Rice straw fermentation using lactic acid bacteria

Effects of Flammulina velutipes mushroom residues on growth performance, apparent digestibility, serum biochemical indicators, rumen fermentation and microbial of Guizhou black goat

Introduction

The primary objective of the current study was to evaluate the effects of Flammulina velutipes mushroom residue (FVMR) in a fermented total mixed ration (FTMR) diet on the fattening effect and rumen microorganisms in Guizhou black male goats.

Methods

A total of 22 Guizhou black male goats were allocated into two groups using the Randomized Complete Block Design (RCBD) experimental design. The average initial weight was 22.41 ± 0.90 kg and with 11 goats in each group. The control group (group I) was fed the traditional fermentation total mixed ration (FTMR) diet without FVMR. Group II was fed the 30% FVMR in the FTMR diet.

Results

The results showed that compared with group I, the addition of FVMR in the goat diet could reduce the feed cost and feed conversion ratio (FCR) of group II (p < 0.01). Notably, the apparent digestibility of crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), and dry matter (DM) were higher in group II (p < 0.01). The levels of growth hormone (GH), immunoglobulin A (IgA), and immunoglobulin M (IgM) in group II were higher than that of group I (p < 0.01), which the level of glutamic oxalacetic transaminase (ALT) and interleukin-6 (IL-6) was noticeably lower than that of group I (p < 0.01). 30% FVMR in FTMR diets had no effect on rumen fermentation parameters and microbial composition at the phylum level of Guizhou black male goats (p > 0.05). However, at the genus level, the relative abundance of bacteroidal_bs11_gut_group, Christensenellaceae_R-7_group and Desulfovibrio in group II was lower than in group I (p < 0.05), and the relative abundance of Lachnospiraceae_ND3007_group was higher than in group I (p < 0.01).

Discussion

In conclusion, the results of the current study indicated that 30% FVMR in the FTMR diet improves rumen fermentation and rumen microbial composition in Guizhou black male goats, which improves growth performance, apparent digestibility, and immunity.

Effect of Fibrolytic Enzymes, Cellulolytic Fungi and Lactic Acid Bacteria on Fermentation Characteristics, Structural Carbohydrate Composition and In Vitro Digestibility of Rice Straw Silage

This study aimed to investigate the effect of fibrolytic enzymes, cellulolytic fungi and lactic acid bacteria on the fermentation quality, structural carbohydrate composition and in vitro digestibility of rice straw silage. This experiment followed a completely randomised block design; four treatments were designed: (1) distilled water (control, CON); (2) fibrolytic enzymes (2.0 g/kg fresh weight (FW), E); (3) Trichoderma reesei (4400 U/kg FW, F); (4) Enterococcus faecium Y83 (1 × 106 cfu/g FW, Y83). All additives were diluted with distilled water and sprayed onto the rice straw (20 mL/kg FW). The rice straw was placed into a laboratory silo (10 L) after uniformly mixing and stored at ambient temperature (17–22 °C) ensiling for 3, 7, 14, 30 and 60 days. The fermentation quality in treated silages was improved compared to the CON, as indicated by lower pH, propionic acid, acetic acid and ammonia nitrogen (NH3-N) contents. Furthermore, Y83 had the lowest (p < 0.05) pH and highest (p < 0.05) lactic acid content after 60 days of ensiling. Y83 significantly (p < 0.05) decreased the neutral detergent fibre content compared with CON, E and F. In addition, E and Y83 had significantly (p < 0.05) higher in vitro dry matter digestibility and in vitro neutral detergent fibre digestibility than CON and F. Overall, Y83 can be used as a promising inoculant for improving the fermentation quality of rice straw silage.

