analysis showed that this oleogel had a melting temperature profile up to 35 °C, which is favorable for applications in the confectionery industry. Also, texture analysis demonstrated that soybean oil-microbial oil wax oleogel was stable (1.9-2.2 N) within 30-days storage period. This study showed the potential of novel oleogels production through the development of bioprocesses based on the valorisation of various renewable resources.

Rapeseed meal hydrolysate as substrate for microbial astaxanthin production

Rapeseed meal, a by-product of oil processing industry, was evaluated as a substrate for astaxanthin production by the yeast Xanthophyllomyces dendrorhous DSMZ 5626. Four commercial enzymes were tested at different concentrations (1–15%, v/v) for their ability to break down the cellulosic and hemicellulosic compounds of rapeseed meal into fermentable sugars. Viscozyme® L and cellulase demonstrated the highest glucose recovery yields (47–52%, w/w for 15% (v/v) of enzyme loading) with 7–11 g/l of net glucose released in the hydrolysates. Pectinase and Accellerase® hydrolysates supported the best cell growth and astaxanthin production in batch shake flask cultures, with maximum biomass of 26 g/l and 15 g/l, respectively, and astaxanthin yields (YP/X) of 258–332 μg per g of biomass. In batch bioreactor trials, pectinase hydrolysates resulted in high biomass (42 g/l) and astaxanthin production (11 mg/l) aided by the presence of glycerol (originating from the enzyme formulation) which served as additional energy and carbon source. Finally, simple glass beads disruption lead into satisfactory astaxanthin extraction (95%, w/w) in acetone. The findings of this study generate knowledge towards scale-up potential of microbial astaxanthin production using rapeseed meal hydrolysate as fermentation feedstock.

Effect of storage time and temperature on hydrogen fermentation of food waste

Practically, before being fed to the treatment plant, food waste (FW) is stored for up to a week in a storage tank under ambient temperature condition, which would have an impact on the bioenergy yield. In the present work, FW was stored at different temperatures (5 °C, 20 °C, and 35 °C) for 0 d, 1 d, and 2 d, and it was used as a feedstock for mesophilic H2 fermentation. H2 production curves were divided by three groups, finally attaining 1.7–1.8 mol H2/mol hexoseadded, 1.4–1.5 mol H2/mol hexoseadded, and 1.2 mol H2/mol hexoseadded, achieved from the (fresh, FW stored at 5 °C), (FW stored at 20 °C, and 35 °C for 1 d), and (FW stored at 35 °C for 2 d), respectively. The different performance was attributed to the growth of indigenous lactic acid bacteria such as Lactobacillus and Weissella during storage under high temperature condition. In addition, it was found that the activity of homoacetogenic reaction (R17, 4H2 + CO2 → Acetate) calculated by establishing metabolic flux balance was different depending on the H2 production performance. The flux of R17 ranged 0.03–0.06 under low H2 yield achieved conditions, while it increased to 0.10–0.17 those showing low H2 yields.

Enhanced co-production of biohydrogen and algal lipids from agricultural biomass residues in long-term operation

This study evaluates a two-stage process by dark fermentation and microalgal cultivation for hydrogen and lipid production from different agricultural biomass residues, such as corn cob, corn stalk, rice straw and wheat straw. Results indicate that corn stalk was the best fermentation feedstock for hydrogen production and the highest accumulative hydrogen volume of 762.3 mL L−1 was obtained in batch mode. Dark fermentative effluent from corn stalk was rich in acetate and butyrate, and was favorable to lipid production. The maximum algal biomass and total lipid content reached 1461.1 mg L−1 and 35.2%, respectively. Meanwhile, the energy conversion efficiency in two-stage cultivation significantly increased from 5.78% to 16.96%. The system was stable and effective in long-term operation, and the average hydrogen production rate of 811.1 mL L−1 d−1 and lipid concentration of 588.5 mg L−1 were achieved. This study provides a promising process for enhancing energy production from agricultural wastes.

