https://www.sbmicrobiologia.org.br/PDF/4.pdf

Bio-hydrogen production from waste materials

Factors influencing fermentative hydrogen production: a review

Over 160 publications related to fermentative hydrogen production from wastewater and solid wastes by mixed cultures are compiled and analyzed. Of the 98 reported cases, 57 used single substrates (mainly carbohydrates), 8 used actual wastewater, and 33 used solid wastes for hydrogen conversion. The key information is compiled in four tables: (1) pretreatment conditions for screening hydrogen-producing bacteria from anaerobic sludge or soil, and the process and performance parameters for (2) single substrates in synthetic wastewaters, (3) actual wastewaters, and (4) solid wastes. Process parameters discussed include pH, temperature, hydraulic retention time, seed sludge, nutrients, inhibitors, reactor design, and the means used for lowering hydrogen partial pressure. Performance parameters discussed include hydrogen yield, maximum volumetric production rate, maximum specific production rate, and conversion efficiency. The outlook for this new technology is discussed at the end.

Fermentative Hydrogen Production From Wastewater and Solid Wastes by Mixed Cultures

Biohydrogen production from biomass and industrial wastes by dark fermentation

Two centuries after the discovery of chitin, it is widely accepted that this biopolymer is an important biomaterial in many aspects. Numerous studies on chitin have focused on its biomedical applications. In this review, various aspects of chitin research including sources, structure, biosynthesis, chitinolytic enzyme, chitin binding protein, genetic engineering approach to produce chitin, chitin and evolution, and a wide range of applications in bio- and nanotechnology will be dealt with.

Chitin Research Revisited

Conversion of chitinous wastes to hydrogen gas by clostridium paraputrificum M-21

Identification and characterization of Clostridium paraputrificum M-21, a chitinolytic, mesophilic and hydrogen-producing bacterium.

In vitro digestibility methods have been developed to overcome problems in the in vivo digestibility measurement, but its accuracy should be tested in a local setting. In vitro methods developed by Tilley and Terry (T2), Theodorou (T3) and Sutardi (T4) have been compared to in vivo method (T1) in a block randomized design study. Four heifers FH (337.50 ± 45.87 kg BW) were used in T1, and two fistulated FH bulls (510 ± 20 kg BW) were used as inoculant sources in the in vitro methods. Dairy cattle ration consisted of 54.0% Napier grass and 46.0% concentrate with 58.8% DM, 12.1% ash, 10.0% CP, 3.3% EE, 26.5% CF, and 61.1% TDN. The observed parameters were ration fermentability (pH, NH3, and VFA concentration) and digestibility (DMD and OMD). The data were analyzed using analysis of variance (ANOVA) followed by the Tukey test. The correlation was made before regression analysis to estimate the in vivo parameters from the in vitro. The results showed that pH values are in the normal range (6.7 – 6.8), and insignificantly different between treatments (P>0.05). The concentration of NH3 and VFA were significantly different between the treatments (P<0.05), but T2 produced similar NH3 and VFA concentrations to T1. Similar results were also found in the DMD and OMD. Correlation analysis showed that pH value of T3 correlated significantly with T1, while DMD value of T4 correlated to T1. The T1 DMD (Y) could be estimated from T4 DMD (X) using formula Y (%) = y = -0.091x2 + 9.1632x - 168.4. It is concluded that tropical dairy feedstuffs in vitro digestibility using Tilley and Terry’s method produced similar result to in vivo digestibility method, but in vivo dry matter digestibility can be estimated accurately by in vitro dry matter digestibility using Sutardi method.

https://doi.org/10.1088/1755-1315/951/1/012012

The accuracy of several in vitro methods in estimating in vivo digestibility of the tropical dairy ration

Palm oil is an abundant source of oil in Indonesia and some other tropical countries. This research aimed to investigate the effect of palm oil supplementation levels on in vitro rumen fermentability by integrating data from various related studies. The data used were 40 data points from 13 studies which reported different levels of palm oil supplementation on in vitro rumen fermentability and nutrient digestibility. Data were tabulated, uniformed for the unit in each parameter, then analyzed using a linear regression method by employing SPSS software version 20. The results showed that palm oil supplementation significantly (P<0.05) increased bacterial population and isobutyrate proportion, while reduced protozoa population, and tended to reduce total volatile fatty acids (P<0.1). Supplementation of palm oil did not affect dry mater digestibility, organic matter digestibility, methane emission, pH, total gas, ammonia, acetate proportion, propionate, butyrate, valerate and isovalerate. It can be concluded that palm oil supplementation modifies some parameters of in vitro rumen fermentation.

Effect of palm oil supplementation level on in vitro ruminal fermentability

Background and Aim: Disposable imported nylon bags used in an in situ digestibility measurement restrict the effort of scientists to obtain more accurate information about ruminant feed quality due to their low affordability and environmentally unfriendly characteristics. This study aimed to find reusable local nylon fabrics to substitute imports. Materials and Methods: Five local fabrics (B1 = Abutai, B2 = Taffeta, B3 = Organza, B4 = N57, and B5 = M100) were used to make nylon bags and compared with the imported bag (B6 = Ankom technology). The research consisted of three steps: (1) Observing the similarity of the local nylon bag’s hole number to the imported bag. (2) Testing feed in situ degradation (F1 = Napier grass, F2 = Cornmeal, and F3 = Dairy cattle total mixed ration) using bags B1–B6. (3) The reusability of the bag was tested using different washing methods (under running water [R1], rinse [R2], and ultrasonic water bath [R3]). Results: It was shown that the hole numbers of B1 (1223 hole numbers) and B2 (1245 hole numbers) were not significantly different from B6 (1248 hole numbers). It was shown with dry matter degradability measurement using the in situ method that there was no significant difference in feed solubility (a), potential degradability (b), and the effective degradation between local fabrics (B1–B5) and B6. According to the degradation rate (c), there were interactions between the feeds and fabrics. For F1, all local fabrics were similar to B6, while for F2, only B1 was different from B6. For F3, only B5 was different from B6. It was also shown by the organic matter degradability measurements that there was a similar trend. The exception was the solubility (a) component in F3, in which it was shown that B1 was also different from B6. It was shown in the reusable test that there was no difference in the weight of the bag before and after all washing methods. In contrast, the hole number increased due to the shrinking of the bag after drying in a 60°C oven. Conclusion: According to this in situ study, local nylon bag B2 can substitute imported bags. A lower drying temperature is suggested to prevent shrinking and make the bag reusable.

Dwierra Evvyernie

Papers

Conversion of chitinous wastes to hydrogen gas by clostridium paraputrificum M-21

Identification and characterization of Clostridium paraputrificum M-21, a chitinolytic, mesophilic and hydrogen-producing bacterium.

The accuracy of several in vitro methods in estimating in vivo digestibility of the tropical dairy ration

Effect of palm oil supplementation level on in vitro ruminal fermentability

In situ degradation of dairy cattle feedstuffs using reusable local nylon fabric bags