Valorization of mushroom by-products: a review

With the rapid growth of the global economy and the global population, the production of solid waste has increased remarkably. Mushrooms are gaining popularity among researchers for their ability to turn waste into nutrients. However, a large number of by-products are produced during the industrial processing of mushrooms. Traditional waste management, focusing on the utilization and disposal of mushroom by-products, has attracted the attention of researchers. Meanwhile, the circular economy has become a multidisciplinary research field, and the valorization of mushroom by-products is a very important part of circular economy research. Various mushroom by-products of mushroom are reviewed in this paper. By-products are used in food as raw materials or functional components, in livestock and poultry feed after grinding/fermentation, and as electrochemical materials and papermaking materials. The by-products can also be used to produce ethanol and other biological sources of energy, as absorbing substances in sewage treatment, and as fertilizer in soil amendment. Mushroom processing by-products can be applied in various fields. To improve production efficiency, new extraction technology (including supercritical fluid technology and microwave extraction technology) can be adopted to increase the bioactive substance content in the by-products. Choosing appropriate processing temperature, time, and other processing conditions can also enhance product quality. Finally, more research is needed on the cost-effective utilization of the by-products and the feasibility of industrialization. © 2022 Society of Chemical Industry.

Use of Starter Cultures in Foods from Animal Origin to Improve Their Safety

Starter cultures can be defined as preparations with a large number of cells that include a single type or a mixture of two or more microorganisms that are added to foods in order to take advantage of the compounds or products derived from their metabolism or enzymatic activity. In foods from animal origin, starter cultures are widely used in the dairy industry for cheese, yogurt and other fermented dairy products, in the meat industry, mainly for sausage manufacture, and in the fishery industry for fermented fish products. Usually, microorganisms selected as starter culture are isolated from the native microbiota of traditional products since they are well adapted to the environmental conditions of food processing and are responsible to confer specific appearance, texture, aroma and flavour characteristics. The main function of starter cultures used in food from animal origin, mainly represented by lactic acid bacteria, consists in the rapid production of lactic acid, which causes a reduction in pH, inhibiting the growth of pathogenic and spoilage microorganisms, increasing the shelf-life of fermented foods. Also, production of other metabolites (e.g., lactic acid, acetic acid, propionic acid, benzoic acid, hydrogen peroxide or bacteriocins) improves the safety of foods. Since starter cultures have become the predominant microbiota, it allows food processors to control the fermentation processes, excluding the undesirable flora and decreasing hygienic and manufacturing risks due to deficiencies of microbial origin. Also, stater cultures play an important role in the chemical safety of fermented foods by reduction of biogenic amine and polycyclic aromatic hydrocarbons contents. The present review discusses how starter cultures contribute to improve the microbiological and chemical safety in products of animal origin, namely meat, dairy and fishery products.

Biochar from pyrolyzed Tibetan Yak dung as a novel additive in ensiling sweet sorghum: An alternate to the hazardous use of Yak dung as a fuel in the home

Yak dung is used as fuel in Tibetan homes; however, this use is hazardous to health. An alternative use of the dung that would be profitable and offset the loss as a fuel would be very beneficial. Sweet sorghum silage with yak dung biochar as an additive was compared with a control silage with no additives and three silages with different commercial additives, namely Lactobacillus buchneri, Lactobacillus plantarum and Acremonium cellulase. Biochar-treated silage had a significantly greater concentration of water-soluble carbohydrates than the other silages (76 vs 12.4-45.8 g/kg DM) and a greater crude protein content (75.5 vs 61.4 g/kg DM), lactic acid concentration (40.7 vs 27.7 g/kg DM) and gross energy yield (17.8 vs 17.4 MJ/kg) than the control silage. Biochar-treated and control silages did not differ in in vitro digestibility and in total gas (507 vs 511 L/kg DM) and methane production (57.9 vs 57.1 L/kg DM). Biochar inhibited degradation of protein and water-soluble carbohydrates and enhanced lactic acid production, which improved storability of feed. It was concluded that yak dung biochar is an efficient, cost-effective ensiling additive. The profit could offset the loss of dung as fuel and improve the health of Tibetan people.