The development of a biorefining strategy for the production of biofuel from sorghum milling waste

The potential of using sorghum milling waste for the development of a biorefining strategy for the production of bioethanol was investigated. Both red and white sorghum were processed using a traditional Nigerian wet-milling process to sorghum flour. The sorghum milling waste, sorghum bran, was hydrolysed using both enzymatic and dilute acid hydrolysis to produce a generable fermentation feedstock. The hydrolysates were subsequently investigated for fermentative biofuel production. Following a hydrolysis step, a medium containing ˜61 g/L glucose was obtained. Trace presence of inhibitors was detected in the hydrolysates and sufficient nitrogen content to support microorganism growth and bioethanol production. In test bioethanol production experiments using the sorghum milling waste derived hydrolysates only, 24.35 g/L bioethanol was produced by a yeast Kluyveromyces marxianus, equivalent to a yield of 0.15 g bioethanol per g of sorghum milling waste.

Assessing the environmental sustainability of glucose from wheat as a fermentation feedstock

In recent years, the need to substitute fossil fuels with renewable biomass has been a key driver in the development of the biorefinery concept. One of the possible routes towards the development of bioproducts under this scheme is through a sugar intermediate. Sugars, such as glucose, can be produced through starch crops, for instance wheat. While there are many environmental assessment studies that consider sugar as a platform for biofuel production, the main focus is on the end product of the value chain (typically bioethanol), but not on sugars as the basic feedstock. Taking the bottom-up perspective as a roadmap, the assessment of technological, economic and environmental barriers in the biorefinery scheme must take into account the sustainability of sugar production with the aim of improving its current framework or finding novel technologies. This study investigates the environmental sustainability of wheat cultivation and grain processing in different European countries by applying the life cycle assessment (LCA) methodology with a cradle to gate approach. Moreover, 1 kg of glucose at the factory gate has been considered as a functional unit for reporting the environmental results. The chosen impact categories are climate change (CC), particular matter (PM), human toxicity (HT), freshwater eutrophication (FE), terrestrial eutrophication (TE), acidification (AC) and abiotic depletion (AD). Mass and economic allocations are evaluated as the processing of grain wheat generates different valuable by-products, namely wheat bran, gluten meal and gluten feed. The results show that agricultural activities play an important role in the environmental impacts, predominantly due to the production of agrochemicals and field emissions derived from fertilisation. In addition, the choice of allocation has a greater environmental influence (both positive or negative) on the by-products than the main product under investigation.

Rapid detection of carbon-nitrogen ratio for anaerobic fermentation feedstocks using near-infrared spectroscopy combined with BiPLS and GSA.

Near-infrared spectroscopy (NIRS) is an efficient method for detecting the content of carbon and nitrogen in many materials, which solves the problems of the time-consuming and high-cost traditional chemical analysis method. To quickly detect the carbon-nitrogen ratio (C/N) for the anaerobic fermentation (AF) feedstock using NIRS, a genetic simulated annealing algorithm (GSA) is presented based on a genetic algorithm combined with a simulated annealing algorithm. By combining GSA with backward interval partial least squares (BiPLS), we construct a BiPLS-GSA algorithm to optimize the characteristic wavelength variables of NIRS; this algorithm significantly reduced the number of wavelength variables involved in modeling and effectively improved the detection accuracy and efficiency of the model. The determination coefficients, root mean squared error, mean relative error (MRE) and residual predictive deviation for the validation set in the BiPLS-GSA regression model were 0.9067, 7.6676, 5.5274%, and 3.5626, respectively. Meanwhile, compared to the entire spectrum model, the MRE was decreased by 16.54% in the BiPLS-GSA-based model. The research in this paper improves the adaptability of the prediction model based on optimizing sensitive wavelength variables for C/N, which provides a new way for rapid and accurate measurement of the C/N of AF feedstock.