Effect of Lactic Acid Bacteria on the Nutritive Value and In Vitro Ruminal Digestibility of Maize and Rice Straw Silage

A study was conducted to determine the effects of lactic acid bacteria (LAB) on nutritive value and in vitro rumen digestibility of maize and rice straw silages. Two identical experiments were carried out for each of the two silages. A total of five treatments were used for each experiment: (1) negative control (NC); (2) positive control (PC); (3) Lactobacillus plantarum (LPL); (4) L. paracasei (LPA); and (5) L. acidophilus (LA). Each treatment was then divided into four ensiling periods: 3, 7, 20, and 40 days with three replications. The LPL treatment had significantly higher dry matter (DM), lower ammonia-N, and a lower number of fungi on maize silage after 40 days (p < 0.05). On the other hand, the LA treatment increased DM and CP content, reduced NDF and ADF contents compared to NC, and also produced more lactic acid compared to the other LAB-treated rice straw silages. Results of the in vitro rumen fermentation of maize silages showed no significant differences in DMD after LAB inoculation. However, higher DMD and ruminal ammonia-N were shown by rice straw ensiled with L. acidophilus. In conclusion, silage additives, which could improve the ensiling process of maize and rice straw, appeared to be different and substrate specific.

Cellulase interacts with Lactobacillus plantarum to affect chemical composition, bacterial communities, and aerobic stability in mixed silage of high-moisture amaranth and rice straw

The objective was to evaluate effects of Lactobacillus plantarum and/or cellulase on fermentation, aerobic stability and bacterial community of mixed high-moisture amaranth (AF) and rice straw (RS) silage. The mixtures were treated with no addition (C), L. plantarum (L), cellulase (F) and their combination (LF). Additives increased the abundances of Lactobacillus and reduced the abundances of Weissella, Pediococcus, Lactococcus, decreased pH, acetic acid, ammonia nitrogen and increased lactic acid concentration as compared to C silage over the ensiling period. The LF silage had the highest lactic acid concentration among all silages over the 7 d of ensiling and also the lowest abundance of Enterobacteriaceae over 30 d of ensiling. Aerobic spoilage occurred in C and LF silages after 2 d of aerobic exposure, whereas the L and F silages remained stable > 4 d. In conclusion, silage treated with LF showed best silage quality.

Interaction effect of silo density and additives on the fermentation quality, microbial counts, chemical composition and in vitro degradability of rice straw silage

This research evaluated the effect of molasses (M), cellulosic enzymes (E) and lactic acid bacteria (LAB) alone or in combination (M + LAB and E + LAB) on the fermentation quality, microbial counts, chemical composition and in vitro degradability of rice straw silages in different silo densities (200, 300, 400 and 500 kg/m³). The M or E groups alone increased the dry matter (DM) losses at low silo densities. Acetic acid produced by LAB-related groups significantly inhibited yeast and mould at the silo density of 300 kg/m³. Under high silo densities (>400 kg/m³), LAB-related additives significantly improved the fermentation quality and reduced the DM losses. The use of E + LAB further improved the in vitro degradability of rice straw silages at high silo densities. In conclusion, higher silo density and appropriate complex additives were of great significance to improve the quality of rice straw silage.

Effects on microbial diversity of fermentation temperature (10°C and 20°C), long-term storage at 5°C, and subsequent warming of corn silage

Objective

To evaluate the effects on microbial diversity and biochemical parameters of gradually increasing temperatures, from 5°C to 25°C on corn silage which was previously fermented at ambient or low temperature.

Methods

Whole-plant corn silage was fermented in vacuum bag mini-silos at either 10°C or 20°C for two months and stored at 5°C for two months. The mini-silos were then subjected to additional incubation from 5°C to 25°C in 5°C increments. Bacterial and fungal diversity was assessed by polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE) profiling and biochemical analysis from mini-silos collected at each temperature.

Results

A temperature of 10°C during fermentation restricted silage fermentation compared to fermentation temperature of 20°C. As storage temperature increased from 5°C to 25°C, little changes occurred in silages fermented at 20°C, in terms of most biochemical parameters as well as bacterial and fungal populations. However, a high number of enterobacteria and yeasts (4 to 5 log₁₀ colony forming unit/g fresh materials) were detected at 15°C and above. PCR-DGGE profile showed that Candida humilis predominated the fungi flora. For silage fermented at 10°C, no significant changes were observed in most silage characteristics when temperature was increased from 5°C to 20°C. However, above 20°C, silage fermentation resumed as observed from the significantly increased number of lactic acid bacteria colonies, acetic acid content, and the rapid decline in pH and water-soluble carbohydrates concentration. DGGE results showed that Lactobacillus buchneri started to dominate the bacterial flora as temperature increased from 20°C to 25°C.

Conclusion

Temperature during fermentation as well as temperature during storage modulates microorganism population development and fermentation patterns. Silage fermented at 20°C indicated that these silages should have lower aerobic stability at opening because of better survival of yeasts and enterobacteria.

Biotechnological valorization of agro industrial and household wastes for lactic acid production

Lactic acid (LA) is an organic compound used in several industries, such as food, textile, chemical, and pharmaceutical. The global interest  in  this  product  is  due  to  its  use  for  the  synthesis  of  numerous  chemical  compounds,  including  polylactic  acid,  a  biode-gradable thermoplastic and substitute for petroleum-derived plastics. An in-depth overview of the use of industrial and household wastes as inexpensive substrates in order to reduce the cost of LA production is presented. A review is carried out of the biotech-nological aspects that must be taken into account when using some wastes with high transformation potential to produce LA in a submerged  culture,  as  well  recommendations  for  their  use.  The  advantages  and  disadvantages  of  different  types  of  treatments used for the transformation of waste into suitable substrates are considered. Several methods of fermentation, as well as genetic strategies for increasing the production, are summarized and compared. It is expected that in a few years there will be many ad-vances in these areas that will allow greater large-scale production of LA using agroindustrial or household wastes, with potential positive economic and environmental impact in some regions of the planet.

Effect of ensiling and silage additives on biogas production and microbial community dynamics during anaerobic digestion of switchgrass

Silage processing has a crucial positive impact on the methane yield of anaerobic treated substrates. Changes in the characteristics of switchgrass after ensiling with different additives and their effects on methane production and microbial community changes during anaerobic digestion were investigated. After ensiling (CK), methane yield was increased by 33.59% relative to that of fresh switchgrass (FS). In comparison with the CK treatment, methane production was improved by 17.41%, 13.08% and 8.72% in response to ensiling with LBr+X, LBr and X, respectively. A modified Gompertz model predicted that the optimum treatment was LBr+X, with a potential cumulative methane yield of 178.31mL/g total solids (TS) and a maximum biogas production rate of 44.39mL/g TS·d. Firmicutes and Bacteroidetes were the predominant bacteria in FS and silage switchgrass; however, the switchgrass treated with LBr+X was rich in Synergistetes, which was crucial for methane production.

Effect of different levels of corn steep liquor addition on fermentation characteristics and aerobic stability of fresh rice straw silage

The object of this study was to determine the proper mixing ratio of fresh rice straw to corn steep liquor (CSL) to obtain a high protein content silage feed. The following experimental silages were generated: the control (C1), composed of fresh rice straw without CSL additive, mixed with CSL in the ratios of 4:1 (C4), 3:1 (C3) and 2:1 (C2). Lactic acid bacteria (LAB) inoculant was applied at the rate of 50 mL/kg (fresh basis) of forage to achieve a final application rate of 1 × 10⁶ cfu/g of fresh matter (FM). Duplicate silos for each treatment were opened after 0, 3, 7, 10, 20, 30, 45 and 60 d for microbiological and chemical analysis. The results showed that the addition of CSL significantly increased crude protein (CP) contents, and decreased neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents of treatments after 60 d of ensiling (P < 0.05). The lactic acid contents in C4 and C3 were significantly higher than that in C1 (P < 0.05). In summary, mixing fresh rice straw with CSL at addition levels of 4:1 (C4) and 3:1 (C3) can improve the fermentation quality and nutrient composition of fresh rice straw silage. However, a large proportion of CSL (C3) had a negative impact on the aerobic stability of fresh rice straw.

Biogas production and microbial community shift through neutral pH control during the anaerobic digestion of pig manure

Laboratory-scale reactors, in which the pH could be auto-adjusted, were employed to investigate the mesophilic methane fermentation with pig manure (7.8% total solids) at pH 6.0, 7.0, and 8.0. Results showed that the performance of anaerobic digestion was strongly dependent on pH value. Biogas production and methane content at neutral pH 7.0 were significantly higher (16,607mL, 51.81%) than those at pH 6.0 (6916mL, 42.9%) and 8.0 (9739mL, 35.6%). Denaturing gradient gel electrophoresis fingerprinting and Shannon's index indicated that the samples contained highly diverse microbial communities. The major genus at pH 7.0 was Methanocorpusculum, compared with that was Methanosarcina at both pH 6.0 and 8.0. Our research revealed that cultures maintained at pH 7.0 could support increased biogas production, which has significant implications for the scale-up biogas engineering.

Fermentation characteristics and lactic Acid bacteria succession of total mixed ration silages formulated with peach pomace

The objective of this study was to assess the use of peach pomace in total mixed ration (TMR) silages and clarify the differences in aerobic stability between TMR and TMR silages caused by lactic acid bacteria (LAB). The TMR were prepared using peach pomace, alfalfa hay or Leymus chinensis hay, maize meal, soybean meal, cotton meal, limestone, a vitamin-mineral supplement, and salt in a ratio of 6.0:34.0:44.4:7.0:5.0:2.5:1.0:0.1 on a dry matter (DM) basis. Fermentation quality, microbial composition, and the predominant LAB were examined during ensiling and aerobic deterioration. The results indicated that the TMR silages with peach pomace were well fermented, with low pH and high lactic acid concentrations. The aerobic stability of TMR silages were significantly higher than that of TMR. Compared with TMR silages with alfalfa hay, TMR silage with Leymus chinensis hay was much more prone to deterioration. Although the dominant LAB were not identical in TMR, the same dominant species, Lactobacillus buchneri and Pediococcus acidilactici, were found in both types of TMR silages after 56 d of ensiling, and they may play an important role in the aerobic stability of TMR silages.

Ensiling Characteristics and the In situ Nutrient Degradability of a By-product Feed-based Silage

This study was conducted to evaluate the ensiling characteristics and the in situ degradability of a by-product feed (BF)-based silage. Before ensilation, the BF-based mixture was composed of 50% spent mushroom substrate, 21% recycled poultry bedding, 15% ryegrass straw, 10.8% rice bran, 2% molasses, 0.6% bentonite, and 0.6% microbial inoculant on a wet basis and ensiled for up to 4 weeks. The BF-based silage contained on average 39.3% moisture, 13.4% crude protein (CP), and 52.2% neutral detergent fiber (NDF), 49% total digestible nutrient, and 37.8% physically effective NDF1.18 on a dry matter (DM) basis. Ensiling the BF-based silage for up to 4 weeks affected (p<0.01) the chemical composition to a small extent, increased (p<0.05) the lactic acid and NH3-N content, and decreased (p<0.05) both the total bacterial and lactic acid bacterial counts from 10(9) to 10(8) cfu/g when compared to that before ensiling. These parameters indicated that the silage was fermented and stored well during the 4-week ensiling period. Compared with rice or ryegrass straws, the BF-based silage had a higher (p<0.05) water-soluble and filterable fraction, a lower insoluble degradable DM and CP fraction (p<0.05), a lower digestible NDF (p<0.05) fraction, a higher (p<0.05) DM and CP disappearance and degradability rate, and a lower (p<0.05) NDF disappearance and degradability rate. These results indicated that cheap, good-quality BF-based roughage could be produced by ensiling SMS, RPB, rice bran, and a minimal amount of straw.

Anaerobic digestion of municipal solid waste composed of food waste, wastepaper, and plastic in a single-stage system: performance and microbial community structure characterization

The performance of municipal organic solid waste anaerobic digestion was investigated using a single-stage bioreactor, and the microbial community structures were characterized during the digestion. The results showed that the biogas and methane production rates were 592.4 and 370.1L/kg with volatile solid added at the ratio of 2:1:1 for food waste, wastepaper, and plastic based on dry weight. The methane volume concentration fluctuated between 44.3% and 75.4% at steady stage. Acetic acid, propionic acid, and butyric acid were the major volatile fatty acids produced during the digestion process. The anaerobic process was not inhibited by the accumulation of ammonia and free ammonia. The bacterial community was found to consist of at least 21 bands of bacteria and 12 bands of archaea at the steady state. All of the results indicated that the mixture of food waste, wastepaper, and plastic could be efficiently co-digested using the anaerobic digestion system.

Organic loading rate shock impact on operation and microbial communities in different anaerobic fixed-bed reactors

For the fixed-bed reactors in this experiment, during 40 days of stable operation and under different organic loading shocks, biogas production remained stable at 21 L, effluent pH remained between 6.8 and 7.5, and chemical oxygen demand (COD) removal efficiency and the biogas methane content were greater than 80% and 75%, respectively. The community was analyzed using denaturing gradient gel electrophoresis (DGGE), 16S rRNA gene clone library screening, and quantitative PCR. Findings revealed that bacteria and methanogenic archaea were typically dominant in the adhering sludge. Methanomicrobiales was identified in carbon fiber carriers, they were breeding slowly, and attached easily. The 16S rRNA gene concentration of methanogenic archaea was higher in the adhering sludge than in the deposited sludge. Our results indicated that the colonization of the microorganism played a very important role in the carbon fiber carriers, as well as in the improvement of sludge activity and the shock resistance of the reactor.

Bioreactor performance and methanogenic population dynamics in a low-temperature (5-18 °C) anaerobic fixed-bed reactor

The effect of temperature on the functionality of microbial community structure in a low temperature, anaerobic fixed-bed reactor was studied by decreasing the operating temperature from 18 °C to 5 °C. The reactor was productive within 20 days and produced stable methane content in biogas (above 77%) throughout the trial period. At 17 °C and 15 °C, chemical oxygen demand (COD) removal efficiency and biogas production of reactor were significantly reduced. These might be temperature thresholds when fixed-bed reactors are operated under low temperatures. The methanogen community composition was analyzed using 16S rRNA gene clone library screening and quantitative PCR. At low ambient temperatures, Methanomicrobiales were dominant methanogens, and they preferentially adhered to the carbon fiber carrier. The results indicated that 16S rRNA levels of Methanomicrobiales and Methanosaetaceae in adhering sludge were higher than in deposited sludge, and they all contributed to the efficient performance of the fixed-bed reactor at low operating temperatures.

Effects of fermented mushroom (Flammulina velutipes) by-product diets on growth performance and carcass traits in growing-fattening Berkshire pigs

This study was conducted to investigate effects of fermented mushroom (Flammulina velutipes) by-product diets on the growth performance and carcass traits in growing-fattening Berkshire pigs. The fermented diets mainly contained 40.0% mushroom by-product, 20.0% formula feed, 26.0% rice bran and supplemental 0.1% probiotics. The mixed ingredients were fermented for 5days at room temperature. Berkshire pigs (n=225) were divided into five groups and three replications. The basal diets (C) were substituted by 10% (T1), 30% (T2), 50% (T3) and 70% (T4) fermented mushroom by-product diets. Crude protein concentration and total calorie in fermented diets were significantly increased (P<0.05) at the end of fermentation days compared with initial fermentation day. Body weight gain, feed efficiency and carcass weight were significantly lower (P<0.05) in the T2, T3 and T4 groups than in the control group. Carcass grade was significantly better (P<0.05) in the pigs fed fermented diets than in the pigs fed control diet and the ratio of high grade (1 plus 2 grades) was higher in the fermented diet groups compared with the control group. Therefore, although a diet of fermented mushroom by-product decreased growth performance and feed efficiency, it improved the carcass grade in Berkshire pigs.

Selection and characteristics of a switchgrass-colonizing microbial community to produce extracellular cellulases and xylanases

A microbial community was selected for growth on dried and NaOH-treated switchgrass. During a 14-day liquid cultivation, a 70% loss in dry weight was observed during the first 4 days and after 14 days, the hemicellulose and cellulose in the system were degraded by 73.5% and 67.3%, respectively. The carboxymethyl cellulase (CMCase) and xylanase levels reached 0.21 and 3.75 IU, respectively. The optimal pH for CMCase and xylanase activities was 5 and 6, respectively. The optimal reaction temperature of CMCase and xylanase was 60°C. A library of bacterial and fungal ribosomal gene sequences obtained from the community showed the presence of Achromobacter xylosoxidans and Alcaligenes faecalis and of Fusarium sporotrichioides. To our knowledge, this was the first report on a microbial community selected in the presence of switchgrass to produce extracellular cellulases and xylanases.

Improvement of L-lactic acid production from Jerusalem artichoke tubers by mixed culture of Aspergillus niger and Lactobacillus sp

Aspergillus niger SL-09 and Lactobacillus sp. G-02 were used as a mixed culture in a 7-l fermentor to directly form L-lactic acid from Jerusalem artichoke tubers. The synthesis of inulinase and invertase from A. niger SL-09 was enhanced significantly by the inoculation of Lactobacillus sp. G-02 at 12h of culture, which reached 275.6 and 571.8 U/ml in 60 h, over 5-folds higher than that of the culture using single strain. In the following simultaneous saccharification and fermentation procedure, the highest L-lactic acid concentration of 120.5 g/l was obtained in 36 h of the fed-batch fermentation with high conversion efficiency of 94.5%.

Molasses and microbial inoculants improve fermentability and silage quality of cotton waste-based spent mushroom substrate

A small-silo study was conducted to develop an effective ensiling storage method for the use of cotton waste-based spent mushroom substrate (SMS) as an animal feed. The SMS was ensiled with 5% molasses (DM basis), 0.5% (v/w) lactic acid bacteria (LAB, Lactobacillus plantarum) inoculant or 0.5% (v/w) yeast (Saccharomyces cerevisiae) inoculant. The treatments included 100% SMS (control), 95% SMS+5% molasses (T1), 95% SMS+5% molasses+0.5% LAB (T2) and 95% SMS+5% molasses+5% LAB+0.5% yeast (T3). The treatments were ensiled for 10. Change in chemical compositions was little (P>0.05) according to the ensiling process and treatments. Compared with those before ensiling, 100% SMS (control) after ensiling showed unstable fermentative properties with high pH (5.2) and little lactic acid production. Compared with the ensiled control, treatments (T1, T2 and T3) resulted in decreased pH, 18-20 times higher concentrations of lactic acid, and greater populations of total bacteria (P<0.07), LAB and yeast (P<0.07). The addition of 5% molasses, 0.5% LAB and 0.5% yeast (T3) to the SMS resulted in the lowest pH (4.25) and the greatest microbial populations. Treatment T3 was selected for a large scale silo study which was ensiled for 10, 20 and 30 d. As in the small-silo study, the T3 treatment showed favorable fermentative and microbial parameters, compared with the control, by decreasing pH and increasing lactic acid concentrations, LAB and yeast populations. The minimum ensiling period was 20 d, when pH was reasonably low and LAB and yeast populations were greatest. In conclusion, molasses and microbial inoculation improved silage quality of SMS.